xref: /openbmc/qemu/hw/virtio/virtio.c (revision 3b43302c71854b263a4653b708699ce074082158)
1 /*
2  * Virtio Support
3  *
4  * Copyright IBM, Corp. 2007
5  *
6  * Authors:
7  *  Anthony Liguori   <aliguori@us.ibm.com>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2.  See
10  * the COPYING file in the top-level directory.
11  *
12  */
13 
14 #include "qemu/osdep.h"
15 #include "qapi/error.h"
16 #include "qapi/qmp/qdict.h"
17 #include "qapi/qapi-commands-virtio.h"
18 #include "qapi/qapi-commands-qom.h"
19 #include "qapi/qapi-visit-virtio.h"
20 #include "qapi/qmp/qjson.h"
21 #include "cpu.h"
22 #include "trace.h"
23 #include "qemu/error-report.h"
24 #include "qemu/log.h"
25 #include "qemu/main-loop.h"
26 #include "qemu/module.h"
27 #include "qom/object_interfaces.h"
28 #include "hw/virtio/virtio.h"
29 #include "migration/qemu-file-types.h"
30 #include "qemu/atomic.h"
31 #include "hw/virtio/virtio-bus.h"
32 #include "hw/qdev-properties.h"
33 #include "hw/virtio/virtio-access.h"
34 #include "sysemu/dma.h"
35 #include "sysemu/runstate.h"
36 #include "standard-headers/linux/virtio_ids.h"
37 #include "standard-headers/linux/vhost_types.h"
38 #include "standard-headers/linux/virtio_blk.h"
39 #include "standard-headers/linux/virtio_console.h"
40 #include "standard-headers/linux/virtio_gpu.h"
41 #include "standard-headers/linux/virtio_net.h"
42 #include "standard-headers/linux/virtio_scsi.h"
43 #include "standard-headers/linux/virtio_i2c.h"
44 #include "standard-headers/linux/virtio_balloon.h"
45 #include "standard-headers/linux/virtio_iommu.h"
46 #include "standard-headers/linux/virtio_mem.h"
47 #include "standard-headers/linux/virtio_vsock.h"
48 #include CONFIG_DEVICES
49 
50 /* QAPI list of realized VirtIODevices */
51 static QTAILQ_HEAD(, VirtIODevice) virtio_list;
52 
53 /*
54  * Maximum size of virtio device config space
55  */
56 #define VHOST_USER_MAX_CONFIG_SIZE 256
57 
58 #define FEATURE_ENTRY(name, desc) (qmp_virtio_feature_map_t) \
59     { .virtio_bit = name, .feature_desc = desc }
60 
61 enum VhostUserProtocolFeature {
62     VHOST_USER_PROTOCOL_F_MQ = 0,
63     VHOST_USER_PROTOCOL_F_LOG_SHMFD = 1,
64     VHOST_USER_PROTOCOL_F_RARP = 2,
65     VHOST_USER_PROTOCOL_F_REPLY_ACK = 3,
66     VHOST_USER_PROTOCOL_F_NET_MTU = 4,
67     VHOST_USER_PROTOCOL_F_SLAVE_REQ = 5,
68     VHOST_USER_PROTOCOL_F_CROSS_ENDIAN = 6,
69     VHOST_USER_PROTOCOL_F_CRYPTO_SESSION = 7,
70     VHOST_USER_PROTOCOL_F_PAGEFAULT = 8,
71     VHOST_USER_PROTOCOL_F_CONFIG = 9,
72     VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD = 10,
73     VHOST_USER_PROTOCOL_F_HOST_NOTIFIER = 11,
74     VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD = 12,
75     VHOST_USER_PROTOCOL_F_RESET_DEVICE = 13,
76     VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS = 14,
77     VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS = 15,
78     VHOST_USER_PROTOCOL_F_MAX
79 };
80 
81 /* Virtio transport features mapping */
82 static qmp_virtio_feature_map_t virtio_transport_map[] = {
83     /* Virtio device transport features */
84 #ifndef VIRTIO_CONFIG_NO_LEGACY
85     FEATURE_ENTRY(VIRTIO_F_NOTIFY_ON_EMPTY, \
86             "VIRTIO_F_NOTIFY_ON_EMPTY: Notify when device runs out of avail. "
87             "descs. on VQ"),
88     FEATURE_ENTRY(VIRTIO_F_ANY_LAYOUT, \
89             "VIRTIO_F_ANY_LAYOUT: Device accepts arbitrary desc. layouts"),
90 #endif /* !VIRTIO_CONFIG_NO_LEGACY */
91     FEATURE_ENTRY(VIRTIO_F_VERSION_1, \
92             "VIRTIO_F_VERSION_1: Device compliant for v1 spec (legacy)"),
93     FEATURE_ENTRY(VIRTIO_F_IOMMU_PLATFORM, \
94             "VIRTIO_F_IOMMU_PLATFORM: Device can be used on IOMMU platform"),
95     FEATURE_ENTRY(VIRTIO_F_RING_PACKED, \
96             "VIRTIO_F_RING_PACKED: Device supports packed VQ layout"),
97     FEATURE_ENTRY(VIRTIO_F_IN_ORDER, \
98             "VIRTIO_F_IN_ORDER: Device uses buffers in same order as made "
99             "available by driver"),
100     FEATURE_ENTRY(VIRTIO_F_ORDER_PLATFORM, \
101             "VIRTIO_F_ORDER_PLATFORM: Memory accesses ordered by platform"),
102     FEATURE_ENTRY(VIRTIO_F_SR_IOV, \
103             "VIRTIO_F_SR_IOV: Device supports single root I/O virtualization"),
104     /* Virtio ring transport features */
105     FEATURE_ENTRY(VIRTIO_RING_F_INDIRECT_DESC, \
106             "VIRTIO_RING_F_INDIRECT_DESC: Indirect descriptors supported"),
107     FEATURE_ENTRY(VIRTIO_RING_F_EVENT_IDX, \
108             "VIRTIO_RING_F_EVENT_IDX: Used & avail. event fields enabled"),
109     { -1, "" }
110 };
111 
112 /* Vhost-user protocol features mapping */
113 static qmp_virtio_feature_map_t vhost_user_protocol_map[] = {
114     FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_MQ, \
115             "VHOST_USER_PROTOCOL_F_MQ: Multiqueue protocol supported"),
116     FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_LOG_SHMFD, \
117             "VHOST_USER_PROTOCOL_F_LOG_SHMFD: Shared log memory fd supported"),
118     FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_RARP, \
119             "VHOST_USER_PROTOCOL_F_RARP: Vhost-user back-end RARP broadcasting "
120             "supported"),
121     FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_REPLY_ACK, \
122             "VHOST_USER_PROTOCOL_F_REPLY_ACK: Requested operation status ack. "
123             "supported"),
124     FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_NET_MTU, \
125             "VHOST_USER_PROTOCOL_F_NET_MTU: Expose host MTU to guest supported"),
126     FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_SLAVE_REQ, \
127             "VHOST_USER_PROTOCOL_F_SLAVE_REQ: Socket fd for back-end initiated "
128             "requests supported"),
129     FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_CROSS_ENDIAN, \
130             "VHOST_USER_PROTOCOL_F_CROSS_ENDIAN: Endianness of VQs for legacy "
131             "devices supported"),
132     FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_CRYPTO_SESSION, \
133             "VHOST_USER_PROTOCOL_F_CRYPTO_SESSION: Session creation for crypto "
134             "operations supported"),
135     FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_PAGEFAULT, \
136             "VHOST_USER_PROTOCOL_F_PAGEFAULT: Request servicing on userfaultfd "
137             "for accessed pages supported"),
138     FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_CONFIG, \
139             "VHOST_USER_PROTOCOL_F_CONFIG: Vhost-user messaging for virtio "
140             "device configuration space supported"),
141     FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD, \
142             "VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD: Slave fd communication "
143             "channel supported"),
144     FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_HOST_NOTIFIER, \
145             "VHOST_USER_PROTOCOL_F_HOST_NOTIFIER: Host notifiers for specified "
146             "VQs supported"),
147     FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD, \
148             "VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD: Shared inflight I/O buffers "
149             "supported"),
150     FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_RESET_DEVICE, \
151             "VHOST_USER_PROTOCOL_F_RESET_DEVICE: Disabling all rings and "
152             "resetting internal device state supported"),
153     FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS, \
154             "VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS: In-band messaging "
155             "supported"),
156     FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS, \
157             "VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS: Configuration for "
158             "memory slots supported"),
159     { -1, "" }
160 };
161 
162 /* virtio device configuration statuses */
163 static qmp_virtio_feature_map_t virtio_config_status_map[] = {
164     FEATURE_ENTRY(VIRTIO_CONFIG_S_DRIVER_OK, \
165             "VIRTIO_CONFIG_S_DRIVER_OK: Driver setup and ready"),
166     FEATURE_ENTRY(VIRTIO_CONFIG_S_FEATURES_OK, \
167             "VIRTIO_CONFIG_S_FEATURES_OK: Feature negotiation complete"),
168     FEATURE_ENTRY(VIRTIO_CONFIG_S_DRIVER, \
169             "VIRTIO_CONFIG_S_DRIVER: Guest OS compatible with device"),
170     FEATURE_ENTRY(VIRTIO_CONFIG_S_NEEDS_RESET, \
171             "VIRTIO_CONFIG_S_NEEDS_RESET: Irrecoverable error, device needs "
172             "reset"),
173     FEATURE_ENTRY(VIRTIO_CONFIG_S_FAILED, \
174             "VIRTIO_CONFIG_S_FAILED: Error in guest, device failed"),
175     FEATURE_ENTRY(VIRTIO_CONFIG_S_ACKNOWLEDGE, \
176             "VIRTIO_CONFIG_S_ACKNOWLEDGE: Valid virtio device found"),
177     { -1, "" }
178 };
179 
180 /* virtio-blk features mapping */
181 qmp_virtio_feature_map_t virtio_blk_feature_map[] = {
182     FEATURE_ENTRY(VIRTIO_BLK_F_SIZE_MAX, \
183             "VIRTIO_BLK_F_SIZE_MAX: Max segment size is size_max"),
184     FEATURE_ENTRY(VIRTIO_BLK_F_SEG_MAX, \
185             "VIRTIO_BLK_F_SEG_MAX: Max segments in a request is seg_max"),
186     FEATURE_ENTRY(VIRTIO_BLK_F_GEOMETRY, \
187             "VIRTIO_BLK_F_GEOMETRY: Legacy geometry available"),
188     FEATURE_ENTRY(VIRTIO_BLK_F_RO, \
189             "VIRTIO_BLK_F_RO: Device is read-only"),
190     FEATURE_ENTRY(VIRTIO_BLK_F_BLK_SIZE, \
191             "VIRTIO_BLK_F_BLK_SIZE: Block size of disk available"),
192     FEATURE_ENTRY(VIRTIO_BLK_F_TOPOLOGY, \
193             "VIRTIO_BLK_F_TOPOLOGY: Topology information available"),
194     FEATURE_ENTRY(VIRTIO_BLK_F_MQ, \
195             "VIRTIO_BLK_F_MQ: Multiqueue supported"),
196     FEATURE_ENTRY(VIRTIO_BLK_F_DISCARD, \
197             "VIRTIO_BLK_F_DISCARD: Discard command supported"),
198     FEATURE_ENTRY(VIRTIO_BLK_F_WRITE_ZEROES, \
199             "VIRTIO_BLK_F_WRITE_ZEROES: Write zeroes command supported"),
200 #ifndef VIRTIO_BLK_NO_LEGACY
201     FEATURE_ENTRY(VIRTIO_BLK_F_BARRIER, \
202             "VIRTIO_BLK_F_BARRIER: Request barriers supported"),
203     FEATURE_ENTRY(VIRTIO_BLK_F_SCSI, \
204             "VIRTIO_BLK_F_SCSI: SCSI packet commands supported"),
205     FEATURE_ENTRY(VIRTIO_BLK_F_FLUSH, \
206             "VIRTIO_BLK_F_FLUSH: Flush command supported"),
207     FEATURE_ENTRY(VIRTIO_BLK_F_CONFIG_WCE, \
208             "VIRTIO_BLK_F_CONFIG_WCE: Cache writeback and writethrough modes "
209             "supported"),
210 #endif /* !VIRTIO_BLK_NO_LEGACY */
211     FEATURE_ENTRY(VHOST_F_LOG_ALL, \
212             "VHOST_F_LOG_ALL: Logging write descriptors supported"),
213     FEATURE_ENTRY(VHOST_USER_F_PROTOCOL_FEATURES, \
214             "VHOST_USER_F_PROTOCOL_FEATURES: Vhost-user protocol features "
215             "negotiation supported"),
216     { -1, "" }
217 };
218 
219 /* virtio-serial features mapping */
220 qmp_virtio_feature_map_t virtio_serial_feature_map[] = {
221     FEATURE_ENTRY(VIRTIO_CONSOLE_F_SIZE, \
222             "VIRTIO_CONSOLE_F_SIZE: Host providing console size"),
223     FEATURE_ENTRY(VIRTIO_CONSOLE_F_MULTIPORT, \
224             "VIRTIO_CONSOLE_F_MULTIPORT: Multiple ports for device supported"),
225     FEATURE_ENTRY(VIRTIO_CONSOLE_F_EMERG_WRITE, \
226             "VIRTIO_CONSOLE_F_EMERG_WRITE: Emergency write supported"),
227     { -1, "" }
228 };
229 
230 /* virtio-gpu features mapping */
231 qmp_virtio_feature_map_t virtio_gpu_feature_map[] = {
232     FEATURE_ENTRY(VIRTIO_GPU_F_VIRGL, \
233             "VIRTIO_GPU_F_VIRGL: Virgl 3D mode supported"),
234     FEATURE_ENTRY(VIRTIO_GPU_F_EDID, \
235             "VIRTIO_GPU_F_EDID: EDID metadata supported"),
236     FEATURE_ENTRY(VIRTIO_GPU_F_RESOURCE_UUID, \
237             "VIRTIO_GPU_F_RESOURCE_UUID: Resource UUID assigning supported"),
238     FEATURE_ENTRY(VIRTIO_GPU_F_RESOURCE_BLOB, \
239             "VIRTIO_GPU_F_RESOURCE_BLOB: Size-based blob resources supported"),
240     FEATURE_ENTRY(VIRTIO_GPU_F_CONTEXT_INIT, \
241             "VIRTIO_GPU_F_CONTEXT_INIT: Context types and synchronization "
242             "timelines supported"),
243     FEATURE_ENTRY(VHOST_F_LOG_ALL, \
244             "VHOST_F_LOG_ALL: Logging write descriptors supported"),
245     FEATURE_ENTRY(VHOST_USER_F_PROTOCOL_FEATURES, \
246             "VHOST_USER_F_PROTOCOL_FEATURES: Vhost-user protocol features "
247             "negotiation supported"),
248     { -1, "" }
249 };
250 
251 /* virtio-input features mapping */
252 qmp_virtio_feature_map_t virtio_input_feature_map[] = {
253     FEATURE_ENTRY(VHOST_F_LOG_ALL, \
254             "VHOST_F_LOG_ALL: Logging write descriptors supported"),
255     FEATURE_ENTRY(VHOST_USER_F_PROTOCOL_FEATURES, \
256             "VHOST_USER_F_PROTOCOL_FEATURES: Vhost-user protocol features "
257             "negotiation supported"),
258     { -1, "" }
259 };
260 
261 /* virtio-net features mapping */
262 qmp_virtio_feature_map_t virtio_net_feature_map[] = {
263     FEATURE_ENTRY(VIRTIO_NET_F_CSUM, \
264             "VIRTIO_NET_F_CSUM: Device handling packets with partial checksum "
265             "supported"),
266     FEATURE_ENTRY(VIRTIO_NET_F_GUEST_CSUM, \
267             "VIRTIO_NET_F_GUEST_CSUM: Driver handling packets with partial "
268             "checksum supported"),
269     FEATURE_ENTRY(VIRTIO_NET_F_CTRL_GUEST_OFFLOADS, \
270             "VIRTIO_NET_F_CTRL_GUEST_OFFLOADS: Control channel offloading "
271             "reconfig. supported"),
272     FEATURE_ENTRY(VIRTIO_NET_F_MTU, \
273             "VIRTIO_NET_F_MTU: Device max MTU reporting supported"),
274     FEATURE_ENTRY(VIRTIO_NET_F_MAC, \
275             "VIRTIO_NET_F_MAC: Device has given MAC address"),
276     FEATURE_ENTRY(VIRTIO_NET_F_GUEST_TSO4, \
277             "VIRTIO_NET_F_GUEST_TSO4: Driver can receive TSOv4"),
278     FEATURE_ENTRY(VIRTIO_NET_F_GUEST_TSO6, \
279             "VIRTIO_NET_F_GUEST_TSO6: Driver can receive TSOv6"),
280     FEATURE_ENTRY(VIRTIO_NET_F_GUEST_ECN, \
281             "VIRTIO_NET_F_GUEST_ECN: Driver can receive TSO with ECN"),
282     FEATURE_ENTRY(VIRTIO_NET_F_GUEST_UFO, \
283             "VIRTIO_NET_F_GUEST_UFO: Driver can receive UFO"),
284     FEATURE_ENTRY(VIRTIO_NET_F_HOST_TSO4, \
285             "VIRTIO_NET_F_HOST_TSO4: Device can receive TSOv4"),
286     FEATURE_ENTRY(VIRTIO_NET_F_HOST_TSO6, \
287             "VIRTIO_NET_F_HOST_TSO6: Device can receive TSOv6"),
288     FEATURE_ENTRY(VIRTIO_NET_F_HOST_ECN, \
289             "VIRTIO_NET_F_HOST_ECN: Device can receive TSO with ECN"),
290     FEATURE_ENTRY(VIRTIO_NET_F_HOST_UFO, \
291             "VIRTIO_NET_F_HOST_UFO: Device can receive UFO"),
292     FEATURE_ENTRY(VIRTIO_NET_F_MRG_RXBUF, \
293             "VIRTIO_NET_F_MRG_RXBUF: Driver can merge receive buffers"),
294     FEATURE_ENTRY(VIRTIO_NET_F_STATUS, \
295             "VIRTIO_NET_F_STATUS: Configuration status field available"),
296     FEATURE_ENTRY(VIRTIO_NET_F_CTRL_VQ, \
297             "VIRTIO_NET_F_CTRL_VQ: Control channel available"),
298     FEATURE_ENTRY(VIRTIO_NET_F_CTRL_RX, \
299             "VIRTIO_NET_F_CTRL_RX: Control channel RX mode supported"),
300     FEATURE_ENTRY(VIRTIO_NET_F_CTRL_VLAN, \
301             "VIRTIO_NET_F_CTRL_VLAN: Control channel VLAN filtering supported"),
302     FEATURE_ENTRY(VIRTIO_NET_F_CTRL_RX_EXTRA, \
303             "VIRTIO_NET_F_CTRL_RX_EXTRA: Extra RX mode control supported"),
304     FEATURE_ENTRY(VIRTIO_NET_F_GUEST_ANNOUNCE, \
305             "VIRTIO_NET_F_GUEST_ANNOUNCE: Driver sending gratuitous packets "
306             "supported"),
307     FEATURE_ENTRY(VIRTIO_NET_F_MQ, \
308             "VIRTIO_NET_F_MQ: Multiqueue with automatic receive steering "
309             "supported"),
310     FEATURE_ENTRY(VIRTIO_NET_F_CTRL_MAC_ADDR, \
311             "VIRTIO_NET_F_CTRL_MAC_ADDR: MAC address set through control "
312             "channel"),
313     FEATURE_ENTRY(VIRTIO_NET_F_HASH_REPORT, \
314             "VIRTIO_NET_F_HASH_REPORT: Hash reporting supported"),
315     FEATURE_ENTRY(VIRTIO_NET_F_RSS, \
316             "VIRTIO_NET_F_RSS: RSS RX steering supported"),
317     FEATURE_ENTRY(VIRTIO_NET_F_RSC_EXT, \
318             "VIRTIO_NET_F_RSC_EXT: Extended coalescing info supported"),
319     FEATURE_ENTRY(VIRTIO_NET_F_STANDBY, \
320             "VIRTIO_NET_F_STANDBY: Device acting as standby for primary "
321             "device with same MAC addr. supported"),
322     FEATURE_ENTRY(VIRTIO_NET_F_SPEED_DUPLEX, \
323             "VIRTIO_NET_F_SPEED_DUPLEX: Device set linkspeed and duplex"),
324 #ifndef VIRTIO_NET_NO_LEGACY
325     FEATURE_ENTRY(VIRTIO_NET_F_GSO, \
326             "VIRTIO_NET_F_GSO: Handling GSO-type packets supported"),
327 #endif /* !VIRTIO_NET_NO_LEGACY */
328     FEATURE_ENTRY(VHOST_NET_F_VIRTIO_NET_HDR, \
329             "VHOST_NET_F_VIRTIO_NET_HDR: Virtio-net headers for RX and TX "
330             "packets supported"),
331     FEATURE_ENTRY(VHOST_F_LOG_ALL, \
332             "VHOST_F_LOG_ALL: Logging write descriptors supported"),
333     FEATURE_ENTRY(VHOST_USER_F_PROTOCOL_FEATURES, \
334             "VHOST_USER_F_PROTOCOL_FEATURES: Vhost-user protocol features "
335             "negotiation supported"),
336     { -1, "" }
337 };
338 
339 /* virtio-scsi features mapping */
340 qmp_virtio_feature_map_t virtio_scsi_feature_map[] = {
341     FEATURE_ENTRY(VIRTIO_SCSI_F_INOUT, \
342             "VIRTIO_SCSI_F_INOUT: Requests including read and writable data "
343             "buffers suppoted"),
344     FEATURE_ENTRY(VIRTIO_SCSI_F_HOTPLUG, \
345             "VIRTIO_SCSI_F_HOTPLUG: Reporting and handling hot-plug events "
346             "supported"),
347     FEATURE_ENTRY(VIRTIO_SCSI_F_CHANGE, \
348             "VIRTIO_SCSI_F_CHANGE: Reporting and handling LUN changes "
349             "supported"),
350     FEATURE_ENTRY(VIRTIO_SCSI_F_T10_PI, \
351             "VIRTIO_SCSI_F_T10_PI: T10 info included in request header"),
352     FEATURE_ENTRY(VHOST_F_LOG_ALL, \
353             "VHOST_F_LOG_ALL: Logging write descriptors supported"),
354     FEATURE_ENTRY(VHOST_USER_F_PROTOCOL_FEATURES, \
355             "VHOST_USER_F_PROTOCOL_FEATURES: Vhost-user protocol features "
356             "negotiation supported"),
357     { -1, "" }
358 };
359 
360 /* virtio/vhost-user-fs features mapping */
361 qmp_virtio_feature_map_t virtio_fs_feature_map[] = {
362     FEATURE_ENTRY(VHOST_F_LOG_ALL, \
363             "VHOST_F_LOG_ALL: Logging write descriptors supported"),
364     FEATURE_ENTRY(VHOST_USER_F_PROTOCOL_FEATURES, \
365             "VHOST_USER_F_PROTOCOL_FEATURES: Vhost-user protocol features "
366             "negotiation supported"),
367     { -1, "" }
368 };
369 
370 /* virtio/vhost-user-i2c features mapping */
371 qmp_virtio_feature_map_t virtio_i2c_feature_map[] = {
372     FEATURE_ENTRY(VIRTIO_I2C_F_ZERO_LENGTH_REQUEST, \
373             "VIRTIO_I2C_F_ZERO_LEGNTH_REQUEST: Zero length requests supported"),
374     FEATURE_ENTRY(VHOST_F_LOG_ALL, \
375             "VHOST_F_LOG_ALL: Logging write descriptors supported"),
376     FEATURE_ENTRY(VHOST_USER_F_PROTOCOL_FEATURES, \
377             "VHOST_USER_F_PROTOCOL_FEATURES: Vhost-user protocol features "
378             "negotiation supported"),
379     { -1, "" }
380 };
381 
382 /* virtio/vhost-vsock features mapping */
383 qmp_virtio_feature_map_t virtio_vsock_feature_map[] = {
384     FEATURE_ENTRY(VIRTIO_VSOCK_F_SEQPACKET, \
385             "VIRTIO_VSOCK_F_SEQPACKET: SOCK_SEQPACKET supported"),
386     FEATURE_ENTRY(VHOST_F_LOG_ALL, \
387             "VHOST_F_LOG_ALL: Logging write descriptors supported"),
388     FEATURE_ENTRY(VHOST_USER_F_PROTOCOL_FEATURES, \
389             "VHOST_USER_F_PROTOCOL_FEATURES: Vhost-user protocol features "
390             "negotiation supported"),
391     { -1, "" }
392 };
393 
394 /* virtio-balloon features mapping */
395 qmp_virtio_feature_map_t virtio_balloon_feature_map[] = {
396     FEATURE_ENTRY(VIRTIO_BALLOON_F_MUST_TELL_HOST, \
397             "VIRTIO_BALLOON_F_MUST_TELL_HOST: Tell host before reclaiming "
398             "pages"),
399     FEATURE_ENTRY(VIRTIO_BALLOON_F_STATS_VQ, \
400             "VIRTIO_BALLOON_F_STATS_VQ: Guest memory stats VQ available"),
401     FEATURE_ENTRY(VIRTIO_BALLOON_F_DEFLATE_ON_OOM, \
402             "VIRTIO_BALLOON_F_DEFLATE_ON_OOM: Deflate balloon when guest OOM"),
403     FEATURE_ENTRY(VIRTIO_BALLOON_F_FREE_PAGE_HINT, \
404             "VIRTIO_BALLOON_F_FREE_PAGE_HINT: VQ reporting free pages enabled"),
405     FEATURE_ENTRY(VIRTIO_BALLOON_F_PAGE_POISON, \
406             "VIRTIO_BALLOON_F_PAGE_POISON: Guest page poisoning enabled"),
407     FEATURE_ENTRY(VIRTIO_BALLOON_F_REPORTING, \
408             "VIRTIO_BALLOON_F_REPORTING: Page reporting VQ enabled"),
409     { -1, "" }
410 };
411 
412 /* virtio-crypto features mapping */
413 qmp_virtio_feature_map_t virtio_crypto_feature_map[] = {
414     FEATURE_ENTRY(VHOST_F_LOG_ALL, \
415             "VHOST_F_LOG_ALL: Logging write descriptors supported"),
416     { -1, "" }
417 };
418 
419 /* virtio-iommu features mapping */
420 qmp_virtio_feature_map_t virtio_iommu_feature_map[] = {
421     FEATURE_ENTRY(VIRTIO_IOMMU_F_INPUT_RANGE, \
422             "VIRTIO_IOMMU_F_INPUT_RANGE: Range of available virtual addrs. "
423             "available"),
424     FEATURE_ENTRY(VIRTIO_IOMMU_F_DOMAIN_RANGE, \
425             "VIRTIO_IOMMU_F_DOMAIN_RANGE: Number of supported domains "
426             "available"),
427     FEATURE_ENTRY(VIRTIO_IOMMU_F_MAP_UNMAP, \
428             "VIRTIO_IOMMU_F_MAP_UNMAP: Map and unmap requests available"),
429     FEATURE_ENTRY(VIRTIO_IOMMU_F_BYPASS, \
430             "VIRTIO_IOMMU_F_BYPASS: Endpoints not attached to domains are in "
431             "bypass mode"),
432     FEATURE_ENTRY(VIRTIO_IOMMU_F_PROBE, \
433             "VIRTIO_IOMMU_F_PROBE: Probe requests available"),
434     FEATURE_ENTRY(VIRTIO_IOMMU_F_MMIO, \
435             "VIRTIO_IOMMU_F_MMIO: VIRTIO_IOMMU_MAP_F_MMIO flag available"),
436     FEATURE_ENTRY(VIRTIO_IOMMU_F_BYPASS_CONFIG, \
437             "VIRTIO_IOMMU_F_BYPASS_CONFIG: Bypass field of IOMMU config "
438             "available"),
439     { -1, "" }
440 };
441 
442 /* virtio-mem features mapping */
443 qmp_virtio_feature_map_t virtio_mem_feature_map[] = {
444 #ifndef CONFIG_ACPI
445     FEATURE_ENTRY(VIRTIO_MEM_F_ACPI_PXM, \
446             "VIRTIO_MEM_F_ACPI_PXM: node_id is an ACPI PXM and is valid"),
447 #endif /* !CONFIG_ACPI */
448     FEATURE_ENTRY(VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE, \
449             "VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE: Unplugged memory cannot be "
450             "accessed"),
451     { -1, "" }
452 };
453 
454 /* virtio-rng features mapping */
455 qmp_virtio_feature_map_t virtio_rng_feature_map[] = {
456     FEATURE_ENTRY(VHOST_F_LOG_ALL, \
457             "VHOST_F_LOG_ALL: Logging write descriptors supported"),
458     FEATURE_ENTRY(VHOST_USER_F_PROTOCOL_FEATURES, \
459             "VHOST_USER_F_PROTOCOL_FEATURES: Vhost-user protocol features "
460             "negotiation supported"),
461     { -1, "" }
462 };
463 
464 /*
465  * The alignment to use between consumer and producer parts of vring.
466  * x86 pagesize again. This is the default, used by transports like PCI
467  * which don't provide a means for the guest to tell the host the alignment.
468  */
469 #define VIRTIO_PCI_VRING_ALIGN         4096
470 
471 typedef struct VRingDesc
472 {
473     uint64_t addr;
474     uint32_t len;
475     uint16_t flags;
476     uint16_t next;
477 } VRingDesc;
478 
479 typedef struct VRingPackedDesc {
480     uint64_t addr;
481     uint32_t len;
482     uint16_t id;
483     uint16_t flags;
484 } VRingPackedDesc;
485 
486 typedef struct VRingAvail
487 {
488     uint16_t flags;
489     uint16_t idx;
490     uint16_t ring[];
491 } VRingAvail;
492 
493 typedef struct VRingUsedElem
494 {
495     uint32_t id;
496     uint32_t len;
497 } VRingUsedElem;
498 
499 typedef struct VRingUsed
500 {
501     uint16_t flags;
502     uint16_t idx;
503     VRingUsedElem ring[];
504 } VRingUsed;
505 
506 typedef struct VRingMemoryRegionCaches {
507     struct rcu_head rcu;
508     MemoryRegionCache desc;
509     MemoryRegionCache avail;
510     MemoryRegionCache used;
511 } VRingMemoryRegionCaches;
512 
513 typedef struct VRing
514 {
515     unsigned int num;
516     unsigned int num_default;
517     unsigned int align;
518     hwaddr desc;
519     hwaddr avail;
520     hwaddr used;
521     VRingMemoryRegionCaches *caches;
522 } VRing;
523 
524 typedef struct VRingPackedDescEvent {
525     uint16_t off_wrap;
526     uint16_t flags;
527 } VRingPackedDescEvent ;
528 
529 struct VirtQueue
530 {
531     VRing vring;
532     VirtQueueElement *used_elems;
533 
534     /* Next head to pop */
535     uint16_t last_avail_idx;
536     bool last_avail_wrap_counter;
537 
538     /* Last avail_idx read from VQ. */
539     uint16_t shadow_avail_idx;
540     bool shadow_avail_wrap_counter;
541 
542     uint16_t used_idx;
543     bool used_wrap_counter;
544 
545     /* Last used index value we have signalled on */
546     uint16_t signalled_used;
547 
548     /* Last used index value we have signalled on */
549     bool signalled_used_valid;
550 
551     /* Notification enabled? */
552     bool notification;
553 
554     uint16_t queue_index;
555 
556     unsigned int inuse;
557 
558     uint16_t vector;
559     VirtIOHandleOutput handle_output;
560     VirtIODevice *vdev;
561     EventNotifier guest_notifier;
562     EventNotifier host_notifier;
563     bool host_notifier_enabled;
564     QLIST_ENTRY(VirtQueue) node;
565 };
566 
567 const char *virtio_device_names[] = {
568     [VIRTIO_ID_NET] = "virtio-net",
569     [VIRTIO_ID_BLOCK] = "virtio-blk",
570     [VIRTIO_ID_CONSOLE] = "virtio-serial",
571     [VIRTIO_ID_RNG] = "virtio-rng",
572     [VIRTIO_ID_BALLOON] = "virtio-balloon",
573     [VIRTIO_ID_IOMEM] = "virtio-iomem",
574     [VIRTIO_ID_RPMSG] = "virtio-rpmsg",
575     [VIRTIO_ID_SCSI] = "virtio-scsi",
576     [VIRTIO_ID_9P] = "virtio-9p",
577     [VIRTIO_ID_MAC80211_WLAN] = "virtio-mac-wlan",
578     [VIRTIO_ID_RPROC_SERIAL] = "virtio-rproc-serial",
579     [VIRTIO_ID_CAIF] = "virtio-caif",
580     [VIRTIO_ID_MEMORY_BALLOON] = "virtio-mem-balloon",
581     [VIRTIO_ID_GPU] = "virtio-gpu",
582     [VIRTIO_ID_CLOCK] = "virtio-clk",
583     [VIRTIO_ID_INPUT] = "virtio-input",
584     [VIRTIO_ID_VSOCK] = "vhost-vsock",
585     [VIRTIO_ID_CRYPTO] = "virtio-crypto",
586     [VIRTIO_ID_SIGNAL_DIST] = "virtio-signal",
587     [VIRTIO_ID_PSTORE] = "virtio-pstore",
588     [VIRTIO_ID_IOMMU] = "virtio-iommu",
589     [VIRTIO_ID_MEM] = "virtio-mem",
590     [VIRTIO_ID_SOUND] = "virtio-sound",
591     [VIRTIO_ID_FS] = "virtio-user-fs",
592     [VIRTIO_ID_PMEM] = "virtio-pmem",
593     [VIRTIO_ID_RPMB] = "virtio-rpmb",
594     [VIRTIO_ID_MAC80211_HWSIM] = "virtio-mac-hwsim",
595     [VIRTIO_ID_VIDEO_ENCODER] = "virtio-vid-encoder",
596     [VIRTIO_ID_VIDEO_DECODER] = "virtio-vid-decoder",
597     [VIRTIO_ID_SCMI] = "virtio-scmi",
598     [VIRTIO_ID_NITRO_SEC_MOD] = "virtio-nitro-sec-mod",
599     [VIRTIO_ID_I2C_ADAPTER] = "vhost-user-i2c",
600     [VIRTIO_ID_WATCHDOG] = "virtio-watchdog",
601     [VIRTIO_ID_CAN] = "virtio-can",
602     [VIRTIO_ID_DMABUF] = "virtio-dmabuf",
603     [VIRTIO_ID_PARAM_SERV] = "virtio-param-serv",
604     [VIRTIO_ID_AUDIO_POLICY] = "virtio-audio-pol",
605     [VIRTIO_ID_BT] = "virtio-bluetooth",
606     [VIRTIO_ID_GPIO] = "virtio-gpio"
607 };
608 
609 static const char *virtio_id_to_name(uint16_t device_id)
610 {
611     assert(device_id < G_N_ELEMENTS(virtio_device_names));
612     const char *name = virtio_device_names[device_id];
613     assert(name != NULL);
614     return name;
615 }
616 
617 /* Called within call_rcu().  */
618 static void virtio_free_region_cache(VRingMemoryRegionCaches *caches)
619 {
620     assert(caches != NULL);
621     address_space_cache_destroy(&caches->desc);
622     address_space_cache_destroy(&caches->avail);
623     address_space_cache_destroy(&caches->used);
624     g_free(caches);
625 }
626 
627 static void virtio_virtqueue_reset_region_cache(struct VirtQueue *vq)
628 {
629     VRingMemoryRegionCaches *caches;
630 
631     caches = qatomic_read(&vq->vring.caches);
632     qatomic_rcu_set(&vq->vring.caches, NULL);
633     if (caches) {
634         call_rcu(caches, virtio_free_region_cache, rcu);
635     }
636 }
637 
638 static void virtio_init_region_cache(VirtIODevice *vdev, int n)
639 {
640     VirtQueue *vq = &vdev->vq[n];
641     VRingMemoryRegionCaches *old = vq->vring.caches;
642     VRingMemoryRegionCaches *new = NULL;
643     hwaddr addr, size;
644     int64_t len;
645     bool packed;
646 
647 
648     addr = vq->vring.desc;
649     if (!addr) {
650         goto out_no_cache;
651     }
652     new = g_new0(VRingMemoryRegionCaches, 1);
653     size = virtio_queue_get_desc_size(vdev, n);
654     packed = virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED) ?
655                                    true : false;
656     len = address_space_cache_init(&new->desc, vdev->dma_as,
657                                    addr, size, packed);
658     if (len < size) {
659         virtio_error(vdev, "Cannot map desc");
660         goto err_desc;
661     }
662 
663     size = virtio_queue_get_used_size(vdev, n);
664     len = address_space_cache_init(&new->used, vdev->dma_as,
665                                    vq->vring.used, size, true);
666     if (len < size) {
667         virtio_error(vdev, "Cannot map used");
668         goto err_used;
669     }
670 
671     size = virtio_queue_get_avail_size(vdev, n);
672     len = address_space_cache_init(&new->avail, vdev->dma_as,
673                                    vq->vring.avail, size, false);
674     if (len < size) {
675         virtio_error(vdev, "Cannot map avail");
676         goto err_avail;
677     }
678 
679     qatomic_rcu_set(&vq->vring.caches, new);
680     if (old) {
681         call_rcu(old, virtio_free_region_cache, rcu);
682     }
683     return;
684 
685 err_avail:
686     address_space_cache_destroy(&new->avail);
687 err_used:
688     address_space_cache_destroy(&new->used);
689 err_desc:
690     address_space_cache_destroy(&new->desc);
691 out_no_cache:
692     g_free(new);
693     virtio_virtqueue_reset_region_cache(vq);
694 }
695 
696 /* virt queue functions */
697 void virtio_queue_update_rings(VirtIODevice *vdev, int n)
698 {
699     VRing *vring = &vdev->vq[n].vring;
700 
701     if (!vring->num || !vring->desc || !vring->align) {
702         /* not yet setup -> nothing to do */
703         return;
704     }
705     vring->avail = vring->desc + vring->num * sizeof(VRingDesc);
706     vring->used = vring_align(vring->avail +
707                               offsetof(VRingAvail, ring[vring->num]),
708                               vring->align);
709     virtio_init_region_cache(vdev, n);
710 }
711 
712 /* Called within rcu_read_lock().  */
713 static void vring_split_desc_read(VirtIODevice *vdev, VRingDesc *desc,
714                                   MemoryRegionCache *cache, int i)
715 {
716     address_space_read_cached(cache, i * sizeof(VRingDesc),
717                               desc, sizeof(VRingDesc));
718     virtio_tswap64s(vdev, &desc->addr);
719     virtio_tswap32s(vdev, &desc->len);
720     virtio_tswap16s(vdev, &desc->flags);
721     virtio_tswap16s(vdev, &desc->next);
722 }
723 
724 static void vring_packed_event_read(VirtIODevice *vdev,
725                                     MemoryRegionCache *cache,
726                                     VRingPackedDescEvent *e)
727 {
728     hwaddr off_off = offsetof(VRingPackedDescEvent, off_wrap);
729     hwaddr off_flags = offsetof(VRingPackedDescEvent, flags);
730 
731     e->flags = virtio_lduw_phys_cached(vdev, cache, off_flags);
732     /* Make sure flags is seen before off_wrap */
733     smp_rmb();
734     e->off_wrap = virtio_lduw_phys_cached(vdev, cache, off_off);
735     virtio_tswap16s(vdev, &e->flags);
736 }
737 
738 static void vring_packed_off_wrap_write(VirtIODevice *vdev,
739                                         MemoryRegionCache *cache,
740                                         uint16_t off_wrap)
741 {
742     hwaddr off = offsetof(VRingPackedDescEvent, off_wrap);
743 
744     virtio_stw_phys_cached(vdev, cache, off, off_wrap);
745     address_space_cache_invalidate(cache, off, sizeof(off_wrap));
746 }
747 
748 static void vring_packed_flags_write(VirtIODevice *vdev,
749                                      MemoryRegionCache *cache, uint16_t flags)
750 {
751     hwaddr off = offsetof(VRingPackedDescEvent, flags);
752 
753     virtio_stw_phys_cached(vdev, cache, off, flags);
754     address_space_cache_invalidate(cache, off, sizeof(flags));
755 }
756 
757 /* Called within rcu_read_lock().  */
758 static VRingMemoryRegionCaches *vring_get_region_caches(struct VirtQueue *vq)
759 {
760     return qatomic_rcu_read(&vq->vring.caches);
761 }
762 
763 /* Called within rcu_read_lock().  */
764 static inline uint16_t vring_avail_flags(VirtQueue *vq)
765 {
766     VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
767     hwaddr pa = offsetof(VRingAvail, flags);
768 
769     if (!caches) {
770         return 0;
771     }
772 
773     return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
774 }
775 
776 /* Called within rcu_read_lock().  */
777 static inline uint16_t vring_avail_idx(VirtQueue *vq)
778 {
779     VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
780     hwaddr pa = offsetof(VRingAvail, idx);
781 
782     if (!caches) {
783         return 0;
784     }
785 
786     vq->shadow_avail_idx = virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
787     return vq->shadow_avail_idx;
788 }
789 
790 /* Called within rcu_read_lock().  */
791 static inline uint16_t vring_avail_ring(VirtQueue *vq, int i)
792 {
793     VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
794     hwaddr pa = offsetof(VRingAvail, ring[i]);
795 
796     if (!caches) {
797         return 0;
798     }
799 
800     return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
801 }
802 
803 /* Called within rcu_read_lock().  */
804 static inline uint16_t vring_get_used_event(VirtQueue *vq)
805 {
806     return vring_avail_ring(vq, vq->vring.num);
807 }
808 
809 /* Called within rcu_read_lock().  */
810 static inline void vring_used_write(VirtQueue *vq, VRingUsedElem *uelem,
811                                     int i)
812 {
813     VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
814     hwaddr pa = offsetof(VRingUsed, ring[i]);
815 
816     if (!caches) {
817         return;
818     }
819 
820     virtio_tswap32s(vq->vdev, &uelem->id);
821     virtio_tswap32s(vq->vdev, &uelem->len);
822     address_space_write_cached(&caches->used, pa, uelem, sizeof(VRingUsedElem));
823     address_space_cache_invalidate(&caches->used, pa, sizeof(VRingUsedElem));
824 }
825 
826 /* Called within rcu_read_lock(). */
827 static inline uint16_t vring_used_flags(VirtQueue *vq)
828 {
829     VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
830     hwaddr pa = offsetof(VRingUsed, flags);
831 
832     if (!caches) {
833         return 0;
834     }
835 
836     return virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
837 }
838 
839 /* Called within rcu_read_lock().  */
840 static uint16_t vring_used_idx(VirtQueue *vq)
841 {
842     VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
843     hwaddr pa = offsetof(VRingUsed, idx);
844 
845     if (!caches) {
846         return 0;
847     }
848 
849     return virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
850 }
851 
852 /* Called within rcu_read_lock().  */
853 static inline void vring_used_idx_set(VirtQueue *vq, uint16_t val)
854 {
855     VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
856     hwaddr pa = offsetof(VRingUsed, idx);
857 
858     if (caches) {
859         virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val);
860         address_space_cache_invalidate(&caches->used, pa, sizeof(val));
861     }
862 
863     vq->used_idx = val;
864 }
865 
866 /* Called within rcu_read_lock().  */
867 static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask)
868 {
869     VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
870     VirtIODevice *vdev = vq->vdev;
871     hwaddr pa = offsetof(VRingUsed, flags);
872     uint16_t flags;
873 
874     if (!caches) {
875         return;
876     }
877 
878     flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
879     virtio_stw_phys_cached(vdev, &caches->used, pa, flags | mask);
880     address_space_cache_invalidate(&caches->used, pa, sizeof(flags));
881 }
882 
883 /* Called within rcu_read_lock().  */
884 static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask)
885 {
886     VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
887     VirtIODevice *vdev = vq->vdev;
888     hwaddr pa = offsetof(VRingUsed, flags);
889     uint16_t flags;
890 
891     if (!caches) {
892         return;
893     }
894 
895     flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
896     virtio_stw_phys_cached(vdev, &caches->used, pa, flags & ~mask);
897     address_space_cache_invalidate(&caches->used, pa, sizeof(flags));
898 }
899 
900 /* Called within rcu_read_lock().  */
901 static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val)
902 {
903     VRingMemoryRegionCaches *caches;
904     hwaddr pa;
905     if (!vq->notification) {
906         return;
907     }
908 
909     caches = vring_get_region_caches(vq);
910     if (!caches) {
911         return;
912     }
913 
914     pa = offsetof(VRingUsed, ring[vq->vring.num]);
915     virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val);
916     address_space_cache_invalidate(&caches->used, pa, sizeof(val));
917 }
918 
919 static void virtio_queue_split_set_notification(VirtQueue *vq, int enable)
920 {
921     RCU_READ_LOCK_GUARD();
922 
923     if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
924         vring_set_avail_event(vq, vring_avail_idx(vq));
925     } else if (enable) {
926         vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY);
927     } else {
928         vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY);
929     }
930     if (enable) {
931         /* Expose avail event/used flags before caller checks the avail idx. */
932         smp_mb();
933     }
934 }
935 
936 static void virtio_queue_packed_set_notification(VirtQueue *vq, int enable)
937 {
938     uint16_t off_wrap;
939     VRingPackedDescEvent e;
940     VRingMemoryRegionCaches *caches;
941 
942     RCU_READ_LOCK_GUARD();
943     caches = vring_get_region_caches(vq);
944     if (!caches) {
945         return;
946     }
947 
948     vring_packed_event_read(vq->vdev, &caches->used, &e);
949 
950     if (!enable) {
951         e.flags = VRING_PACKED_EVENT_FLAG_DISABLE;
952     } else if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
953         off_wrap = vq->shadow_avail_idx | vq->shadow_avail_wrap_counter << 15;
954         vring_packed_off_wrap_write(vq->vdev, &caches->used, off_wrap);
955         /* Make sure off_wrap is wrote before flags */
956         smp_wmb();
957         e.flags = VRING_PACKED_EVENT_FLAG_DESC;
958     } else {
959         e.flags = VRING_PACKED_EVENT_FLAG_ENABLE;
960     }
961 
962     vring_packed_flags_write(vq->vdev, &caches->used, e.flags);
963     if (enable) {
964         /* Expose avail event/used flags before caller checks the avail idx. */
965         smp_mb();
966     }
967 }
968 
969 bool virtio_queue_get_notification(VirtQueue *vq)
970 {
971     return vq->notification;
972 }
973 
974 void virtio_queue_set_notification(VirtQueue *vq, int enable)
975 {
976     vq->notification = enable;
977 
978     if (!vq->vring.desc) {
979         return;
980     }
981 
982     if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
983         virtio_queue_packed_set_notification(vq, enable);
984     } else {
985         virtio_queue_split_set_notification(vq, enable);
986     }
987 }
988 
989 int virtio_queue_ready(VirtQueue *vq)
990 {
991     return vq->vring.avail != 0;
992 }
993 
994 static void vring_packed_desc_read_flags(VirtIODevice *vdev,
995                                          uint16_t *flags,
996                                          MemoryRegionCache *cache,
997                                          int i)
998 {
999     hwaddr off = i * sizeof(VRingPackedDesc) + offsetof(VRingPackedDesc, flags);
1000 
1001     *flags = virtio_lduw_phys_cached(vdev, cache, off);
1002 }
1003 
1004 static void vring_packed_desc_read(VirtIODevice *vdev,
1005                                    VRingPackedDesc *desc,
1006                                    MemoryRegionCache *cache,
1007                                    int i, bool strict_order)
1008 {
1009     hwaddr off = i * sizeof(VRingPackedDesc);
1010 
1011     vring_packed_desc_read_flags(vdev, &desc->flags, cache, i);
1012 
1013     if (strict_order) {
1014         /* Make sure flags is read before the rest fields. */
1015         smp_rmb();
1016     }
1017 
1018     address_space_read_cached(cache, off + offsetof(VRingPackedDesc, addr),
1019                               &desc->addr, sizeof(desc->addr));
1020     address_space_read_cached(cache, off + offsetof(VRingPackedDesc, id),
1021                               &desc->id, sizeof(desc->id));
1022     address_space_read_cached(cache, off + offsetof(VRingPackedDesc, len),
1023                               &desc->len, sizeof(desc->len));
1024     virtio_tswap64s(vdev, &desc->addr);
1025     virtio_tswap16s(vdev, &desc->id);
1026     virtio_tswap32s(vdev, &desc->len);
1027 }
1028 
1029 static void vring_packed_desc_write_data(VirtIODevice *vdev,
1030                                          VRingPackedDesc *desc,
1031                                          MemoryRegionCache *cache,
1032                                          int i)
1033 {
1034     hwaddr off_id = i * sizeof(VRingPackedDesc) +
1035                     offsetof(VRingPackedDesc, id);
1036     hwaddr off_len = i * sizeof(VRingPackedDesc) +
1037                     offsetof(VRingPackedDesc, len);
1038 
1039     virtio_tswap32s(vdev, &desc->len);
1040     virtio_tswap16s(vdev, &desc->id);
1041     address_space_write_cached(cache, off_id, &desc->id, sizeof(desc->id));
1042     address_space_cache_invalidate(cache, off_id, sizeof(desc->id));
1043     address_space_write_cached(cache, off_len, &desc->len, sizeof(desc->len));
1044     address_space_cache_invalidate(cache, off_len, sizeof(desc->len));
1045 }
1046 
1047 static void vring_packed_desc_write_flags(VirtIODevice *vdev,
1048                                           VRingPackedDesc *desc,
1049                                           MemoryRegionCache *cache,
1050                                           int i)
1051 {
1052     hwaddr off = i * sizeof(VRingPackedDesc) + offsetof(VRingPackedDesc, flags);
1053 
1054     virtio_stw_phys_cached(vdev, cache, off, desc->flags);
1055     address_space_cache_invalidate(cache, off, sizeof(desc->flags));
1056 }
1057 
1058 static void vring_packed_desc_write(VirtIODevice *vdev,
1059                                     VRingPackedDesc *desc,
1060                                     MemoryRegionCache *cache,
1061                                     int i, bool strict_order)
1062 {
1063     vring_packed_desc_write_data(vdev, desc, cache, i);
1064     if (strict_order) {
1065         /* Make sure data is wrote before flags. */
1066         smp_wmb();
1067     }
1068     vring_packed_desc_write_flags(vdev, desc, cache, i);
1069 }
1070 
1071 static inline bool is_desc_avail(uint16_t flags, bool wrap_counter)
1072 {
1073     bool avail, used;
1074 
1075     avail = !!(flags & (1 << VRING_PACKED_DESC_F_AVAIL));
1076     used = !!(flags & (1 << VRING_PACKED_DESC_F_USED));
1077     return (avail != used) && (avail == wrap_counter);
1078 }
1079 
1080 /* Fetch avail_idx from VQ memory only when we really need to know if
1081  * guest has added some buffers.
1082  * Called within rcu_read_lock().  */
1083 static int virtio_queue_empty_rcu(VirtQueue *vq)
1084 {
1085     if (virtio_device_disabled(vq->vdev)) {
1086         return 1;
1087     }
1088 
1089     if (unlikely(!vq->vring.avail)) {
1090         return 1;
1091     }
1092 
1093     if (vq->shadow_avail_idx != vq->last_avail_idx) {
1094         return 0;
1095     }
1096 
1097     return vring_avail_idx(vq) == vq->last_avail_idx;
1098 }
1099 
1100 static int virtio_queue_split_empty(VirtQueue *vq)
1101 {
1102     bool empty;
1103 
1104     if (virtio_device_disabled(vq->vdev)) {
1105         return 1;
1106     }
1107 
1108     if (unlikely(!vq->vring.avail)) {
1109         return 1;
1110     }
1111 
1112     if (vq->shadow_avail_idx != vq->last_avail_idx) {
1113         return 0;
1114     }
1115 
1116     RCU_READ_LOCK_GUARD();
1117     empty = vring_avail_idx(vq) == vq->last_avail_idx;
1118     return empty;
1119 }
1120 
1121 /* Called within rcu_read_lock().  */
1122 static int virtio_queue_packed_empty_rcu(VirtQueue *vq)
1123 {
1124     struct VRingPackedDesc desc;
1125     VRingMemoryRegionCaches *cache;
1126 
1127     if (unlikely(!vq->vring.desc)) {
1128         return 1;
1129     }
1130 
1131     cache = vring_get_region_caches(vq);
1132     if (!cache) {
1133         return 1;
1134     }
1135 
1136     vring_packed_desc_read_flags(vq->vdev, &desc.flags, &cache->desc,
1137                                  vq->last_avail_idx);
1138 
1139     return !is_desc_avail(desc.flags, vq->last_avail_wrap_counter);
1140 }
1141 
1142 static int virtio_queue_packed_empty(VirtQueue *vq)
1143 {
1144     RCU_READ_LOCK_GUARD();
1145     return virtio_queue_packed_empty_rcu(vq);
1146 }
1147 
1148 int virtio_queue_empty(VirtQueue *vq)
1149 {
1150     if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
1151         return virtio_queue_packed_empty(vq);
1152     } else {
1153         return virtio_queue_split_empty(vq);
1154     }
1155 }
1156 
1157 static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem,
1158                                unsigned int len)
1159 {
1160     AddressSpace *dma_as = vq->vdev->dma_as;
1161     unsigned int offset;
1162     int i;
1163 
1164     offset = 0;
1165     for (i = 0; i < elem->in_num; i++) {
1166         size_t size = MIN(len - offset, elem->in_sg[i].iov_len);
1167 
1168         dma_memory_unmap(dma_as, elem->in_sg[i].iov_base,
1169                          elem->in_sg[i].iov_len,
1170                          DMA_DIRECTION_FROM_DEVICE, size);
1171 
1172         offset += size;
1173     }
1174 
1175     for (i = 0; i < elem->out_num; i++)
1176         dma_memory_unmap(dma_as, elem->out_sg[i].iov_base,
1177                          elem->out_sg[i].iov_len,
1178                          DMA_DIRECTION_TO_DEVICE,
1179                          elem->out_sg[i].iov_len);
1180 }
1181 
1182 /* virtqueue_detach_element:
1183  * @vq: The #VirtQueue
1184  * @elem: The #VirtQueueElement
1185  * @len: number of bytes written
1186  *
1187  * Detach the element from the virtqueue.  This function is suitable for device
1188  * reset or other situations where a #VirtQueueElement is simply freed and will
1189  * not be pushed or discarded.
1190  */
1191 void virtqueue_detach_element(VirtQueue *vq, const VirtQueueElement *elem,
1192                               unsigned int len)
1193 {
1194     vq->inuse -= elem->ndescs;
1195     virtqueue_unmap_sg(vq, elem, len);
1196 }
1197 
1198 static void virtqueue_split_rewind(VirtQueue *vq, unsigned int num)
1199 {
1200     vq->last_avail_idx -= num;
1201 }
1202 
1203 static void virtqueue_packed_rewind(VirtQueue *vq, unsigned int num)
1204 {
1205     if (vq->last_avail_idx < num) {
1206         vq->last_avail_idx = vq->vring.num + vq->last_avail_idx - num;
1207         vq->last_avail_wrap_counter ^= 1;
1208     } else {
1209         vq->last_avail_idx -= num;
1210     }
1211 }
1212 
1213 /* virtqueue_unpop:
1214  * @vq: The #VirtQueue
1215  * @elem: The #VirtQueueElement
1216  * @len: number of bytes written
1217  *
1218  * Pretend the most recent element wasn't popped from the virtqueue.  The next
1219  * call to virtqueue_pop() will refetch the element.
1220  */
1221 void virtqueue_unpop(VirtQueue *vq, const VirtQueueElement *elem,
1222                      unsigned int len)
1223 {
1224 
1225     if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
1226         virtqueue_packed_rewind(vq, 1);
1227     } else {
1228         virtqueue_split_rewind(vq, 1);
1229     }
1230 
1231     virtqueue_detach_element(vq, elem, len);
1232 }
1233 
1234 /* virtqueue_rewind:
1235  * @vq: The #VirtQueue
1236  * @num: Number of elements to push back
1237  *
1238  * Pretend that elements weren't popped from the virtqueue.  The next
1239  * virtqueue_pop() will refetch the oldest element.
1240  *
1241  * Use virtqueue_unpop() instead if you have a VirtQueueElement.
1242  *
1243  * Returns: true on success, false if @num is greater than the number of in use
1244  * elements.
1245  */
1246 bool virtqueue_rewind(VirtQueue *vq, unsigned int num)
1247 {
1248     if (num > vq->inuse) {
1249         return false;
1250     }
1251 
1252     vq->inuse -= num;
1253     if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
1254         virtqueue_packed_rewind(vq, num);
1255     } else {
1256         virtqueue_split_rewind(vq, num);
1257     }
1258     return true;
1259 }
1260 
1261 static void virtqueue_split_fill(VirtQueue *vq, const VirtQueueElement *elem,
1262                     unsigned int len, unsigned int idx)
1263 {
1264     VRingUsedElem uelem;
1265 
1266     if (unlikely(!vq->vring.used)) {
1267         return;
1268     }
1269 
1270     idx = (idx + vq->used_idx) % vq->vring.num;
1271 
1272     uelem.id = elem->index;
1273     uelem.len = len;
1274     vring_used_write(vq, &uelem, idx);
1275 }
1276 
1277 static void virtqueue_packed_fill(VirtQueue *vq, const VirtQueueElement *elem,
1278                                   unsigned int len, unsigned int idx)
1279 {
1280     vq->used_elems[idx].index = elem->index;
1281     vq->used_elems[idx].len = len;
1282     vq->used_elems[idx].ndescs = elem->ndescs;
1283 }
1284 
1285 static void virtqueue_packed_fill_desc(VirtQueue *vq,
1286                                        const VirtQueueElement *elem,
1287                                        unsigned int idx,
1288                                        bool strict_order)
1289 {
1290     uint16_t head;
1291     VRingMemoryRegionCaches *caches;
1292     VRingPackedDesc desc = {
1293         .id = elem->index,
1294         .len = elem->len,
1295     };
1296     bool wrap_counter = vq->used_wrap_counter;
1297 
1298     if (unlikely(!vq->vring.desc)) {
1299         return;
1300     }
1301 
1302     head = vq->used_idx + idx;
1303     if (head >= vq->vring.num) {
1304         head -= vq->vring.num;
1305         wrap_counter ^= 1;
1306     }
1307     if (wrap_counter) {
1308         desc.flags |= (1 << VRING_PACKED_DESC_F_AVAIL);
1309         desc.flags |= (1 << VRING_PACKED_DESC_F_USED);
1310     } else {
1311         desc.flags &= ~(1 << VRING_PACKED_DESC_F_AVAIL);
1312         desc.flags &= ~(1 << VRING_PACKED_DESC_F_USED);
1313     }
1314 
1315     caches = vring_get_region_caches(vq);
1316     if (!caches) {
1317         return;
1318     }
1319 
1320     vring_packed_desc_write(vq->vdev, &desc, &caches->desc, head, strict_order);
1321 }
1322 
1323 /* Called within rcu_read_lock().  */
1324 void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
1325                     unsigned int len, unsigned int idx)
1326 {
1327     trace_virtqueue_fill(vq, elem, len, idx);
1328 
1329     virtqueue_unmap_sg(vq, elem, len);
1330 
1331     if (virtio_device_disabled(vq->vdev)) {
1332         return;
1333     }
1334 
1335     if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
1336         virtqueue_packed_fill(vq, elem, len, idx);
1337     } else {
1338         virtqueue_split_fill(vq, elem, len, idx);
1339     }
1340 }
1341 
1342 /* Called within rcu_read_lock().  */
1343 static void virtqueue_split_flush(VirtQueue *vq, unsigned int count)
1344 {
1345     uint16_t old, new;
1346 
1347     if (unlikely(!vq->vring.used)) {
1348         return;
1349     }
1350 
1351     /* Make sure buffer is written before we update index. */
1352     smp_wmb();
1353     trace_virtqueue_flush(vq, count);
1354     old = vq->used_idx;
1355     new = old + count;
1356     vring_used_idx_set(vq, new);
1357     vq->inuse -= count;
1358     if (unlikely((int16_t)(new - vq->signalled_used) < (uint16_t)(new - old)))
1359         vq->signalled_used_valid = false;
1360 }
1361 
1362 static void virtqueue_packed_flush(VirtQueue *vq, unsigned int count)
1363 {
1364     unsigned int i, ndescs = 0;
1365 
1366     if (unlikely(!vq->vring.desc)) {
1367         return;
1368     }
1369 
1370     for (i = 1; i < count; i++) {
1371         virtqueue_packed_fill_desc(vq, &vq->used_elems[i], i, false);
1372         ndescs += vq->used_elems[i].ndescs;
1373     }
1374     virtqueue_packed_fill_desc(vq, &vq->used_elems[0], 0, true);
1375     ndescs += vq->used_elems[0].ndescs;
1376 
1377     vq->inuse -= ndescs;
1378     vq->used_idx += ndescs;
1379     if (vq->used_idx >= vq->vring.num) {
1380         vq->used_idx -= vq->vring.num;
1381         vq->used_wrap_counter ^= 1;
1382         vq->signalled_used_valid = false;
1383     }
1384 }
1385 
1386 void virtqueue_flush(VirtQueue *vq, unsigned int count)
1387 {
1388     if (virtio_device_disabled(vq->vdev)) {
1389         vq->inuse -= count;
1390         return;
1391     }
1392 
1393     if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
1394         virtqueue_packed_flush(vq, count);
1395     } else {
1396         virtqueue_split_flush(vq, count);
1397     }
1398 }
1399 
1400 void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
1401                     unsigned int len)
1402 {
1403     RCU_READ_LOCK_GUARD();
1404     virtqueue_fill(vq, elem, len, 0);
1405     virtqueue_flush(vq, 1);
1406 }
1407 
1408 /* Called within rcu_read_lock().  */
1409 static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx)
1410 {
1411     uint16_t num_heads = vring_avail_idx(vq) - idx;
1412 
1413     /* Check it isn't doing very strange things with descriptor numbers. */
1414     if (num_heads > vq->vring.num) {
1415         virtio_error(vq->vdev, "Guest moved used index from %u to %u",
1416                      idx, vq->shadow_avail_idx);
1417         return -EINVAL;
1418     }
1419     /* On success, callers read a descriptor at vq->last_avail_idx.
1420      * Make sure descriptor read does not bypass avail index read. */
1421     if (num_heads) {
1422         smp_rmb();
1423     }
1424 
1425     return num_heads;
1426 }
1427 
1428 /* Called within rcu_read_lock().  */
1429 static bool virtqueue_get_head(VirtQueue *vq, unsigned int idx,
1430                                unsigned int *head)
1431 {
1432     /* Grab the next descriptor number they're advertising, and increment
1433      * the index we've seen. */
1434     *head = vring_avail_ring(vq, idx % vq->vring.num);
1435 
1436     /* If their number is silly, that's a fatal mistake. */
1437     if (*head >= vq->vring.num) {
1438         virtio_error(vq->vdev, "Guest says index %u is available", *head);
1439         return false;
1440     }
1441 
1442     return true;
1443 }
1444 
1445 enum {
1446     VIRTQUEUE_READ_DESC_ERROR = -1,
1447     VIRTQUEUE_READ_DESC_DONE = 0,   /* end of chain */
1448     VIRTQUEUE_READ_DESC_MORE = 1,   /* more buffers in chain */
1449 };
1450 
1451 static int virtqueue_split_read_next_desc(VirtIODevice *vdev, VRingDesc *desc,
1452                                           MemoryRegionCache *desc_cache,
1453                                           unsigned int max, unsigned int *next)
1454 {
1455     /* If this descriptor says it doesn't chain, we're done. */
1456     if (!(desc->flags & VRING_DESC_F_NEXT)) {
1457         return VIRTQUEUE_READ_DESC_DONE;
1458     }
1459 
1460     /* Check they're not leading us off end of descriptors. */
1461     *next = desc->next;
1462     /* Make sure compiler knows to grab that: we don't want it changing! */
1463     smp_wmb();
1464 
1465     if (*next >= max) {
1466         virtio_error(vdev, "Desc next is %u", *next);
1467         return VIRTQUEUE_READ_DESC_ERROR;
1468     }
1469 
1470     vring_split_desc_read(vdev, desc, desc_cache, *next);
1471     return VIRTQUEUE_READ_DESC_MORE;
1472 }
1473 
1474 /* Called within rcu_read_lock().  */
1475 static void virtqueue_split_get_avail_bytes(VirtQueue *vq,
1476                             unsigned int *in_bytes, unsigned int *out_bytes,
1477                             unsigned max_in_bytes, unsigned max_out_bytes,
1478                             VRingMemoryRegionCaches *caches)
1479 {
1480     VirtIODevice *vdev = vq->vdev;
1481     unsigned int max, idx;
1482     unsigned int total_bufs, in_total, out_total;
1483     MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
1484     int64_t len = 0;
1485     int rc;
1486 
1487     idx = vq->last_avail_idx;
1488     total_bufs = in_total = out_total = 0;
1489 
1490     max = vq->vring.num;
1491 
1492     while ((rc = virtqueue_num_heads(vq, idx)) > 0) {
1493         MemoryRegionCache *desc_cache = &caches->desc;
1494         unsigned int num_bufs;
1495         VRingDesc desc;
1496         unsigned int i;
1497 
1498         num_bufs = total_bufs;
1499 
1500         if (!virtqueue_get_head(vq, idx++, &i)) {
1501             goto err;
1502         }
1503 
1504         vring_split_desc_read(vdev, &desc, desc_cache, i);
1505 
1506         if (desc.flags & VRING_DESC_F_INDIRECT) {
1507             if (!desc.len || (desc.len % sizeof(VRingDesc))) {
1508                 virtio_error(vdev, "Invalid size for indirect buffer table");
1509                 goto err;
1510             }
1511 
1512             /* If we've got too many, that implies a descriptor loop. */
1513             if (num_bufs >= max) {
1514                 virtio_error(vdev, "Looped descriptor");
1515                 goto err;
1516             }
1517 
1518             /* loop over the indirect descriptor table */
1519             len = address_space_cache_init(&indirect_desc_cache,
1520                                            vdev->dma_as,
1521                                            desc.addr, desc.len, false);
1522             desc_cache = &indirect_desc_cache;
1523             if (len < desc.len) {
1524                 virtio_error(vdev, "Cannot map indirect buffer");
1525                 goto err;
1526             }
1527 
1528             max = desc.len / sizeof(VRingDesc);
1529             num_bufs = i = 0;
1530             vring_split_desc_read(vdev, &desc, desc_cache, i);
1531         }
1532 
1533         do {
1534             /* If we've got too many, that implies a descriptor loop. */
1535             if (++num_bufs > max) {
1536                 virtio_error(vdev, "Looped descriptor");
1537                 goto err;
1538             }
1539 
1540             if (desc.flags & VRING_DESC_F_WRITE) {
1541                 in_total += desc.len;
1542             } else {
1543                 out_total += desc.len;
1544             }
1545             if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
1546                 goto done;
1547             }
1548 
1549             rc = virtqueue_split_read_next_desc(vdev, &desc, desc_cache, max, &i);
1550         } while (rc == VIRTQUEUE_READ_DESC_MORE);
1551 
1552         if (rc == VIRTQUEUE_READ_DESC_ERROR) {
1553             goto err;
1554         }
1555 
1556         if (desc_cache == &indirect_desc_cache) {
1557             address_space_cache_destroy(&indirect_desc_cache);
1558             total_bufs++;
1559         } else {
1560             total_bufs = num_bufs;
1561         }
1562     }
1563 
1564     if (rc < 0) {
1565         goto err;
1566     }
1567 
1568 done:
1569     address_space_cache_destroy(&indirect_desc_cache);
1570     if (in_bytes) {
1571         *in_bytes = in_total;
1572     }
1573     if (out_bytes) {
1574         *out_bytes = out_total;
1575     }
1576     return;
1577 
1578 err:
1579     in_total = out_total = 0;
1580     goto done;
1581 }
1582 
1583 static int virtqueue_packed_read_next_desc(VirtQueue *vq,
1584                                            VRingPackedDesc *desc,
1585                                            MemoryRegionCache
1586                                            *desc_cache,
1587                                            unsigned int max,
1588                                            unsigned int *next,
1589                                            bool indirect)
1590 {
1591     /* If this descriptor says it doesn't chain, we're done. */
1592     if (!indirect && !(desc->flags & VRING_DESC_F_NEXT)) {
1593         return VIRTQUEUE_READ_DESC_DONE;
1594     }
1595 
1596     ++*next;
1597     if (*next == max) {
1598         if (indirect) {
1599             return VIRTQUEUE_READ_DESC_DONE;
1600         } else {
1601             (*next) -= vq->vring.num;
1602         }
1603     }
1604 
1605     vring_packed_desc_read(vq->vdev, desc, desc_cache, *next, false);
1606     return VIRTQUEUE_READ_DESC_MORE;
1607 }
1608 
1609 /* Called within rcu_read_lock().  */
1610 static void virtqueue_packed_get_avail_bytes(VirtQueue *vq,
1611                                              unsigned int *in_bytes,
1612                                              unsigned int *out_bytes,
1613                                              unsigned max_in_bytes,
1614                                              unsigned max_out_bytes,
1615                                              VRingMemoryRegionCaches *caches)
1616 {
1617     VirtIODevice *vdev = vq->vdev;
1618     unsigned int max, idx;
1619     unsigned int total_bufs, in_total, out_total;
1620     MemoryRegionCache *desc_cache;
1621     MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
1622     int64_t len = 0;
1623     VRingPackedDesc desc;
1624     bool wrap_counter;
1625 
1626     idx = vq->last_avail_idx;
1627     wrap_counter = vq->last_avail_wrap_counter;
1628     total_bufs = in_total = out_total = 0;
1629 
1630     max = vq->vring.num;
1631 
1632     for (;;) {
1633         unsigned int num_bufs = total_bufs;
1634         unsigned int i = idx;
1635         int rc;
1636 
1637         desc_cache = &caches->desc;
1638         vring_packed_desc_read(vdev, &desc, desc_cache, idx, true);
1639         if (!is_desc_avail(desc.flags, wrap_counter)) {
1640             break;
1641         }
1642 
1643         if (desc.flags & VRING_DESC_F_INDIRECT) {
1644             if (desc.len % sizeof(VRingPackedDesc)) {
1645                 virtio_error(vdev, "Invalid size for indirect buffer table");
1646                 goto err;
1647             }
1648 
1649             /* If we've got too many, that implies a descriptor loop. */
1650             if (num_bufs >= max) {
1651                 virtio_error(vdev, "Looped descriptor");
1652                 goto err;
1653             }
1654 
1655             /* loop over the indirect descriptor table */
1656             len = address_space_cache_init(&indirect_desc_cache,
1657                                            vdev->dma_as,
1658                                            desc.addr, desc.len, false);
1659             desc_cache = &indirect_desc_cache;
1660             if (len < desc.len) {
1661                 virtio_error(vdev, "Cannot map indirect buffer");
1662                 goto err;
1663             }
1664 
1665             max = desc.len / sizeof(VRingPackedDesc);
1666             num_bufs = i = 0;
1667             vring_packed_desc_read(vdev, &desc, desc_cache, i, false);
1668         }
1669 
1670         do {
1671             /* If we've got too many, that implies a descriptor loop. */
1672             if (++num_bufs > max) {
1673                 virtio_error(vdev, "Looped descriptor");
1674                 goto err;
1675             }
1676 
1677             if (desc.flags & VRING_DESC_F_WRITE) {
1678                 in_total += desc.len;
1679             } else {
1680                 out_total += desc.len;
1681             }
1682             if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
1683                 goto done;
1684             }
1685 
1686             rc = virtqueue_packed_read_next_desc(vq, &desc, desc_cache, max,
1687                                                  &i, desc_cache ==
1688                                                  &indirect_desc_cache);
1689         } while (rc == VIRTQUEUE_READ_DESC_MORE);
1690 
1691         if (desc_cache == &indirect_desc_cache) {
1692             address_space_cache_destroy(&indirect_desc_cache);
1693             total_bufs++;
1694             idx++;
1695         } else {
1696             idx += num_bufs - total_bufs;
1697             total_bufs = num_bufs;
1698         }
1699 
1700         if (idx >= vq->vring.num) {
1701             idx -= vq->vring.num;
1702             wrap_counter ^= 1;
1703         }
1704     }
1705 
1706     /* Record the index and wrap counter for a kick we want */
1707     vq->shadow_avail_idx = idx;
1708     vq->shadow_avail_wrap_counter = wrap_counter;
1709 done:
1710     address_space_cache_destroy(&indirect_desc_cache);
1711     if (in_bytes) {
1712         *in_bytes = in_total;
1713     }
1714     if (out_bytes) {
1715         *out_bytes = out_total;
1716     }
1717     return;
1718 
1719 err:
1720     in_total = out_total = 0;
1721     goto done;
1722 }
1723 
1724 void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
1725                                unsigned int *out_bytes,
1726                                unsigned max_in_bytes, unsigned max_out_bytes)
1727 {
1728     uint16_t desc_size;
1729     VRingMemoryRegionCaches *caches;
1730 
1731     RCU_READ_LOCK_GUARD();
1732 
1733     if (unlikely(!vq->vring.desc)) {
1734         goto err;
1735     }
1736 
1737     caches = vring_get_region_caches(vq);
1738     if (!caches) {
1739         goto err;
1740     }
1741 
1742     desc_size = virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED) ?
1743                                 sizeof(VRingPackedDesc) : sizeof(VRingDesc);
1744     if (caches->desc.len < vq->vring.num * desc_size) {
1745         virtio_error(vq->vdev, "Cannot map descriptor ring");
1746         goto err;
1747     }
1748 
1749     if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
1750         virtqueue_packed_get_avail_bytes(vq, in_bytes, out_bytes,
1751                                          max_in_bytes, max_out_bytes,
1752                                          caches);
1753     } else {
1754         virtqueue_split_get_avail_bytes(vq, in_bytes, out_bytes,
1755                                         max_in_bytes, max_out_bytes,
1756                                         caches);
1757     }
1758 
1759     return;
1760 err:
1761     if (in_bytes) {
1762         *in_bytes = 0;
1763     }
1764     if (out_bytes) {
1765         *out_bytes = 0;
1766     }
1767 }
1768 
1769 int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,
1770                           unsigned int out_bytes)
1771 {
1772     unsigned int in_total, out_total;
1773 
1774     virtqueue_get_avail_bytes(vq, &in_total, &out_total, in_bytes, out_bytes);
1775     return in_bytes <= in_total && out_bytes <= out_total;
1776 }
1777 
1778 static bool virtqueue_map_desc(VirtIODevice *vdev, unsigned int *p_num_sg,
1779                                hwaddr *addr, struct iovec *iov,
1780                                unsigned int max_num_sg, bool is_write,
1781                                hwaddr pa, size_t sz)
1782 {
1783     bool ok = false;
1784     unsigned num_sg = *p_num_sg;
1785     assert(num_sg <= max_num_sg);
1786 
1787     if (!sz) {
1788         virtio_error(vdev, "virtio: zero sized buffers are not allowed");
1789         goto out;
1790     }
1791 
1792     while (sz) {
1793         hwaddr len = sz;
1794 
1795         if (num_sg == max_num_sg) {
1796             virtio_error(vdev, "virtio: too many write descriptors in "
1797                                "indirect table");
1798             goto out;
1799         }
1800 
1801         iov[num_sg].iov_base = dma_memory_map(vdev->dma_as, pa, &len,
1802                                               is_write ?
1803                                               DMA_DIRECTION_FROM_DEVICE :
1804                                               DMA_DIRECTION_TO_DEVICE,
1805                                               MEMTXATTRS_UNSPECIFIED);
1806         if (!iov[num_sg].iov_base) {
1807             virtio_error(vdev, "virtio: bogus descriptor or out of resources");
1808             goto out;
1809         }
1810 
1811         iov[num_sg].iov_len = len;
1812         addr[num_sg] = pa;
1813 
1814         sz -= len;
1815         pa += len;
1816         num_sg++;
1817     }
1818     ok = true;
1819 
1820 out:
1821     *p_num_sg = num_sg;
1822     return ok;
1823 }
1824 
1825 /* Only used by error code paths before we have a VirtQueueElement (therefore
1826  * virtqueue_unmap_sg() can't be used).  Assumes buffers weren't written to
1827  * yet.
1828  */
1829 static void virtqueue_undo_map_desc(unsigned int out_num, unsigned int in_num,
1830                                     struct iovec *iov)
1831 {
1832     unsigned int i;
1833 
1834     for (i = 0; i < out_num + in_num; i++) {
1835         int is_write = i >= out_num;
1836 
1837         cpu_physical_memory_unmap(iov->iov_base, iov->iov_len, is_write, 0);
1838         iov++;
1839     }
1840 }
1841 
1842 static void virtqueue_map_iovec(VirtIODevice *vdev, struct iovec *sg,
1843                                 hwaddr *addr, unsigned int num_sg,
1844                                 bool is_write)
1845 {
1846     unsigned int i;
1847     hwaddr len;
1848 
1849     for (i = 0; i < num_sg; i++) {
1850         len = sg[i].iov_len;
1851         sg[i].iov_base = dma_memory_map(vdev->dma_as,
1852                                         addr[i], &len, is_write ?
1853                                         DMA_DIRECTION_FROM_DEVICE :
1854                                         DMA_DIRECTION_TO_DEVICE,
1855                                         MEMTXATTRS_UNSPECIFIED);
1856         if (!sg[i].iov_base) {
1857             error_report("virtio: error trying to map MMIO memory");
1858             exit(1);
1859         }
1860         if (len != sg[i].iov_len) {
1861             error_report("virtio: unexpected memory split");
1862             exit(1);
1863         }
1864     }
1865 }
1866 
1867 void virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem)
1868 {
1869     virtqueue_map_iovec(vdev, elem->in_sg, elem->in_addr, elem->in_num, true);
1870     virtqueue_map_iovec(vdev, elem->out_sg, elem->out_addr, elem->out_num,
1871                                                                         false);
1872 }
1873 
1874 static void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_num)
1875 {
1876     VirtQueueElement *elem;
1877     size_t in_addr_ofs = QEMU_ALIGN_UP(sz, __alignof__(elem->in_addr[0]));
1878     size_t out_addr_ofs = in_addr_ofs + in_num * sizeof(elem->in_addr[0]);
1879     size_t out_addr_end = out_addr_ofs + out_num * sizeof(elem->out_addr[0]);
1880     size_t in_sg_ofs = QEMU_ALIGN_UP(out_addr_end, __alignof__(elem->in_sg[0]));
1881     size_t out_sg_ofs = in_sg_ofs + in_num * sizeof(elem->in_sg[0]);
1882     size_t out_sg_end = out_sg_ofs + out_num * sizeof(elem->out_sg[0]);
1883 
1884     assert(sz >= sizeof(VirtQueueElement));
1885     elem = g_malloc(out_sg_end);
1886     trace_virtqueue_alloc_element(elem, sz, in_num, out_num);
1887     elem->out_num = out_num;
1888     elem->in_num = in_num;
1889     elem->in_addr = (void *)elem + in_addr_ofs;
1890     elem->out_addr = (void *)elem + out_addr_ofs;
1891     elem->in_sg = (void *)elem + in_sg_ofs;
1892     elem->out_sg = (void *)elem + out_sg_ofs;
1893     return elem;
1894 }
1895 
1896 static void *virtqueue_split_pop(VirtQueue *vq, size_t sz)
1897 {
1898     unsigned int i, head, max;
1899     VRingMemoryRegionCaches *caches;
1900     MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
1901     MemoryRegionCache *desc_cache;
1902     int64_t len;
1903     VirtIODevice *vdev = vq->vdev;
1904     VirtQueueElement *elem = NULL;
1905     unsigned out_num, in_num, elem_entries;
1906     hwaddr addr[VIRTQUEUE_MAX_SIZE];
1907     struct iovec iov[VIRTQUEUE_MAX_SIZE];
1908     VRingDesc desc;
1909     int rc;
1910 
1911     RCU_READ_LOCK_GUARD();
1912     if (virtio_queue_empty_rcu(vq)) {
1913         goto done;
1914     }
1915     /* Needed after virtio_queue_empty(), see comment in
1916      * virtqueue_num_heads(). */
1917     smp_rmb();
1918 
1919     /* When we start there are none of either input nor output. */
1920     out_num = in_num = elem_entries = 0;
1921 
1922     max = vq->vring.num;
1923 
1924     if (vq->inuse >= vq->vring.num) {
1925         virtio_error(vdev, "Virtqueue size exceeded");
1926         goto done;
1927     }
1928 
1929     if (!virtqueue_get_head(vq, vq->last_avail_idx++, &head)) {
1930         goto done;
1931     }
1932 
1933     if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
1934         vring_set_avail_event(vq, vq->last_avail_idx);
1935     }
1936 
1937     i = head;
1938 
1939     caches = vring_get_region_caches(vq);
1940     if (!caches) {
1941         virtio_error(vdev, "Region caches not initialized");
1942         goto done;
1943     }
1944 
1945     if (caches->desc.len < max * sizeof(VRingDesc)) {
1946         virtio_error(vdev, "Cannot map descriptor ring");
1947         goto done;
1948     }
1949 
1950     desc_cache = &caches->desc;
1951     vring_split_desc_read(vdev, &desc, desc_cache, i);
1952     if (desc.flags & VRING_DESC_F_INDIRECT) {
1953         if (!desc.len || (desc.len % sizeof(VRingDesc))) {
1954             virtio_error(vdev, "Invalid size for indirect buffer table");
1955             goto done;
1956         }
1957 
1958         /* loop over the indirect descriptor table */
1959         len = address_space_cache_init(&indirect_desc_cache, vdev->dma_as,
1960                                        desc.addr, desc.len, false);
1961         desc_cache = &indirect_desc_cache;
1962         if (len < desc.len) {
1963             virtio_error(vdev, "Cannot map indirect buffer");
1964             goto done;
1965         }
1966 
1967         max = desc.len / sizeof(VRingDesc);
1968         i = 0;
1969         vring_split_desc_read(vdev, &desc, desc_cache, i);
1970     }
1971 
1972     /* Collect all the descriptors */
1973     do {
1974         bool map_ok;
1975 
1976         if (desc.flags & VRING_DESC_F_WRITE) {
1977             map_ok = virtqueue_map_desc(vdev, &in_num, addr + out_num,
1978                                         iov + out_num,
1979                                         VIRTQUEUE_MAX_SIZE - out_num, true,
1980                                         desc.addr, desc.len);
1981         } else {
1982             if (in_num) {
1983                 virtio_error(vdev, "Incorrect order for descriptors");
1984                 goto err_undo_map;
1985             }
1986             map_ok = virtqueue_map_desc(vdev, &out_num, addr, iov,
1987                                         VIRTQUEUE_MAX_SIZE, false,
1988                                         desc.addr, desc.len);
1989         }
1990         if (!map_ok) {
1991             goto err_undo_map;
1992         }
1993 
1994         /* If we've got too many, that implies a descriptor loop. */
1995         if (++elem_entries > max) {
1996             virtio_error(vdev, "Looped descriptor");
1997             goto err_undo_map;
1998         }
1999 
2000         rc = virtqueue_split_read_next_desc(vdev, &desc, desc_cache, max, &i);
2001     } while (rc == VIRTQUEUE_READ_DESC_MORE);
2002 
2003     if (rc == VIRTQUEUE_READ_DESC_ERROR) {
2004         goto err_undo_map;
2005     }
2006 
2007     /* Now copy what we have collected and mapped */
2008     elem = virtqueue_alloc_element(sz, out_num, in_num);
2009     elem->index = head;
2010     elem->ndescs = 1;
2011     for (i = 0; i < out_num; i++) {
2012         elem->out_addr[i] = addr[i];
2013         elem->out_sg[i] = iov[i];
2014     }
2015     for (i = 0; i < in_num; i++) {
2016         elem->in_addr[i] = addr[out_num + i];
2017         elem->in_sg[i] = iov[out_num + i];
2018     }
2019 
2020     vq->inuse++;
2021 
2022     trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);
2023 done:
2024     address_space_cache_destroy(&indirect_desc_cache);
2025 
2026     return elem;
2027 
2028 err_undo_map:
2029     virtqueue_undo_map_desc(out_num, in_num, iov);
2030     goto done;
2031 }
2032 
2033 static void *virtqueue_packed_pop(VirtQueue *vq, size_t sz)
2034 {
2035     unsigned int i, max;
2036     VRingMemoryRegionCaches *caches;
2037     MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
2038     MemoryRegionCache *desc_cache;
2039     int64_t len;
2040     VirtIODevice *vdev = vq->vdev;
2041     VirtQueueElement *elem = NULL;
2042     unsigned out_num, in_num, elem_entries;
2043     hwaddr addr[VIRTQUEUE_MAX_SIZE];
2044     struct iovec iov[VIRTQUEUE_MAX_SIZE];
2045     VRingPackedDesc desc;
2046     uint16_t id;
2047     int rc;
2048 
2049     RCU_READ_LOCK_GUARD();
2050     if (virtio_queue_packed_empty_rcu(vq)) {
2051         goto done;
2052     }
2053 
2054     /* When we start there are none of either input nor output. */
2055     out_num = in_num = elem_entries = 0;
2056 
2057     max = vq->vring.num;
2058 
2059     if (vq->inuse >= vq->vring.num) {
2060         virtio_error(vdev, "Virtqueue size exceeded");
2061         goto done;
2062     }
2063 
2064     i = vq->last_avail_idx;
2065 
2066     caches = vring_get_region_caches(vq);
2067     if (!caches) {
2068         virtio_error(vdev, "Region caches not initialized");
2069         goto done;
2070     }
2071 
2072     if (caches->desc.len < max * sizeof(VRingDesc)) {
2073         virtio_error(vdev, "Cannot map descriptor ring");
2074         goto done;
2075     }
2076 
2077     desc_cache = &caches->desc;
2078     vring_packed_desc_read(vdev, &desc, desc_cache, i, true);
2079     id = desc.id;
2080     if (desc.flags & VRING_DESC_F_INDIRECT) {
2081         if (desc.len % sizeof(VRingPackedDesc)) {
2082             virtio_error(vdev, "Invalid size for indirect buffer table");
2083             goto done;
2084         }
2085 
2086         /* loop over the indirect descriptor table */
2087         len = address_space_cache_init(&indirect_desc_cache, vdev->dma_as,
2088                                        desc.addr, desc.len, false);
2089         desc_cache = &indirect_desc_cache;
2090         if (len < desc.len) {
2091             virtio_error(vdev, "Cannot map indirect buffer");
2092             goto done;
2093         }
2094 
2095         max = desc.len / sizeof(VRingPackedDesc);
2096         i = 0;
2097         vring_packed_desc_read(vdev, &desc, desc_cache, i, false);
2098     }
2099 
2100     /* Collect all the descriptors */
2101     do {
2102         bool map_ok;
2103 
2104         if (desc.flags & VRING_DESC_F_WRITE) {
2105             map_ok = virtqueue_map_desc(vdev, &in_num, addr + out_num,
2106                                         iov + out_num,
2107                                         VIRTQUEUE_MAX_SIZE - out_num, true,
2108                                         desc.addr, desc.len);
2109         } else {
2110             if (in_num) {
2111                 virtio_error(vdev, "Incorrect order for descriptors");
2112                 goto err_undo_map;
2113             }
2114             map_ok = virtqueue_map_desc(vdev, &out_num, addr, iov,
2115                                         VIRTQUEUE_MAX_SIZE, false,
2116                                         desc.addr, desc.len);
2117         }
2118         if (!map_ok) {
2119             goto err_undo_map;
2120         }
2121 
2122         /* If we've got too many, that implies a descriptor loop. */
2123         if (++elem_entries > max) {
2124             virtio_error(vdev, "Looped descriptor");
2125             goto err_undo_map;
2126         }
2127 
2128         rc = virtqueue_packed_read_next_desc(vq, &desc, desc_cache, max, &i,
2129                                              desc_cache ==
2130                                              &indirect_desc_cache);
2131     } while (rc == VIRTQUEUE_READ_DESC_MORE);
2132 
2133     /* Now copy what we have collected and mapped */
2134     elem = virtqueue_alloc_element(sz, out_num, in_num);
2135     for (i = 0; i < out_num; i++) {
2136         elem->out_addr[i] = addr[i];
2137         elem->out_sg[i] = iov[i];
2138     }
2139     for (i = 0; i < in_num; i++) {
2140         elem->in_addr[i] = addr[out_num + i];
2141         elem->in_sg[i] = iov[out_num + i];
2142     }
2143 
2144     elem->index = id;
2145     elem->ndescs = (desc_cache == &indirect_desc_cache) ? 1 : elem_entries;
2146     vq->last_avail_idx += elem->ndescs;
2147     vq->inuse += elem->ndescs;
2148 
2149     if (vq->last_avail_idx >= vq->vring.num) {
2150         vq->last_avail_idx -= vq->vring.num;
2151         vq->last_avail_wrap_counter ^= 1;
2152     }
2153 
2154     vq->shadow_avail_idx = vq->last_avail_idx;
2155     vq->shadow_avail_wrap_counter = vq->last_avail_wrap_counter;
2156 
2157     trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);
2158 done:
2159     address_space_cache_destroy(&indirect_desc_cache);
2160 
2161     return elem;
2162 
2163 err_undo_map:
2164     virtqueue_undo_map_desc(out_num, in_num, iov);
2165     goto done;
2166 }
2167 
2168 void *virtqueue_pop(VirtQueue *vq, size_t sz)
2169 {
2170     if (virtio_device_disabled(vq->vdev)) {
2171         return NULL;
2172     }
2173 
2174     if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
2175         return virtqueue_packed_pop(vq, sz);
2176     } else {
2177         return virtqueue_split_pop(vq, sz);
2178     }
2179 }
2180 
2181 static unsigned int virtqueue_packed_drop_all(VirtQueue *vq)
2182 {
2183     VRingMemoryRegionCaches *caches;
2184     MemoryRegionCache *desc_cache;
2185     unsigned int dropped = 0;
2186     VirtQueueElement elem = {};
2187     VirtIODevice *vdev = vq->vdev;
2188     VRingPackedDesc desc;
2189 
2190     RCU_READ_LOCK_GUARD();
2191 
2192     caches = vring_get_region_caches(vq);
2193     if (!caches) {
2194         return 0;
2195     }
2196 
2197     desc_cache = &caches->desc;
2198 
2199     virtio_queue_set_notification(vq, 0);
2200 
2201     while (vq->inuse < vq->vring.num) {
2202         unsigned int idx = vq->last_avail_idx;
2203         /*
2204          * works similar to virtqueue_pop but does not map buffers
2205          * and does not allocate any memory.
2206          */
2207         vring_packed_desc_read(vdev, &desc, desc_cache,
2208                                vq->last_avail_idx , true);
2209         if (!is_desc_avail(desc.flags, vq->last_avail_wrap_counter)) {
2210             break;
2211         }
2212         elem.index = desc.id;
2213         elem.ndescs = 1;
2214         while (virtqueue_packed_read_next_desc(vq, &desc, desc_cache,
2215                                                vq->vring.num, &idx, false)) {
2216             ++elem.ndescs;
2217         }
2218         /*
2219          * immediately push the element, nothing to unmap
2220          * as both in_num and out_num are set to 0.
2221          */
2222         virtqueue_push(vq, &elem, 0);
2223         dropped++;
2224         vq->last_avail_idx += elem.ndescs;
2225         if (vq->last_avail_idx >= vq->vring.num) {
2226             vq->last_avail_idx -= vq->vring.num;
2227             vq->last_avail_wrap_counter ^= 1;
2228         }
2229     }
2230 
2231     return dropped;
2232 }
2233 
2234 static unsigned int virtqueue_split_drop_all(VirtQueue *vq)
2235 {
2236     unsigned int dropped = 0;
2237     VirtQueueElement elem = {};
2238     VirtIODevice *vdev = vq->vdev;
2239     bool fEventIdx = virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
2240 
2241     while (!virtio_queue_empty(vq) && vq->inuse < vq->vring.num) {
2242         /* works similar to virtqueue_pop but does not map buffers
2243         * and does not allocate any memory */
2244         smp_rmb();
2245         if (!virtqueue_get_head(vq, vq->last_avail_idx, &elem.index)) {
2246             break;
2247         }
2248         vq->inuse++;
2249         vq->last_avail_idx++;
2250         if (fEventIdx) {
2251             vring_set_avail_event(vq, vq->last_avail_idx);
2252         }
2253         /* immediately push the element, nothing to unmap
2254          * as both in_num and out_num are set to 0 */
2255         virtqueue_push(vq, &elem, 0);
2256         dropped++;
2257     }
2258 
2259     return dropped;
2260 }
2261 
2262 /* virtqueue_drop_all:
2263  * @vq: The #VirtQueue
2264  * Drops all queued buffers and indicates them to the guest
2265  * as if they are done. Useful when buffers can not be
2266  * processed but must be returned to the guest.
2267  */
2268 unsigned int virtqueue_drop_all(VirtQueue *vq)
2269 {
2270     struct VirtIODevice *vdev = vq->vdev;
2271 
2272     if (virtio_device_disabled(vq->vdev)) {
2273         return 0;
2274     }
2275 
2276     if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
2277         return virtqueue_packed_drop_all(vq);
2278     } else {
2279         return virtqueue_split_drop_all(vq);
2280     }
2281 }
2282 
2283 /* Reading and writing a structure directly to QEMUFile is *awful*, but
2284  * it is what QEMU has always done by mistake.  We can change it sooner
2285  * or later by bumping the version number of the affected vm states.
2286  * In the meanwhile, since the in-memory layout of VirtQueueElement
2287  * has changed, we need to marshal to and from the layout that was
2288  * used before the change.
2289  */
2290 typedef struct VirtQueueElementOld {
2291     unsigned int index;
2292     unsigned int out_num;
2293     unsigned int in_num;
2294     hwaddr in_addr[VIRTQUEUE_MAX_SIZE];
2295     hwaddr out_addr[VIRTQUEUE_MAX_SIZE];
2296     struct iovec in_sg[VIRTQUEUE_MAX_SIZE];
2297     struct iovec out_sg[VIRTQUEUE_MAX_SIZE];
2298 } VirtQueueElementOld;
2299 
2300 void *qemu_get_virtqueue_element(VirtIODevice *vdev, QEMUFile *f, size_t sz)
2301 {
2302     VirtQueueElement *elem;
2303     VirtQueueElementOld data;
2304     int i;
2305 
2306     qemu_get_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld));
2307 
2308     /* TODO: teach all callers that this can fail, and return failure instead
2309      * of asserting here.
2310      * This is just one thing (there are probably more) that must be
2311      * fixed before we can allow NDEBUG compilation.
2312      */
2313     assert(ARRAY_SIZE(data.in_addr) >= data.in_num);
2314     assert(ARRAY_SIZE(data.out_addr) >= data.out_num);
2315 
2316     elem = virtqueue_alloc_element(sz, data.out_num, data.in_num);
2317     elem->index = data.index;
2318 
2319     for (i = 0; i < elem->in_num; i++) {
2320         elem->in_addr[i] = data.in_addr[i];
2321     }
2322 
2323     for (i = 0; i < elem->out_num; i++) {
2324         elem->out_addr[i] = data.out_addr[i];
2325     }
2326 
2327     for (i = 0; i < elem->in_num; i++) {
2328         /* Base is overwritten by virtqueue_map.  */
2329         elem->in_sg[i].iov_base = 0;
2330         elem->in_sg[i].iov_len = data.in_sg[i].iov_len;
2331     }
2332 
2333     for (i = 0; i < elem->out_num; i++) {
2334         /* Base is overwritten by virtqueue_map.  */
2335         elem->out_sg[i].iov_base = 0;
2336         elem->out_sg[i].iov_len = data.out_sg[i].iov_len;
2337     }
2338 
2339     if (virtio_host_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
2340         qemu_get_be32s(f, &elem->ndescs);
2341     }
2342 
2343     virtqueue_map(vdev, elem);
2344     return elem;
2345 }
2346 
2347 void qemu_put_virtqueue_element(VirtIODevice *vdev, QEMUFile *f,
2348                                 VirtQueueElement *elem)
2349 {
2350     VirtQueueElementOld data;
2351     int i;
2352 
2353     memset(&data, 0, sizeof(data));
2354     data.index = elem->index;
2355     data.in_num = elem->in_num;
2356     data.out_num = elem->out_num;
2357 
2358     for (i = 0; i < elem->in_num; i++) {
2359         data.in_addr[i] = elem->in_addr[i];
2360     }
2361 
2362     for (i = 0; i < elem->out_num; i++) {
2363         data.out_addr[i] = elem->out_addr[i];
2364     }
2365 
2366     for (i = 0; i < elem->in_num; i++) {
2367         /* Base is overwritten by virtqueue_map when loading.  Do not
2368          * save it, as it would leak the QEMU address space layout.  */
2369         data.in_sg[i].iov_len = elem->in_sg[i].iov_len;
2370     }
2371 
2372     for (i = 0; i < elem->out_num; i++) {
2373         /* Do not save iov_base as above.  */
2374         data.out_sg[i].iov_len = elem->out_sg[i].iov_len;
2375     }
2376 
2377     if (virtio_host_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
2378         qemu_put_be32s(f, &elem->ndescs);
2379     }
2380 
2381     qemu_put_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld));
2382 }
2383 
2384 /* virtio device */
2385 static void virtio_notify_vector(VirtIODevice *vdev, uint16_t vector)
2386 {
2387     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2388     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2389 
2390     if (virtio_device_disabled(vdev)) {
2391         return;
2392     }
2393 
2394     if (k->notify) {
2395         k->notify(qbus->parent, vector);
2396     }
2397 }
2398 
2399 void virtio_update_irq(VirtIODevice *vdev)
2400 {
2401     virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
2402 }
2403 
2404 static int virtio_validate_features(VirtIODevice *vdev)
2405 {
2406     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2407 
2408     if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM) &&
2409         !virtio_vdev_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM)) {
2410         return -EFAULT;
2411     }
2412 
2413     if (k->validate_features) {
2414         return k->validate_features(vdev);
2415     } else {
2416         return 0;
2417     }
2418 }
2419 
2420 int virtio_set_status(VirtIODevice *vdev, uint8_t val)
2421 {
2422     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2423     trace_virtio_set_status(vdev, val);
2424 
2425     if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
2426         if (!(vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) &&
2427             val & VIRTIO_CONFIG_S_FEATURES_OK) {
2428             int ret = virtio_validate_features(vdev);
2429 
2430             if (ret) {
2431                 return ret;
2432             }
2433         }
2434     }
2435 
2436     if ((vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) !=
2437         (val & VIRTIO_CONFIG_S_DRIVER_OK)) {
2438         virtio_set_started(vdev, val & VIRTIO_CONFIG_S_DRIVER_OK);
2439     }
2440 
2441     if (k->set_status) {
2442         k->set_status(vdev, val);
2443     }
2444     vdev->status = val;
2445 
2446     return 0;
2447 }
2448 
2449 static enum virtio_device_endian virtio_default_endian(void)
2450 {
2451     if (target_words_bigendian()) {
2452         return VIRTIO_DEVICE_ENDIAN_BIG;
2453     } else {
2454         return VIRTIO_DEVICE_ENDIAN_LITTLE;
2455     }
2456 }
2457 
2458 static enum virtio_device_endian virtio_current_cpu_endian(void)
2459 {
2460     if (cpu_virtio_is_big_endian(current_cpu)) {
2461         return VIRTIO_DEVICE_ENDIAN_BIG;
2462     } else {
2463         return VIRTIO_DEVICE_ENDIAN_LITTLE;
2464     }
2465 }
2466 
2467 static void __virtio_queue_reset(VirtIODevice *vdev, uint32_t i)
2468 {
2469     vdev->vq[i].vring.desc = 0;
2470     vdev->vq[i].vring.avail = 0;
2471     vdev->vq[i].vring.used = 0;
2472     vdev->vq[i].last_avail_idx = 0;
2473     vdev->vq[i].shadow_avail_idx = 0;
2474     vdev->vq[i].used_idx = 0;
2475     vdev->vq[i].last_avail_wrap_counter = true;
2476     vdev->vq[i].shadow_avail_wrap_counter = true;
2477     vdev->vq[i].used_wrap_counter = true;
2478     virtio_queue_set_vector(vdev, i, VIRTIO_NO_VECTOR);
2479     vdev->vq[i].signalled_used = 0;
2480     vdev->vq[i].signalled_used_valid = false;
2481     vdev->vq[i].notification = true;
2482     vdev->vq[i].vring.num = vdev->vq[i].vring.num_default;
2483     vdev->vq[i].inuse = 0;
2484     virtio_virtqueue_reset_region_cache(&vdev->vq[i]);
2485 }
2486 
2487 void virtio_reset(void *opaque)
2488 {
2489     VirtIODevice *vdev = opaque;
2490     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2491     int i;
2492 
2493     virtio_set_status(vdev, 0);
2494     if (current_cpu) {
2495         /* Guest initiated reset */
2496         vdev->device_endian = virtio_current_cpu_endian();
2497     } else {
2498         /* System reset */
2499         vdev->device_endian = virtio_default_endian();
2500     }
2501 
2502     if (k->reset) {
2503         k->reset(vdev);
2504     }
2505 
2506     vdev->start_on_kick = false;
2507     vdev->started = false;
2508     vdev->broken = false;
2509     vdev->guest_features = 0;
2510     vdev->queue_sel = 0;
2511     vdev->status = 0;
2512     vdev->disabled = false;
2513     qatomic_set(&vdev->isr, 0);
2514     vdev->config_vector = VIRTIO_NO_VECTOR;
2515     virtio_notify_vector(vdev, vdev->config_vector);
2516 
2517     for(i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2518         __virtio_queue_reset(vdev, i);
2519     }
2520 }
2521 
2522 uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr)
2523 {
2524     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2525     uint8_t val;
2526 
2527     if (addr + sizeof(val) > vdev->config_len) {
2528         return (uint32_t)-1;
2529     }
2530 
2531     k->get_config(vdev, vdev->config);
2532 
2533     val = ldub_p(vdev->config + addr);
2534     return val;
2535 }
2536 
2537 uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr)
2538 {
2539     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2540     uint16_t val;
2541 
2542     if (addr + sizeof(val) > vdev->config_len) {
2543         return (uint32_t)-1;
2544     }
2545 
2546     k->get_config(vdev, vdev->config);
2547 
2548     val = lduw_p(vdev->config + addr);
2549     return val;
2550 }
2551 
2552 uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr)
2553 {
2554     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2555     uint32_t val;
2556 
2557     if (addr + sizeof(val) > vdev->config_len) {
2558         return (uint32_t)-1;
2559     }
2560 
2561     k->get_config(vdev, vdev->config);
2562 
2563     val = ldl_p(vdev->config + addr);
2564     return val;
2565 }
2566 
2567 void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data)
2568 {
2569     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2570     uint8_t val = data;
2571 
2572     if (addr + sizeof(val) > vdev->config_len) {
2573         return;
2574     }
2575 
2576     stb_p(vdev->config + addr, val);
2577 
2578     if (k->set_config) {
2579         k->set_config(vdev, vdev->config);
2580     }
2581 }
2582 
2583 void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data)
2584 {
2585     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2586     uint16_t val = data;
2587 
2588     if (addr + sizeof(val) > vdev->config_len) {
2589         return;
2590     }
2591 
2592     stw_p(vdev->config + addr, val);
2593 
2594     if (k->set_config) {
2595         k->set_config(vdev, vdev->config);
2596     }
2597 }
2598 
2599 void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data)
2600 {
2601     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2602     uint32_t val = data;
2603 
2604     if (addr + sizeof(val) > vdev->config_len) {
2605         return;
2606     }
2607 
2608     stl_p(vdev->config + addr, val);
2609 
2610     if (k->set_config) {
2611         k->set_config(vdev, vdev->config);
2612     }
2613 }
2614 
2615 uint32_t virtio_config_modern_readb(VirtIODevice *vdev, uint32_t addr)
2616 {
2617     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2618     uint8_t val;
2619 
2620     if (addr + sizeof(val) > vdev->config_len) {
2621         return (uint32_t)-1;
2622     }
2623 
2624     k->get_config(vdev, vdev->config);
2625 
2626     val = ldub_p(vdev->config + addr);
2627     return val;
2628 }
2629 
2630 uint32_t virtio_config_modern_readw(VirtIODevice *vdev, uint32_t addr)
2631 {
2632     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2633     uint16_t val;
2634 
2635     if (addr + sizeof(val) > vdev->config_len) {
2636         return (uint32_t)-1;
2637     }
2638 
2639     k->get_config(vdev, vdev->config);
2640 
2641     val = lduw_le_p(vdev->config + addr);
2642     return val;
2643 }
2644 
2645 uint32_t virtio_config_modern_readl(VirtIODevice *vdev, uint32_t addr)
2646 {
2647     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2648     uint32_t val;
2649 
2650     if (addr + sizeof(val) > vdev->config_len) {
2651         return (uint32_t)-1;
2652     }
2653 
2654     k->get_config(vdev, vdev->config);
2655 
2656     val = ldl_le_p(vdev->config + addr);
2657     return val;
2658 }
2659 
2660 void virtio_config_modern_writeb(VirtIODevice *vdev,
2661                                  uint32_t addr, uint32_t data)
2662 {
2663     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2664     uint8_t val = data;
2665 
2666     if (addr + sizeof(val) > vdev->config_len) {
2667         return;
2668     }
2669 
2670     stb_p(vdev->config + addr, val);
2671 
2672     if (k->set_config) {
2673         k->set_config(vdev, vdev->config);
2674     }
2675 }
2676 
2677 void virtio_config_modern_writew(VirtIODevice *vdev,
2678                                  uint32_t addr, uint32_t data)
2679 {
2680     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2681     uint16_t val = data;
2682 
2683     if (addr + sizeof(val) > vdev->config_len) {
2684         return;
2685     }
2686 
2687     stw_le_p(vdev->config + addr, val);
2688 
2689     if (k->set_config) {
2690         k->set_config(vdev, vdev->config);
2691     }
2692 }
2693 
2694 void virtio_config_modern_writel(VirtIODevice *vdev,
2695                                  uint32_t addr, uint32_t data)
2696 {
2697     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2698     uint32_t val = data;
2699 
2700     if (addr + sizeof(val) > vdev->config_len) {
2701         return;
2702     }
2703 
2704     stl_le_p(vdev->config + addr, val);
2705 
2706     if (k->set_config) {
2707         k->set_config(vdev, vdev->config);
2708     }
2709 }
2710 
2711 void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr)
2712 {
2713     if (!vdev->vq[n].vring.num) {
2714         return;
2715     }
2716     vdev->vq[n].vring.desc = addr;
2717     virtio_queue_update_rings(vdev, n);
2718 }
2719 
2720 hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n)
2721 {
2722     return vdev->vq[n].vring.desc;
2723 }
2724 
2725 void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc,
2726                             hwaddr avail, hwaddr used)
2727 {
2728     if (!vdev->vq[n].vring.num) {
2729         return;
2730     }
2731     vdev->vq[n].vring.desc = desc;
2732     vdev->vq[n].vring.avail = avail;
2733     vdev->vq[n].vring.used = used;
2734     virtio_init_region_cache(vdev, n);
2735 }
2736 
2737 void virtio_queue_set_num(VirtIODevice *vdev, int n, int num)
2738 {
2739     /* Don't allow guest to flip queue between existent and
2740      * nonexistent states, or to set it to an invalid size.
2741      */
2742     if (!!num != !!vdev->vq[n].vring.num ||
2743         num > VIRTQUEUE_MAX_SIZE ||
2744         num < 0) {
2745         return;
2746     }
2747     vdev->vq[n].vring.num = num;
2748 }
2749 
2750 VirtQueue *virtio_vector_first_queue(VirtIODevice *vdev, uint16_t vector)
2751 {
2752     return QLIST_FIRST(&vdev->vector_queues[vector]);
2753 }
2754 
2755 VirtQueue *virtio_vector_next_queue(VirtQueue *vq)
2756 {
2757     return QLIST_NEXT(vq, node);
2758 }
2759 
2760 int virtio_queue_get_num(VirtIODevice *vdev, int n)
2761 {
2762     return vdev->vq[n].vring.num;
2763 }
2764 
2765 int virtio_queue_get_max_num(VirtIODevice *vdev, int n)
2766 {
2767     return vdev->vq[n].vring.num_default;
2768 }
2769 
2770 int virtio_get_num_queues(VirtIODevice *vdev)
2771 {
2772     int i;
2773 
2774     for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2775         if (!virtio_queue_get_num(vdev, i)) {
2776             break;
2777         }
2778     }
2779 
2780     return i;
2781 }
2782 
2783 void virtio_queue_set_align(VirtIODevice *vdev, int n, int align)
2784 {
2785     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2786     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2787 
2788     /* virtio-1 compliant devices cannot change the alignment */
2789     if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
2790         error_report("tried to modify queue alignment for virtio-1 device");
2791         return;
2792     }
2793     /* Check that the transport told us it was going to do this
2794      * (so a buggy transport will immediately assert rather than
2795      * silently failing to migrate this state)
2796      */
2797     assert(k->has_variable_vring_alignment);
2798 
2799     if (align) {
2800         vdev->vq[n].vring.align = align;
2801         virtio_queue_update_rings(vdev, n);
2802     }
2803 }
2804 
2805 static void virtio_queue_notify_vq(VirtQueue *vq)
2806 {
2807     if (vq->vring.desc && vq->handle_output) {
2808         VirtIODevice *vdev = vq->vdev;
2809 
2810         if (unlikely(vdev->broken)) {
2811             return;
2812         }
2813 
2814         trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
2815         vq->handle_output(vdev, vq);
2816 
2817         if (unlikely(vdev->start_on_kick)) {
2818             virtio_set_started(vdev, true);
2819         }
2820     }
2821 }
2822 
2823 void virtio_queue_notify(VirtIODevice *vdev, int n)
2824 {
2825     VirtQueue *vq = &vdev->vq[n];
2826 
2827     if (unlikely(!vq->vring.desc || vdev->broken)) {
2828         return;
2829     }
2830 
2831     trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
2832     if (vq->host_notifier_enabled) {
2833         event_notifier_set(&vq->host_notifier);
2834     } else if (vq->handle_output) {
2835         vq->handle_output(vdev, vq);
2836 
2837         if (unlikely(vdev->start_on_kick)) {
2838             virtio_set_started(vdev, true);
2839         }
2840     }
2841 }
2842 
2843 uint16_t virtio_queue_vector(VirtIODevice *vdev, int n)
2844 {
2845     return n < VIRTIO_QUEUE_MAX ? vdev->vq[n].vector :
2846         VIRTIO_NO_VECTOR;
2847 }
2848 
2849 void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector)
2850 {
2851     VirtQueue *vq = &vdev->vq[n];
2852 
2853     if (n < VIRTIO_QUEUE_MAX) {
2854         if (vdev->vector_queues &&
2855             vdev->vq[n].vector != VIRTIO_NO_VECTOR) {
2856             QLIST_REMOVE(vq, node);
2857         }
2858         vdev->vq[n].vector = vector;
2859         if (vdev->vector_queues &&
2860             vector != VIRTIO_NO_VECTOR) {
2861             QLIST_INSERT_HEAD(&vdev->vector_queues[vector], vq, node);
2862         }
2863     }
2864 }
2865 
2866 VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
2867                             VirtIOHandleOutput handle_output)
2868 {
2869     int i;
2870 
2871     for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2872         if (vdev->vq[i].vring.num == 0)
2873             break;
2874     }
2875 
2876     if (i == VIRTIO_QUEUE_MAX || queue_size > VIRTQUEUE_MAX_SIZE)
2877         abort();
2878 
2879     vdev->vq[i].vring.num = queue_size;
2880     vdev->vq[i].vring.num_default = queue_size;
2881     vdev->vq[i].vring.align = VIRTIO_PCI_VRING_ALIGN;
2882     vdev->vq[i].handle_output = handle_output;
2883     vdev->vq[i].used_elems = g_new0(VirtQueueElement, queue_size);
2884 
2885     return &vdev->vq[i];
2886 }
2887 
2888 void virtio_delete_queue(VirtQueue *vq)
2889 {
2890     vq->vring.num = 0;
2891     vq->vring.num_default = 0;
2892     vq->handle_output = NULL;
2893     g_free(vq->used_elems);
2894     vq->used_elems = NULL;
2895     virtio_virtqueue_reset_region_cache(vq);
2896 }
2897 
2898 void virtio_del_queue(VirtIODevice *vdev, int n)
2899 {
2900     if (n < 0 || n >= VIRTIO_QUEUE_MAX) {
2901         abort();
2902     }
2903 
2904     virtio_delete_queue(&vdev->vq[n]);
2905 }
2906 
2907 static void virtio_set_isr(VirtIODevice *vdev, int value)
2908 {
2909     uint8_t old = qatomic_read(&vdev->isr);
2910 
2911     /* Do not write ISR if it does not change, so that its cacheline remains
2912      * shared in the common case where the guest does not read it.
2913      */
2914     if ((old & value) != value) {
2915         qatomic_or(&vdev->isr, value);
2916     }
2917 }
2918 
2919 /* Called within rcu_read_lock(). */
2920 static bool virtio_split_should_notify(VirtIODevice *vdev, VirtQueue *vq)
2921 {
2922     uint16_t old, new;
2923     bool v;
2924     /* We need to expose used array entries before checking used event. */
2925     smp_mb();
2926     /* Always notify when queue is empty (when feature acknowledge) */
2927     if (virtio_vdev_has_feature(vdev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
2928         !vq->inuse && virtio_queue_empty(vq)) {
2929         return true;
2930     }
2931 
2932     if (!virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
2933         return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT);
2934     }
2935 
2936     v = vq->signalled_used_valid;
2937     vq->signalled_used_valid = true;
2938     old = vq->signalled_used;
2939     new = vq->signalled_used = vq->used_idx;
2940     return !v || vring_need_event(vring_get_used_event(vq), new, old);
2941 }
2942 
2943 static bool vring_packed_need_event(VirtQueue *vq, bool wrap,
2944                                     uint16_t off_wrap, uint16_t new,
2945                                     uint16_t old)
2946 {
2947     int off = off_wrap & ~(1 << 15);
2948 
2949     if (wrap != off_wrap >> 15) {
2950         off -= vq->vring.num;
2951     }
2952 
2953     return vring_need_event(off, new, old);
2954 }
2955 
2956 /* Called within rcu_read_lock(). */
2957 static bool virtio_packed_should_notify(VirtIODevice *vdev, VirtQueue *vq)
2958 {
2959     VRingPackedDescEvent e;
2960     uint16_t old, new;
2961     bool v;
2962     VRingMemoryRegionCaches *caches;
2963 
2964     caches = vring_get_region_caches(vq);
2965     if (!caches) {
2966         return false;
2967     }
2968 
2969     vring_packed_event_read(vdev, &caches->avail, &e);
2970 
2971     old = vq->signalled_used;
2972     new = vq->signalled_used = vq->used_idx;
2973     v = vq->signalled_used_valid;
2974     vq->signalled_used_valid = true;
2975 
2976     if (e.flags == VRING_PACKED_EVENT_FLAG_DISABLE) {
2977         return false;
2978     } else if (e.flags == VRING_PACKED_EVENT_FLAG_ENABLE) {
2979         return true;
2980     }
2981 
2982     return !v || vring_packed_need_event(vq, vq->used_wrap_counter,
2983                                          e.off_wrap, new, old);
2984 }
2985 
2986 /* Called within rcu_read_lock().  */
2987 static bool virtio_should_notify(VirtIODevice *vdev, VirtQueue *vq)
2988 {
2989     if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
2990         return virtio_packed_should_notify(vdev, vq);
2991     } else {
2992         return virtio_split_should_notify(vdev, vq);
2993     }
2994 }
2995 
2996 void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq)
2997 {
2998     WITH_RCU_READ_LOCK_GUARD() {
2999         if (!virtio_should_notify(vdev, vq)) {
3000             return;
3001         }
3002     }
3003 
3004     trace_virtio_notify_irqfd(vdev, vq);
3005 
3006     /*
3007      * virtio spec 1.0 says ISR bit 0 should be ignored with MSI, but
3008      * windows drivers included in virtio-win 1.8.0 (circa 2015) are
3009      * incorrectly polling this bit during crashdump and hibernation
3010      * in MSI mode, causing a hang if this bit is never updated.
3011      * Recent releases of Windows do not really shut down, but rather
3012      * log out and hibernate to make the next startup faster.  Hence,
3013      * this manifested as a more serious hang during shutdown with
3014      *
3015      * Next driver release from 2016 fixed this problem, so working around it
3016      * is not a must, but it's easy to do so let's do it here.
3017      *
3018      * Note: it's safe to update ISR from any thread as it was switched
3019      * to an atomic operation.
3020      */
3021     virtio_set_isr(vq->vdev, 0x1);
3022     event_notifier_set(&vq->guest_notifier);
3023 }
3024 
3025 static void virtio_irq(VirtQueue *vq)
3026 {
3027     virtio_set_isr(vq->vdev, 0x1);
3028     virtio_notify_vector(vq->vdev, vq->vector);
3029 }
3030 
3031 void virtio_notify(VirtIODevice *vdev, VirtQueue *vq)
3032 {
3033     WITH_RCU_READ_LOCK_GUARD() {
3034         if (!virtio_should_notify(vdev, vq)) {
3035             return;
3036         }
3037     }
3038 
3039     trace_virtio_notify(vdev, vq);
3040     virtio_irq(vq);
3041 }
3042 
3043 void virtio_notify_config(VirtIODevice *vdev)
3044 {
3045     if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK))
3046         return;
3047 
3048     virtio_set_isr(vdev, 0x3);
3049     vdev->generation++;
3050     virtio_notify_vector(vdev, vdev->config_vector);
3051 }
3052 
3053 static bool virtio_device_endian_needed(void *opaque)
3054 {
3055     VirtIODevice *vdev = opaque;
3056 
3057     assert(vdev->device_endian != VIRTIO_DEVICE_ENDIAN_UNKNOWN);
3058     if (!virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
3059         return vdev->device_endian != virtio_default_endian();
3060     }
3061     /* Devices conforming to VIRTIO 1.0 or later are always LE. */
3062     return vdev->device_endian != VIRTIO_DEVICE_ENDIAN_LITTLE;
3063 }
3064 
3065 static bool virtio_64bit_features_needed(void *opaque)
3066 {
3067     VirtIODevice *vdev = opaque;
3068 
3069     return (vdev->host_features >> 32) != 0;
3070 }
3071 
3072 static bool virtio_virtqueue_needed(void *opaque)
3073 {
3074     VirtIODevice *vdev = opaque;
3075 
3076     return virtio_host_has_feature(vdev, VIRTIO_F_VERSION_1);
3077 }
3078 
3079 static bool virtio_packed_virtqueue_needed(void *opaque)
3080 {
3081     VirtIODevice *vdev = opaque;
3082 
3083     return virtio_host_has_feature(vdev, VIRTIO_F_RING_PACKED);
3084 }
3085 
3086 static bool virtio_ringsize_needed(void *opaque)
3087 {
3088     VirtIODevice *vdev = opaque;
3089     int i;
3090 
3091     for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
3092         if (vdev->vq[i].vring.num != vdev->vq[i].vring.num_default) {
3093             return true;
3094         }
3095     }
3096     return false;
3097 }
3098 
3099 static bool virtio_extra_state_needed(void *opaque)
3100 {
3101     VirtIODevice *vdev = opaque;
3102     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3103     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3104 
3105     return k->has_extra_state &&
3106         k->has_extra_state(qbus->parent);
3107 }
3108 
3109 static bool virtio_broken_needed(void *opaque)
3110 {
3111     VirtIODevice *vdev = opaque;
3112 
3113     return vdev->broken;
3114 }
3115 
3116 static bool virtio_started_needed(void *opaque)
3117 {
3118     VirtIODevice *vdev = opaque;
3119 
3120     return vdev->started;
3121 }
3122 
3123 static bool virtio_disabled_needed(void *opaque)
3124 {
3125     VirtIODevice *vdev = opaque;
3126 
3127     return vdev->disabled;
3128 }
3129 
3130 static const VMStateDescription vmstate_virtqueue = {
3131     .name = "virtqueue_state",
3132     .version_id = 1,
3133     .minimum_version_id = 1,
3134     .fields = (VMStateField[]) {
3135         VMSTATE_UINT64(vring.avail, struct VirtQueue),
3136         VMSTATE_UINT64(vring.used, struct VirtQueue),
3137         VMSTATE_END_OF_LIST()
3138     }
3139 };
3140 
3141 static const VMStateDescription vmstate_packed_virtqueue = {
3142     .name = "packed_virtqueue_state",
3143     .version_id = 1,
3144     .minimum_version_id = 1,
3145     .fields = (VMStateField[]) {
3146         VMSTATE_UINT16(last_avail_idx, struct VirtQueue),
3147         VMSTATE_BOOL(last_avail_wrap_counter, struct VirtQueue),
3148         VMSTATE_UINT16(used_idx, struct VirtQueue),
3149         VMSTATE_BOOL(used_wrap_counter, struct VirtQueue),
3150         VMSTATE_UINT32(inuse, struct VirtQueue),
3151         VMSTATE_END_OF_LIST()
3152     }
3153 };
3154 
3155 static const VMStateDescription vmstate_virtio_virtqueues = {
3156     .name = "virtio/virtqueues",
3157     .version_id = 1,
3158     .minimum_version_id = 1,
3159     .needed = &virtio_virtqueue_needed,
3160     .fields = (VMStateField[]) {
3161         VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice,
3162                       VIRTIO_QUEUE_MAX, 0, vmstate_virtqueue, VirtQueue),
3163         VMSTATE_END_OF_LIST()
3164     }
3165 };
3166 
3167 static const VMStateDescription vmstate_virtio_packed_virtqueues = {
3168     .name = "virtio/packed_virtqueues",
3169     .version_id = 1,
3170     .minimum_version_id = 1,
3171     .needed = &virtio_packed_virtqueue_needed,
3172     .fields = (VMStateField[]) {
3173         VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice,
3174                       VIRTIO_QUEUE_MAX, 0, vmstate_packed_virtqueue, VirtQueue),
3175         VMSTATE_END_OF_LIST()
3176     }
3177 };
3178 
3179 static const VMStateDescription vmstate_ringsize = {
3180     .name = "ringsize_state",
3181     .version_id = 1,
3182     .minimum_version_id = 1,
3183     .fields = (VMStateField[]) {
3184         VMSTATE_UINT32(vring.num_default, struct VirtQueue),
3185         VMSTATE_END_OF_LIST()
3186     }
3187 };
3188 
3189 static const VMStateDescription vmstate_virtio_ringsize = {
3190     .name = "virtio/ringsize",
3191     .version_id = 1,
3192     .minimum_version_id = 1,
3193     .needed = &virtio_ringsize_needed,
3194     .fields = (VMStateField[]) {
3195         VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice,
3196                       VIRTIO_QUEUE_MAX, 0, vmstate_ringsize, VirtQueue),
3197         VMSTATE_END_OF_LIST()
3198     }
3199 };
3200 
3201 static int get_extra_state(QEMUFile *f, void *pv, size_t size,
3202                            const VMStateField *field)
3203 {
3204     VirtIODevice *vdev = pv;
3205     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3206     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3207 
3208     if (!k->load_extra_state) {
3209         return -1;
3210     } else {
3211         return k->load_extra_state(qbus->parent, f);
3212     }
3213 }
3214 
3215 static int put_extra_state(QEMUFile *f, void *pv, size_t size,
3216                            const VMStateField *field, JSONWriter *vmdesc)
3217 {
3218     VirtIODevice *vdev = pv;
3219     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3220     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3221 
3222     k->save_extra_state(qbus->parent, f);
3223     return 0;
3224 }
3225 
3226 static const VMStateInfo vmstate_info_extra_state = {
3227     .name = "virtqueue_extra_state",
3228     .get = get_extra_state,
3229     .put = put_extra_state,
3230 };
3231 
3232 static const VMStateDescription vmstate_virtio_extra_state = {
3233     .name = "virtio/extra_state",
3234     .version_id = 1,
3235     .minimum_version_id = 1,
3236     .needed = &virtio_extra_state_needed,
3237     .fields = (VMStateField[]) {
3238         {
3239             .name         = "extra_state",
3240             .version_id   = 0,
3241             .field_exists = NULL,
3242             .size         = 0,
3243             .info         = &vmstate_info_extra_state,
3244             .flags        = VMS_SINGLE,
3245             .offset       = 0,
3246         },
3247         VMSTATE_END_OF_LIST()
3248     }
3249 };
3250 
3251 static const VMStateDescription vmstate_virtio_device_endian = {
3252     .name = "virtio/device_endian",
3253     .version_id = 1,
3254     .minimum_version_id = 1,
3255     .needed = &virtio_device_endian_needed,
3256     .fields = (VMStateField[]) {
3257         VMSTATE_UINT8(device_endian, VirtIODevice),
3258         VMSTATE_END_OF_LIST()
3259     }
3260 };
3261 
3262 static const VMStateDescription vmstate_virtio_64bit_features = {
3263     .name = "virtio/64bit_features",
3264     .version_id = 1,
3265     .minimum_version_id = 1,
3266     .needed = &virtio_64bit_features_needed,
3267     .fields = (VMStateField[]) {
3268         VMSTATE_UINT64(guest_features, VirtIODevice),
3269         VMSTATE_END_OF_LIST()
3270     }
3271 };
3272 
3273 static const VMStateDescription vmstate_virtio_broken = {
3274     .name = "virtio/broken",
3275     .version_id = 1,
3276     .minimum_version_id = 1,
3277     .needed = &virtio_broken_needed,
3278     .fields = (VMStateField[]) {
3279         VMSTATE_BOOL(broken, VirtIODevice),
3280         VMSTATE_END_OF_LIST()
3281     }
3282 };
3283 
3284 static const VMStateDescription vmstate_virtio_started = {
3285     .name = "virtio/started",
3286     .version_id = 1,
3287     .minimum_version_id = 1,
3288     .needed = &virtio_started_needed,
3289     .fields = (VMStateField[]) {
3290         VMSTATE_BOOL(started, VirtIODevice),
3291         VMSTATE_END_OF_LIST()
3292     }
3293 };
3294 
3295 static const VMStateDescription vmstate_virtio_disabled = {
3296     .name = "virtio/disabled",
3297     .version_id = 1,
3298     .minimum_version_id = 1,
3299     .needed = &virtio_disabled_needed,
3300     .fields = (VMStateField[]) {
3301         VMSTATE_BOOL(disabled, VirtIODevice),
3302         VMSTATE_END_OF_LIST()
3303     }
3304 };
3305 
3306 static const VMStateDescription vmstate_virtio = {
3307     .name = "virtio",
3308     .version_id = 1,
3309     .minimum_version_id = 1,
3310     .fields = (VMStateField[]) {
3311         VMSTATE_END_OF_LIST()
3312     },
3313     .subsections = (const VMStateDescription*[]) {
3314         &vmstate_virtio_device_endian,
3315         &vmstate_virtio_64bit_features,
3316         &vmstate_virtio_virtqueues,
3317         &vmstate_virtio_ringsize,
3318         &vmstate_virtio_broken,
3319         &vmstate_virtio_extra_state,
3320         &vmstate_virtio_started,
3321         &vmstate_virtio_packed_virtqueues,
3322         &vmstate_virtio_disabled,
3323         NULL
3324     }
3325 };
3326 
3327 int virtio_save(VirtIODevice *vdev, QEMUFile *f)
3328 {
3329     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3330     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3331     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
3332     uint32_t guest_features_lo = (vdev->guest_features & 0xffffffff);
3333     int i;
3334 
3335     if (k->save_config) {
3336         k->save_config(qbus->parent, f);
3337     }
3338 
3339     qemu_put_8s(f, &vdev->status);
3340     qemu_put_8s(f, &vdev->isr);
3341     qemu_put_be16s(f, &vdev->queue_sel);
3342     qemu_put_be32s(f, &guest_features_lo);
3343     qemu_put_be32(f, vdev->config_len);
3344     qemu_put_buffer(f, vdev->config, vdev->config_len);
3345 
3346     for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
3347         if (vdev->vq[i].vring.num == 0)
3348             break;
3349     }
3350 
3351     qemu_put_be32(f, i);
3352 
3353     for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
3354         if (vdev->vq[i].vring.num == 0)
3355             break;
3356 
3357         qemu_put_be32(f, vdev->vq[i].vring.num);
3358         if (k->has_variable_vring_alignment) {
3359             qemu_put_be32(f, vdev->vq[i].vring.align);
3360         }
3361         /*
3362          * Save desc now, the rest of the ring addresses are saved in
3363          * subsections for VIRTIO-1 devices.
3364          */
3365         qemu_put_be64(f, vdev->vq[i].vring.desc);
3366         qemu_put_be16s(f, &vdev->vq[i].last_avail_idx);
3367         if (k->save_queue) {
3368             k->save_queue(qbus->parent, i, f);
3369         }
3370     }
3371 
3372     if (vdc->save != NULL) {
3373         vdc->save(vdev, f);
3374     }
3375 
3376     if (vdc->vmsd) {
3377         int ret = vmstate_save_state(f, vdc->vmsd, vdev, NULL);
3378         if (ret) {
3379             return ret;
3380         }
3381     }
3382 
3383     /* Subsections */
3384     return vmstate_save_state(f, &vmstate_virtio, vdev, NULL);
3385 }
3386 
3387 /* A wrapper for use as a VMState .put function */
3388 static int virtio_device_put(QEMUFile *f, void *opaque, size_t size,
3389                               const VMStateField *field, JSONWriter *vmdesc)
3390 {
3391     return virtio_save(VIRTIO_DEVICE(opaque), f);
3392 }
3393 
3394 /* A wrapper for use as a VMState .get function */
3395 static int virtio_device_get(QEMUFile *f, void *opaque, size_t size,
3396                              const VMStateField *field)
3397 {
3398     VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
3399     DeviceClass *dc = DEVICE_CLASS(VIRTIO_DEVICE_GET_CLASS(vdev));
3400 
3401     return virtio_load(vdev, f, dc->vmsd->version_id);
3402 }
3403 
3404 const VMStateInfo  virtio_vmstate_info = {
3405     .name = "virtio",
3406     .get = virtio_device_get,
3407     .put = virtio_device_put,
3408 };
3409 
3410 static int virtio_set_features_nocheck(VirtIODevice *vdev, uint64_t val)
3411 {
3412     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
3413     bool bad = (val & ~(vdev->host_features)) != 0;
3414 
3415     val &= vdev->host_features;
3416     if (k->set_features) {
3417         k->set_features(vdev, val);
3418     }
3419     vdev->guest_features = val;
3420     return bad ? -1 : 0;
3421 }
3422 
3423 int virtio_set_features(VirtIODevice *vdev, uint64_t val)
3424 {
3425     int ret;
3426     /*
3427      * The driver must not attempt to set features after feature negotiation
3428      * has finished.
3429      */
3430     if (vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) {
3431         return -EINVAL;
3432     }
3433 
3434     if (val & (1ull << VIRTIO_F_BAD_FEATURE)) {
3435         qemu_log_mask(LOG_GUEST_ERROR,
3436                       "%s: guest driver for %s has enabled UNUSED(30) feature bit!\n",
3437                       __func__, vdev->name);
3438     }
3439 
3440     ret = virtio_set_features_nocheck(vdev, val);
3441     if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
3442         /* VIRTIO_RING_F_EVENT_IDX changes the size of the caches.  */
3443         int i;
3444         for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
3445             if (vdev->vq[i].vring.num != 0) {
3446                 virtio_init_region_cache(vdev, i);
3447             }
3448         }
3449     }
3450     if (!ret) {
3451         if (!virtio_device_started(vdev, vdev->status) &&
3452             !virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
3453             vdev->start_on_kick = true;
3454         }
3455     }
3456     return ret;
3457 }
3458 
3459 size_t virtio_get_config_size(const VirtIOConfigSizeParams *params,
3460                               uint64_t host_features)
3461 {
3462     size_t config_size = params->min_size;
3463     const VirtIOFeature *feature_sizes = params->feature_sizes;
3464     size_t i;
3465 
3466     for (i = 0; feature_sizes[i].flags != 0; i++) {
3467         if (host_features & feature_sizes[i].flags) {
3468             config_size = MAX(feature_sizes[i].end, config_size);
3469         }
3470     }
3471 
3472     assert(config_size <= params->max_size);
3473     return config_size;
3474 }
3475 
3476 int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
3477 {
3478     int i, ret;
3479     int32_t config_len;
3480     uint32_t num;
3481     uint32_t features;
3482     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3483     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3484     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
3485 
3486     /*
3487      * We poison the endianness to ensure it does not get used before
3488      * subsections have been loaded.
3489      */
3490     vdev->device_endian = VIRTIO_DEVICE_ENDIAN_UNKNOWN;
3491 
3492     if (k->load_config) {
3493         ret = k->load_config(qbus->parent, f);
3494         if (ret)
3495             return ret;
3496     }
3497 
3498     qemu_get_8s(f, &vdev->status);
3499     qemu_get_8s(f, &vdev->isr);
3500     qemu_get_be16s(f, &vdev->queue_sel);
3501     if (vdev->queue_sel >= VIRTIO_QUEUE_MAX) {
3502         return -1;
3503     }
3504     qemu_get_be32s(f, &features);
3505 
3506     /*
3507      * Temporarily set guest_features low bits - needed by
3508      * virtio net load code testing for VIRTIO_NET_F_CTRL_GUEST_OFFLOADS
3509      * VIRTIO_NET_F_GUEST_ANNOUNCE and VIRTIO_NET_F_CTRL_VQ.
3510      *
3511      * Note: devices should always test host features in future - don't create
3512      * new dependencies like this.
3513      */
3514     vdev->guest_features = features;
3515 
3516     config_len = qemu_get_be32(f);
3517 
3518     /*
3519      * There are cases where the incoming config can be bigger or smaller
3520      * than what we have; so load what we have space for, and skip
3521      * any excess that's in the stream.
3522      */
3523     qemu_get_buffer(f, vdev->config, MIN(config_len, vdev->config_len));
3524 
3525     while (config_len > vdev->config_len) {
3526         qemu_get_byte(f);
3527         config_len--;
3528     }
3529 
3530     num = qemu_get_be32(f);
3531 
3532     if (num > VIRTIO_QUEUE_MAX) {
3533         error_report("Invalid number of virtqueues: 0x%x", num);
3534         return -1;
3535     }
3536 
3537     for (i = 0; i < num; i++) {
3538         vdev->vq[i].vring.num = qemu_get_be32(f);
3539         if (k->has_variable_vring_alignment) {
3540             vdev->vq[i].vring.align = qemu_get_be32(f);
3541         }
3542         vdev->vq[i].vring.desc = qemu_get_be64(f);
3543         qemu_get_be16s(f, &vdev->vq[i].last_avail_idx);
3544         vdev->vq[i].signalled_used_valid = false;
3545         vdev->vq[i].notification = true;
3546 
3547         if (!vdev->vq[i].vring.desc && vdev->vq[i].last_avail_idx) {
3548             error_report("VQ %d address 0x0 "
3549                          "inconsistent with Host index 0x%x",
3550                          i, vdev->vq[i].last_avail_idx);
3551             return -1;
3552         }
3553         if (k->load_queue) {
3554             ret = k->load_queue(qbus->parent, i, f);
3555             if (ret)
3556                 return ret;
3557         }
3558     }
3559 
3560     virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
3561 
3562     if (vdc->load != NULL) {
3563         ret = vdc->load(vdev, f, version_id);
3564         if (ret) {
3565             return ret;
3566         }
3567     }
3568 
3569     if (vdc->vmsd) {
3570         ret = vmstate_load_state(f, vdc->vmsd, vdev, version_id);
3571         if (ret) {
3572             return ret;
3573         }
3574     }
3575 
3576     /* Subsections */
3577     ret = vmstate_load_state(f, &vmstate_virtio, vdev, 1);
3578     if (ret) {
3579         return ret;
3580     }
3581 
3582     if (vdev->device_endian == VIRTIO_DEVICE_ENDIAN_UNKNOWN) {
3583         vdev->device_endian = virtio_default_endian();
3584     }
3585 
3586     if (virtio_64bit_features_needed(vdev)) {
3587         /*
3588          * Subsection load filled vdev->guest_features.  Run them
3589          * through virtio_set_features to sanity-check them against
3590          * host_features.
3591          */
3592         uint64_t features64 = vdev->guest_features;
3593         if (virtio_set_features_nocheck(vdev, features64) < 0) {
3594             error_report("Features 0x%" PRIx64 " unsupported. "
3595                          "Allowed features: 0x%" PRIx64,
3596                          features64, vdev->host_features);
3597             return -1;
3598         }
3599     } else {
3600         if (virtio_set_features_nocheck(vdev, features) < 0) {
3601             error_report("Features 0x%x unsupported. "
3602                          "Allowed features: 0x%" PRIx64,
3603                          features, vdev->host_features);
3604             return -1;
3605         }
3606     }
3607 
3608     if (!virtio_device_started(vdev, vdev->status) &&
3609         !virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
3610         vdev->start_on_kick = true;
3611     }
3612 
3613     RCU_READ_LOCK_GUARD();
3614     for (i = 0; i < num; i++) {
3615         if (vdev->vq[i].vring.desc) {
3616             uint16_t nheads;
3617 
3618             /*
3619              * VIRTIO-1 devices migrate desc, used, and avail ring addresses so
3620              * only the region cache needs to be set up.  Legacy devices need
3621              * to calculate used and avail ring addresses based on the desc
3622              * address.
3623              */
3624             if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
3625                 virtio_init_region_cache(vdev, i);
3626             } else {
3627                 virtio_queue_update_rings(vdev, i);
3628             }
3629 
3630             if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3631                 vdev->vq[i].shadow_avail_idx = vdev->vq[i].last_avail_idx;
3632                 vdev->vq[i].shadow_avail_wrap_counter =
3633                                         vdev->vq[i].last_avail_wrap_counter;
3634                 continue;
3635             }
3636 
3637             nheads = vring_avail_idx(&vdev->vq[i]) - vdev->vq[i].last_avail_idx;
3638             /* Check it isn't doing strange things with descriptor numbers. */
3639             if (nheads > vdev->vq[i].vring.num) {
3640                 virtio_error(vdev, "VQ %d size 0x%x Guest index 0x%x "
3641                              "inconsistent with Host index 0x%x: delta 0x%x",
3642                              i, vdev->vq[i].vring.num,
3643                              vring_avail_idx(&vdev->vq[i]),
3644                              vdev->vq[i].last_avail_idx, nheads);
3645                 vdev->vq[i].used_idx = 0;
3646                 vdev->vq[i].shadow_avail_idx = 0;
3647                 vdev->vq[i].inuse = 0;
3648                 continue;
3649             }
3650             vdev->vq[i].used_idx = vring_used_idx(&vdev->vq[i]);
3651             vdev->vq[i].shadow_avail_idx = vring_avail_idx(&vdev->vq[i]);
3652 
3653             /*
3654              * Some devices migrate VirtQueueElements that have been popped
3655              * from the avail ring but not yet returned to the used ring.
3656              * Since max ring size < UINT16_MAX it's safe to use modulo
3657              * UINT16_MAX + 1 subtraction.
3658              */
3659             vdev->vq[i].inuse = (uint16_t)(vdev->vq[i].last_avail_idx -
3660                                 vdev->vq[i].used_idx);
3661             if (vdev->vq[i].inuse > vdev->vq[i].vring.num) {
3662                 error_report("VQ %d size 0x%x < last_avail_idx 0x%x - "
3663                              "used_idx 0x%x",
3664                              i, vdev->vq[i].vring.num,
3665                              vdev->vq[i].last_avail_idx,
3666                              vdev->vq[i].used_idx);
3667                 return -1;
3668             }
3669         }
3670     }
3671 
3672     if (vdc->post_load) {
3673         ret = vdc->post_load(vdev);
3674         if (ret) {
3675             return ret;
3676         }
3677     }
3678 
3679     return 0;
3680 }
3681 
3682 void virtio_cleanup(VirtIODevice *vdev)
3683 {
3684     qemu_del_vm_change_state_handler(vdev->vmstate);
3685 }
3686 
3687 static void virtio_vmstate_change(void *opaque, bool running, RunState state)
3688 {
3689     VirtIODevice *vdev = opaque;
3690     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3691     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3692     bool backend_run = running && virtio_device_started(vdev, vdev->status);
3693     vdev->vm_running = running;
3694 
3695     if (backend_run) {
3696         virtio_set_status(vdev, vdev->status);
3697     }
3698 
3699     if (k->vmstate_change) {
3700         k->vmstate_change(qbus->parent, backend_run);
3701     }
3702 
3703     if (!backend_run) {
3704         virtio_set_status(vdev, vdev->status);
3705     }
3706 }
3707 
3708 void virtio_instance_init_common(Object *proxy_obj, void *data,
3709                                  size_t vdev_size, const char *vdev_name)
3710 {
3711     DeviceState *vdev = data;
3712 
3713     object_initialize_child_with_props(proxy_obj, "virtio-backend", vdev,
3714                                        vdev_size, vdev_name, &error_abort,
3715                                        NULL);
3716     qdev_alias_all_properties(vdev, proxy_obj);
3717 }
3718 
3719 void virtio_init(VirtIODevice *vdev, uint16_t device_id, size_t config_size)
3720 {
3721     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3722     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3723     int i;
3724     int nvectors = k->query_nvectors ? k->query_nvectors(qbus->parent) : 0;
3725 
3726     if (nvectors) {
3727         vdev->vector_queues =
3728             g_malloc0(sizeof(*vdev->vector_queues) * nvectors);
3729     }
3730 
3731     vdev->start_on_kick = false;
3732     vdev->started = false;
3733     vdev->vhost_started = false;
3734     vdev->device_id = device_id;
3735     vdev->status = 0;
3736     qatomic_set(&vdev->isr, 0);
3737     vdev->queue_sel = 0;
3738     vdev->config_vector = VIRTIO_NO_VECTOR;
3739     vdev->vq = g_new0(VirtQueue, VIRTIO_QUEUE_MAX);
3740     vdev->vm_running = runstate_is_running();
3741     vdev->broken = false;
3742     for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
3743         vdev->vq[i].vector = VIRTIO_NO_VECTOR;
3744         vdev->vq[i].vdev = vdev;
3745         vdev->vq[i].queue_index = i;
3746         vdev->vq[i].host_notifier_enabled = false;
3747     }
3748 
3749     vdev->name = virtio_id_to_name(device_id);
3750     vdev->config_len = config_size;
3751     if (vdev->config_len) {
3752         vdev->config = g_malloc0(config_size);
3753     } else {
3754         vdev->config = NULL;
3755     }
3756     vdev->vmstate = qdev_add_vm_change_state_handler(DEVICE(vdev),
3757             virtio_vmstate_change, vdev);
3758     vdev->device_endian = virtio_default_endian();
3759     vdev->use_guest_notifier_mask = true;
3760 }
3761 
3762 /*
3763  * Only devices that have already been around prior to defining the virtio
3764  * standard support legacy mode; this includes devices not specified in the
3765  * standard. All newer devices conform to the virtio standard only.
3766  */
3767 bool virtio_legacy_allowed(VirtIODevice *vdev)
3768 {
3769     switch (vdev->device_id) {
3770     case VIRTIO_ID_NET:
3771     case VIRTIO_ID_BLOCK:
3772     case VIRTIO_ID_CONSOLE:
3773     case VIRTIO_ID_RNG:
3774     case VIRTIO_ID_BALLOON:
3775     case VIRTIO_ID_RPMSG:
3776     case VIRTIO_ID_SCSI:
3777     case VIRTIO_ID_9P:
3778     case VIRTIO_ID_RPROC_SERIAL:
3779     case VIRTIO_ID_CAIF:
3780         return true;
3781     default:
3782         return false;
3783     }
3784 }
3785 
3786 bool virtio_legacy_check_disabled(VirtIODevice *vdev)
3787 {
3788     return vdev->disable_legacy_check;
3789 }
3790 
3791 hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n)
3792 {
3793     return vdev->vq[n].vring.desc;
3794 }
3795 
3796 bool virtio_queue_enabled_legacy(VirtIODevice *vdev, int n)
3797 {
3798     return virtio_queue_get_desc_addr(vdev, n) != 0;
3799 }
3800 
3801 bool virtio_queue_enabled(VirtIODevice *vdev, int n)
3802 {
3803     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3804     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3805 
3806     if (k->queue_enabled) {
3807         return k->queue_enabled(qbus->parent, n);
3808     }
3809     return virtio_queue_enabled_legacy(vdev, n);
3810 }
3811 
3812 hwaddr virtio_queue_get_avail_addr(VirtIODevice *vdev, int n)
3813 {
3814     return vdev->vq[n].vring.avail;
3815 }
3816 
3817 hwaddr virtio_queue_get_used_addr(VirtIODevice *vdev, int n)
3818 {
3819     return vdev->vq[n].vring.used;
3820 }
3821 
3822 hwaddr virtio_queue_get_desc_size(VirtIODevice *vdev, int n)
3823 {
3824     return sizeof(VRingDesc) * vdev->vq[n].vring.num;
3825 }
3826 
3827 hwaddr virtio_queue_get_avail_size(VirtIODevice *vdev, int n)
3828 {
3829     int s;
3830 
3831     if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3832         return sizeof(struct VRingPackedDescEvent);
3833     }
3834 
3835     s = virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
3836     return offsetof(VRingAvail, ring) +
3837         sizeof(uint16_t) * vdev->vq[n].vring.num + s;
3838 }
3839 
3840 hwaddr virtio_queue_get_used_size(VirtIODevice *vdev, int n)
3841 {
3842     int s;
3843 
3844     if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3845         return sizeof(struct VRingPackedDescEvent);
3846     }
3847 
3848     s = virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
3849     return offsetof(VRingUsed, ring) +
3850         sizeof(VRingUsedElem) * vdev->vq[n].vring.num + s;
3851 }
3852 
3853 static unsigned int virtio_queue_packed_get_last_avail_idx(VirtIODevice *vdev,
3854                                                            int n)
3855 {
3856     unsigned int avail, used;
3857 
3858     avail = vdev->vq[n].last_avail_idx;
3859     avail |= ((uint16_t)vdev->vq[n].last_avail_wrap_counter) << 15;
3860 
3861     used = vdev->vq[n].used_idx;
3862     used |= ((uint16_t)vdev->vq[n].used_wrap_counter) << 15;
3863 
3864     return avail | used << 16;
3865 }
3866 
3867 static uint16_t virtio_queue_split_get_last_avail_idx(VirtIODevice *vdev,
3868                                                       int n)
3869 {
3870     return vdev->vq[n].last_avail_idx;
3871 }
3872 
3873 unsigned int virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n)
3874 {
3875     if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3876         return virtio_queue_packed_get_last_avail_idx(vdev, n);
3877     } else {
3878         return virtio_queue_split_get_last_avail_idx(vdev, n);
3879     }
3880 }
3881 
3882 static void virtio_queue_packed_set_last_avail_idx(VirtIODevice *vdev,
3883                                                    int n, unsigned int idx)
3884 {
3885     struct VirtQueue *vq = &vdev->vq[n];
3886 
3887     vq->last_avail_idx = vq->shadow_avail_idx = idx & 0x7fff;
3888     vq->last_avail_wrap_counter =
3889         vq->shadow_avail_wrap_counter = !!(idx & 0x8000);
3890     idx >>= 16;
3891     vq->used_idx = idx & 0x7ffff;
3892     vq->used_wrap_counter = !!(idx & 0x8000);
3893 }
3894 
3895 static void virtio_queue_split_set_last_avail_idx(VirtIODevice *vdev,
3896                                                   int n, unsigned int idx)
3897 {
3898         vdev->vq[n].last_avail_idx = idx;
3899         vdev->vq[n].shadow_avail_idx = idx;
3900 }
3901 
3902 void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n,
3903                                      unsigned int idx)
3904 {
3905     if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3906         virtio_queue_packed_set_last_avail_idx(vdev, n, idx);
3907     } else {
3908         virtio_queue_split_set_last_avail_idx(vdev, n, idx);
3909     }
3910 }
3911 
3912 static void virtio_queue_packed_restore_last_avail_idx(VirtIODevice *vdev,
3913                                                        int n)
3914 {
3915     /* We don't have a reference like avail idx in shared memory */
3916     return;
3917 }
3918 
3919 static void virtio_queue_split_restore_last_avail_idx(VirtIODevice *vdev,
3920                                                       int n)
3921 {
3922     RCU_READ_LOCK_GUARD();
3923     if (vdev->vq[n].vring.desc) {
3924         vdev->vq[n].last_avail_idx = vring_used_idx(&vdev->vq[n]);
3925         vdev->vq[n].shadow_avail_idx = vdev->vq[n].last_avail_idx;
3926     }
3927 }
3928 
3929 void virtio_queue_restore_last_avail_idx(VirtIODevice *vdev, int n)
3930 {
3931     if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3932         virtio_queue_packed_restore_last_avail_idx(vdev, n);
3933     } else {
3934         virtio_queue_split_restore_last_avail_idx(vdev, n);
3935     }
3936 }
3937 
3938 static void virtio_queue_packed_update_used_idx(VirtIODevice *vdev, int n)
3939 {
3940     /* used idx was updated through set_last_avail_idx() */
3941     return;
3942 }
3943 
3944 static void virtio_split_packed_update_used_idx(VirtIODevice *vdev, int n)
3945 {
3946     RCU_READ_LOCK_GUARD();
3947     if (vdev->vq[n].vring.desc) {
3948         vdev->vq[n].used_idx = vring_used_idx(&vdev->vq[n]);
3949     }
3950 }
3951 
3952 void virtio_queue_update_used_idx(VirtIODevice *vdev, int n)
3953 {
3954     if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3955         return virtio_queue_packed_update_used_idx(vdev, n);
3956     } else {
3957         return virtio_split_packed_update_used_idx(vdev, n);
3958     }
3959 }
3960 
3961 void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n)
3962 {
3963     vdev->vq[n].signalled_used_valid = false;
3964 }
3965 
3966 VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n)
3967 {
3968     return vdev->vq + n;
3969 }
3970 
3971 uint16_t virtio_get_queue_index(VirtQueue *vq)
3972 {
3973     return vq->queue_index;
3974 }
3975 
3976 static void virtio_queue_guest_notifier_read(EventNotifier *n)
3977 {
3978     VirtQueue *vq = container_of(n, VirtQueue, guest_notifier);
3979     if (event_notifier_test_and_clear(n)) {
3980         virtio_irq(vq);
3981     }
3982 }
3983 
3984 void virtio_queue_set_guest_notifier_fd_handler(VirtQueue *vq, bool assign,
3985                                                 bool with_irqfd)
3986 {
3987     if (assign && !with_irqfd) {
3988         event_notifier_set_handler(&vq->guest_notifier,
3989                                    virtio_queue_guest_notifier_read);
3990     } else {
3991         event_notifier_set_handler(&vq->guest_notifier, NULL);
3992     }
3993     if (!assign) {
3994         /* Test and clear notifier before closing it,
3995          * in case poll callback didn't have time to run. */
3996         virtio_queue_guest_notifier_read(&vq->guest_notifier);
3997     }
3998 }
3999 
4000 EventNotifier *virtio_queue_get_guest_notifier(VirtQueue *vq)
4001 {
4002     return &vq->guest_notifier;
4003 }
4004 
4005 static void virtio_queue_host_notifier_aio_poll_begin(EventNotifier *n)
4006 {
4007     VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
4008 
4009     virtio_queue_set_notification(vq, 0);
4010 }
4011 
4012 static bool virtio_queue_host_notifier_aio_poll(void *opaque)
4013 {
4014     EventNotifier *n = opaque;
4015     VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
4016 
4017     return vq->vring.desc && !virtio_queue_empty(vq);
4018 }
4019 
4020 static void virtio_queue_host_notifier_aio_poll_ready(EventNotifier *n)
4021 {
4022     VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
4023 
4024     virtio_queue_notify_vq(vq);
4025 }
4026 
4027 static void virtio_queue_host_notifier_aio_poll_end(EventNotifier *n)
4028 {
4029     VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
4030 
4031     /* Caller polls once more after this to catch requests that race with us */
4032     virtio_queue_set_notification(vq, 1);
4033 }
4034 
4035 void virtio_queue_aio_attach_host_notifier(VirtQueue *vq, AioContext *ctx)
4036 {
4037     aio_set_event_notifier(ctx, &vq->host_notifier, true,
4038                            virtio_queue_host_notifier_read,
4039                            virtio_queue_host_notifier_aio_poll,
4040                            virtio_queue_host_notifier_aio_poll_ready);
4041     aio_set_event_notifier_poll(ctx, &vq->host_notifier,
4042                                 virtio_queue_host_notifier_aio_poll_begin,
4043                                 virtio_queue_host_notifier_aio_poll_end);
4044 }
4045 
4046 /*
4047  * Same as virtio_queue_aio_attach_host_notifier() but without polling. Use
4048  * this for rx virtqueues and similar cases where the virtqueue handler
4049  * function does not pop all elements. When the virtqueue is left non-empty
4050  * polling consumes CPU cycles and should not be used.
4051  */
4052 void virtio_queue_aio_attach_host_notifier_no_poll(VirtQueue *vq, AioContext *ctx)
4053 {
4054     aio_set_event_notifier(ctx, &vq->host_notifier, true,
4055                            virtio_queue_host_notifier_read,
4056                            NULL, NULL);
4057 }
4058 
4059 void virtio_queue_aio_detach_host_notifier(VirtQueue *vq, AioContext *ctx)
4060 {
4061     aio_set_event_notifier(ctx, &vq->host_notifier, true, NULL, NULL, NULL);
4062     /* Test and clear notifier before after disabling event,
4063      * in case poll callback didn't have time to run. */
4064     virtio_queue_host_notifier_read(&vq->host_notifier);
4065 }
4066 
4067 void virtio_queue_host_notifier_read(EventNotifier *n)
4068 {
4069     VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
4070     if (event_notifier_test_and_clear(n)) {
4071         virtio_queue_notify_vq(vq);
4072     }
4073 }
4074 
4075 EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq)
4076 {
4077     return &vq->host_notifier;
4078 }
4079 
4080 void virtio_queue_set_host_notifier_enabled(VirtQueue *vq, bool enabled)
4081 {
4082     vq->host_notifier_enabled = enabled;
4083 }
4084 
4085 int virtio_queue_set_host_notifier_mr(VirtIODevice *vdev, int n,
4086                                       MemoryRegion *mr, bool assign)
4087 {
4088     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
4089     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
4090 
4091     if (k->set_host_notifier_mr) {
4092         return k->set_host_notifier_mr(qbus->parent, n, mr, assign);
4093     }
4094 
4095     return -1;
4096 }
4097 
4098 void virtio_device_set_child_bus_name(VirtIODevice *vdev, char *bus_name)
4099 {
4100     g_free(vdev->bus_name);
4101     vdev->bus_name = g_strdup(bus_name);
4102 }
4103 
4104 void G_GNUC_PRINTF(2, 3) virtio_error(VirtIODevice *vdev, const char *fmt, ...)
4105 {
4106     va_list ap;
4107 
4108     va_start(ap, fmt);
4109     error_vreport(fmt, ap);
4110     va_end(ap);
4111 
4112     if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
4113         vdev->status = vdev->status | VIRTIO_CONFIG_S_NEEDS_RESET;
4114         virtio_notify_config(vdev);
4115     }
4116 
4117     vdev->broken = true;
4118 }
4119 
4120 static void virtio_memory_listener_commit(MemoryListener *listener)
4121 {
4122     VirtIODevice *vdev = container_of(listener, VirtIODevice, listener);
4123     int i;
4124 
4125     for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
4126         if (vdev->vq[i].vring.num == 0) {
4127             break;
4128         }
4129         virtio_init_region_cache(vdev, i);
4130     }
4131 }
4132 
4133 static void virtio_device_realize(DeviceState *dev, Error **errp)
4134 {
4135     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
4136     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
4137     Error *err = NULL;
4138 
4139     /* Devices should either use vmsd or the load/save methods */
4140     assert(!vdc->vmsd || !vdc->load);
4141 
4142     if (vdc->realize != NULL) {
4143         vdc->realize(dev, &err);
4144         if (err != NULL) {
4145             error_propagate(errp, err);
4146             return;
4147         }
4148     }
4149 
4150     virtio_bus_device_plugged(vdev, &err);
4151     if (err != NULL) {
4152         error_propagate(errp, err);
4153         vdc->unrealize(dev);
4154         return;
4155     }
4156 
4157     vdev->listener.commit = virtio_memory_listener_commit;
4158     vdev->listener.name = "virtio";
4159     memory_listener_register(&vdev->listener, vdev->dma_as);
4160     QTAILQ_INSERT_TAIL(&virtio_list, vdev, next);
4161 }
4162 
4163 static void virtio_device_unrealize(DeviceState *dev)
4164 {
4165     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
4166     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
4167 
4168     memory_listener_unregister(&vdev->listener);
4169     virtio_bus_device_unplugged(vdev);
4170 
4171     if (vdc->unrealize != NULL) {
4172         vdc->unrealize(dev);
4173     }
4174 
4175     QTAILQ_REMOVE(&virtio_list, vdev, next);
4176     g_free(vdev->bus_name);
4177     vdev->bus_name = NULL;
4178 }
4179 
4180 static void virtio_device_free_virtqueues(VirtIODevice *vdev)
4181 {
4182     int i;
4183     if (!vdev->vq) {
4184         return;
4185     }
4186 
4187     for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
4188         if (vdev->vq[i].vring.num == 0) {
4189             break;
4190         }
4191         virtio_virtqueue_reset_region_cache(&vdev->vq[i]);
4192     }
4193     g_free(vdev->vq);
4194 }
4195 
4196 static void virtio_device_instance_finalize(Object *obj)
4197 {
4198     VirtIODevice *vdev = VIRTIO_DEVICE(obj);
4199 
4200     virtio_device_free_virtqueues(vdev);
4201 
4202     g_free(vdev->config);
4203     g_free(vdev->vector_queues);
4204 }
4205 
4206 static Property virtio_properties[] = {
4207     DEFINE_VIRTIO_COMMON_FEATURES(VirtIODevice, host_features),
4208     DEFINE_PROP_BOOL("use-started", VirtIODevice, use_started, true),
4209     DEFINE_PROP_BOOL("use-disabled-flag", VirtIODevice, use_disabled_flag, true),
4210     DEFINE_PROP_BOOL("x-disable-legacy-check", VirtIODevice,
4211                      disable_legacy_check, false),
4212     DEFINE_PROP_END_OF_LIST(),
4213 };
4214 
4215 static int virtio_device_start_ioeventfd_impl(VirtIODevice *vdev)
4216 {
4217     VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev)));
4218     int i, n, r, err;
4219 
4220     /*
4221      * Batch all the host notifiers in a single transaction to avoid
4222      * quadratic time complexity in address_space_update_ioeventfds().
4223      */
4224     memory_region_transaction_begin();
4225     for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
4226         VirtQueue *vq = &vdev->vq[n];
4227         if (!virtio_queue_get_num(vdev, n)) {
4228             continue;
4229         }
4230         r = virtio_bus_set_host_notifier(qbus, n, true);
4231         if (r < 0) {
4232             err = r;
4233             goto assign_error;
4234         }
4235         event_notifier_set_handler(&vq->host_notifier,
4236                                    virtio_queue_host_notifier_read);
4237     }
4238 
4239     for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
4240         /* Kick right away to begin processing requests already in vring */
4241         VirtQueue *vq = &vdev->vq[n];
4242         if (!vq->vring.num) {
4243             continue;
4244         }
4245         event_notifier_set(&vq->host_notifier);
4246     }
4247     memory_region_transaction_commit();
4248     return 0;
4249 
4250 assign_error:
4251     i = n; /* save n for a second iteration after transaction is committed. */
4252     while (--n >= 0) {
4253         VirtQueue *vq = &vdev->vq[n];
4254         if (!virtio_queue_get_num(vdev, n)) {
4255             continue;
4256         }
4257 
4258         event_notifier_set_handler(&vq->host_notifier, NULL);
4259         r = virtio_bus_set_host_notifier(qbus, n, false);
4260         assert(r >= 0);
4261     }
4262     /*
4263      * The transaction expects the ioeventfds to be open when it
4264      * commits. Do it now, before the cleanup loop.
4265      */
4266     memory_region_transaction_commit();
4267 
4268     while (--i >= 0) {
4269         if (!virtio_queue_get_num(vdev, i)) {
4270             continue;
4271         }
4272         virtio_bus_cleanup_host_notifier(qbus, i);
4273     }
4274     return err;
4275 }
4276 
4277 int virtio_device_start_ioeventfd(VirtIODevice *vdev)
4278 {
4279     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
4280     VirtioBusState *vbus = VIRTIO_BUS(qbus);
4281 
4282     return virtio_bus_start_ioeventfd(vbus);
4283 }
4284 
4285 static void virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev)
4286 {
4287     VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev)));
4288     int n, r;
4289 
4290     /*
4291      * Batch all the host notifiers in a single transaction to avoid
4292      * quadratic time complexity in address_space_update_ioeventfds().
4293      */
4294     memory_region_transaction_begin();
4295     for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
4296         VirtQueue *vq = &vdev->vq[n];
4297 
4298         if (!virtio_queue_get_num(vdev, n)) {
4299             continue;
4300         }
4301         event_notifier_set_handler(&vq->host_notifier, NULL);
4302         r = virtio_bus_set_host_notifier(qbus, n, false);
4303         assert(r >= 0);
4304     }
4305     /*
4306      * The transaction expects the ioeventfds to be open when it
4307      * commits. Do it now, before the cleanup loop.
4308      */
4309     memory_region_transaction_commit();
4310 
4311     for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
4312         if (!virtio_queue_get_num(vdev, n)) {
4313             continue;
4314         }
4315         virtio_bus_cleanup_host_notifier(qbus, n);
4316     }
4317 }
4318 
4319 int virtio_device_grab_ioeventfd(VirtIODevice *vdev)
4320 {
4321     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
4322     VirtioBusState *vbus = VIRTIO_BUS(qbus);
4323 
4324     return virtio_bus_grab_ioeventfd(vbus);
4325 }
4326 
4327 void virtio_device_release_ioeventfd(VirtIODevice *vdev)
4328 {
4329     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
4330     VirtioBusState *vbus = VIRTIO_BUS(qbus);
4331 
4332     virtio_bus_release_ioeventfd(vbus);
4333 }
4334 
4335 static void virtio_device_class_init(ObjectClass *klass, void *data)
4336 {
4337     /* Set the default value here. */
4338     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
4339     DeviceClass *dc = DEVICE_CLASS(klass);
4340 
4341     dc->realize = virtio_device_realize;
4342     dc->unrealize = virtio_device_unrealize;
4343     dc->bus_type = TYPE_VIRTIO_BUS;
4344     device_class_set_props(dc, virtio_properties);
4345     vdc->start_ioeventfd = virtio_device_start_ioeventfd_impl;
4346     vdc->stop_ioeventfd = virtio_device_stop_ioeventfd_impl;
4347 
4348     vdc->legacy_features |= VIRTIO_LEGACY_FEATURES;
4349 
4350     QTAILQ_INIT(&virtio_list);
4351 }
4352 
4353 bool virtio_device_ioeventfd_enabled(VirtIODevice *vdev)
4354 {
4355     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
4356     VirtioBusState *vbus = VIRTIO_BUS(qbus);
4357 
4358     return virtio_bus_ioeventfd_enabled(vbus);
4359 }
4360 
4361 VirtioInfoList *qmp_x_query_virtio(Error **errp)
4362 {
4363     VirtioInfoList *list = NULL;
4364     VirtioInfoList *node;
4365     VirtIODevice *vdev;
4366 
4367     QTAILQ_FOREACH(vdev, &virtio_list, next) {
4368         DeviceState *dev = DEVICE(vdev);
4369         Error *err = NULL;
4370         QObject *obj = qmp_qom_get(dev->canonical_path, "realized", &err);
4371 
4372         if (err == NULL) {
4373             GString *is_realized = qobject_to_json_pretty(obj, true);
4374             /* virtio device is NOT realized, remove it from list */
4375             if (!strncmp(is_realized->str, "false", 4)) {
4376                 QTAILQ_REMOVE(&virtio_list, vdev, next);
4377             } else {
4378                 node = g_new0(VirtioInfoList, 1);
4379                 node->value = g_new(VirtioInfo, 1);
4380                 node->value->path = g_strdup(dev->canonical_path);
4381                 node->value->name = g_strdup(vdev->name);
4382                 QAPI_LIST_PREPEND(list, node->value);
4383             }
4384            g_string_free(is_realized, true);
4385         }
4386         qobject_unref(obj);
4387     }
4388 
4389     return list;
4390 }
4391 
4392 static VirtIODevice *virtio_device_find(const char *path)
4393 {
4394     VirtIODevice *vdev;
4395 
4396     QTAILQ_FOREACH(vdev, &virtio_list, next) {
4397         DeviceState *dev = DEVICE(vdev);
4398 
4399         if (strcmp(dev->canonical_path, path) != 0) {
4400             continue;
4401         }
4402 
4403         Error *err = NULL;
4404         QObject *obj = qmp_qom_get(dev->canonical_path, "realized", &err);
4405         if (err == NULL) {
4406             GString *is_realized = qobject_to_json_pretty(obj, true);
4407             /* virtio device is NOT realized, remove it from list */
4408             if (!strncmp(is_realized->str, "false", 4)) {
4409                 g_string_free(is_realized, true);
4410                 qobject_unref(obj);
4411                 QTAILQ_REMOVE(&virtio_list, vdev, next);
4412                 return NULL;
4413             }
4414             g_string_free(is_realized, true);
4415         } else {
4416             /* virtio device doesn't exist in QOM tree */
4417             QTAILQ_REMOVE(&virtio_list, vdev, next);
4418             qobject_unref(obj);
4419             return NULL;
4420         }
4421         /* device exists in QOM tree & is realized */
4422         qobject_unref(obj);
4423         return vdev;
4424     }
4425     return NULL;
4426 }
4427 
4428 #define CONVERT_FEATURES(type, map, is_status, bitmap)   \
4429     ({                                                   \
4430         type *list = NULL;                               \
4431         type *node;                                      \
4432         for (i = 0; map[i].virtio_bit != -1; i++) {      \
4433             if (is_status) {                             \
4434                 bit = map[i].virtio_bit;                 \
4435             }                                            \
4436             else {                                       \
4437                 bit = 1ULL << map[i].virtio_bit;         \
4438             }                                            \
4439             if ((bitmap & bit) == 0) {                   \
4440                 continue;                                \
4441             }                                            \
4442             node = g_new0(type, 1);                      \
4443             node->value = g_strdup(map[i].feature_desc); \
4444             node->next = list;                           \
4445             list = node;                                 \
4446             bitmap ^= bit;                               \
4447         }                                                \
4448         list;                                            \
4449     })
4450 
4451 static VirtioDeviceStatus *qmp_decode_status(uint8_t bitmap)
4452 {
4453     VirtioDeviceStatus *status;
4454     uint8_t bit;
4455     int i;
4456 
4457     status = g_new0(VirtioDeviceStatus, 1);
4458     status->statuses = CONVERT_FEATURES(strList, virtio_config_status_map,
4459                                         1, bitmap);
4460     status->has_unknown_statuses = bitmap != 0;
4461     if (status->has_unknown_statuses) {
4462         status->unknown_statuses = bitmap;
4463     }
4464 
4465     return status;
4466 }
4467 
4468 static VhostDeviceProtocols *qmp_decode_protocols(uint64_t bitmap)
4469 {
4470     VhostDeviceProtocols *vhu_protocols;
4471     uint64_t bit;
4472     int i;
4473 
4474     vhu_protocols = g_new0(VhostDeviceProtocols, 1);
4475     vhu_protocols->protocols =
4476                     CONVERT_FEATURES(strList,
4477                                      vhost_user_protocol_map, 0, bitmap);
4478     vhu_protocols->has_unknown_protocols = bitmap != 0;
4479     if (vhu_protocols->has_unknown_protocols) {
4480         vhu_protocols->unknown_protocols = bitmap;
4481     }
4482 
4483     return vhu_protocols;
4484 }
4485 
4486 static VirtioDeviceFeatures *qmp_decode_features(uint16_t device_id,
4487                                                  uint64_t bitmap)
4488 {
4489     VirtioDeviceFeatures *features;
4490     uint64_t bit;
4491     int i;
4492 
4493     features = g_new0(VirtioDeviceFeatures, 1);
4494     features->has_dev_features = true;
4495 
4496     /* transport features */
4497     features->transports = CONVERT_FEATURES(strList, virtio_transport_map, 0,
4498                                             bitmap);
4499 
4500     /* device features */
4501     switch (device_id) {
4502 #ifdef CONFIG_VIRTIO_SERIAL
4503     case VIRTIO_ID_CONSOLE:
4504         features->dev_features =
4505             CONVERT_FEATURES(strList, virtio_serial_feature_map, 0, bitmap);
4506         break;
4507 #endif
4508 #ifdef CONFIG_VIRTIO_BLK
4509     case VIRTIO_ID_BLOCK:
4510         features->dev_features =
4511             CONVERT_FEATURES(strList, virtio_blk_feature_map, 0, bitmap);
4512         break;
4513 #endif
4514 #ifdef CONFIG_VIRTIO_GPU
4515     case VIRTIO_ID_GPU:
4516         features->dev_features =
4517             CONVERT_FEATURES(strList, virtio_gpu_feature_map, 0, bitmap);
4518         break;
4519 #endif
4520 #ifdef CONFIG_VIRTIO_NET
4521     case VIRTIO_ID_NET:
4522         features->dev_features =
4523             CONVERT_FEATURES(strList, virtio_net_feature_map, 0, bitmap);
4524         break;
4525 #endif
4526 #ifdef CONFIG_VIRTIO_SCSI
4527     case VIRTIO_ID_SCSI:
4528         features->dev_features =
4529             CONVERT_FEATURES(strList, virtio_scsi_feature_map, 0, bitmap);
4530         break;
4531 #endif
4532 #ifdef CONFIG_VIRTIO_BALLOON
4533     case VIRTIO_ID_BALLOON:
4534         features->dev_features =
4535             CONVERT_FEATURES(strList, virtio_balloon_feature_map, 0, bitmap);
4536         break;
4537 #endif
4538 #ifdef CONFIG_VIRTIO_IOMMU
4539     case VIRTIO_ID_IOMMU:
4540         features->dev_features =
4541             CONVERT_FEATURES(strList, virtio_iommu_feature_map, 0, bitmap);
4542         break;
4543 #endif
4544 #ifdef CONFIG_VIRTIO_INPUT
4545     case VIRTIO_ID_INPUT:
4546         features->dev_features =
4547             CONVERT_FEATURES(strList, virtio_input_feature_map, 0, bitmap);
4548         break;
4549 #endif
4550 #ifdef CONFIG_VHOST_USER_FS
4551     case VIRTIO_ID_FS:
4552         features->dev_features =
4553             CONVERT_FEATURES(strList, virtio_fs_feature_map, 0, bitmap);
4554         break;
4555 #endif
4556 #ifdef CONFIG_VHOST_VSOCK
4557     case VIRTIO_ID_VSOCK:
4558         features->dev_features =
4559             CONVERT_FEATURES(strList, virtio_vsock_feature_map, 0, bitmap);
4560         break;
4561 #endif
4562 #ifdef CONFIG_VIRTIO_CRYPTO
4563     case VIRTIO_ID_CRYPTO:
4564         features->dev_features =
4565             CONVERT_FEATURES(strList, virtio_crypto_feature_map, 0, bitmap);
4566         break;
4567 #endif
4568 #ifdef CONFIG_VIRTIO_MEM
4569     case VIRTIO_ID_MEM:
4570         features->dev_features =
4571             CONVERT_FEATURES(strList, virtio_mem_feature_map, 0, bitmap);
4572         break;
4573 #endif
4574 #ifdef CONFIG_VIRTIO_I2C_ADAPTER
4575     case VIRTIO_ID_I2C_ADAPTER:
4576         features->dev_features =
4577             CONVERT_FEATURES(strList, virtio_i2c_feature_map, 0, bitmap);
4578         break;
4579 #endif
4580 #ifdef CONFIG_VIRTIO_RNG
4581     case VIRTIO_ID_RNG:
4582         features->dev_features =
4583             CONVERT_FEATURES(strList, virtio_rng_feature_map, 0, bitmap);
4584         break;
4585 #endif
4586     /* No features */
4587     case VIRTIO_ID_9P:
4588     case VIRTIO_ID_PMEM:
4589     case VIRTIO_ID_IOMEM:
4590     case VIRTIO_ID_RPMSG:
4591     case VIRTIO_ID_CLOCK:
4592     case VIRTIO_ID_MAC80211_WLAN:
4593     case VIRTIO_ID_MAC80211_HWSIM:
4594     case VIRTIO_ID_RPROC_SERIAL:
4595     case VIRTIO_ID_MEMORY_BALLOON:
4596     case VIRTIO_ID_CAIF:
4597     case VIRTIO_ID_SIGNAL_DIST:
4598     case VIRTIO_ID_PSTORE:
4599     case VIRTIO_ID_SOUND:
4600     case VIRTIO_ID_BT:
4601     case VIRTIO_ID_RPMB:
4602     case VIRTIO_ID_VIDEO_ENCODER:
4603     case VIRTIO_ID_VIDEO_DECODER:
4604     case VIRTIO_ID_SCMI:
4605     case VIRTIO_ID_NITRO_SEC_MOD:
4606     case VIRTIO_ID_WATCHDOG:
4607     case VIRTIO_ID_CAN:
4608     case VIRTIO_ID_DMABUF:
4609     case VIRTIO_ID_PARAM_SERV:
4610     case VIRTIO_ID_AUDIO_POLICY:
4611     case VIRTIO_ID_GPIO:
4612         break;
4613     default:
4614         g_assert_not_reached();
4615     }
4616 
4617     features->has_unknown_dev_features = bitmap != 0;
4618     if (features->has_unknown_dev_features) {
4619         features->unknown_dev_features = bitmap;
4620     }
4621 
4622     return features;
4623 }
4624 
4625 VirtioStatus *qmp_x_query_virtio_status(const char *path, Error **errp)
4626 {
4627     VirtIODevice *vdev;
4628     VirtioStatus *status;
4629 
4630     vdev = virtio_device_find(path);
4631     if (vdev == NULL) {
4632         error_setg(errp, "Path %s is not a VirtIODevice", path);
4633         return NULL;
4634     }
4635 
4636     status = g_new0(VirtioStatus, 1);
4637     status->name = g_strdup(vdev->name);
4638     status->device_id = vdev->device_id;
4639     status->vhost_started = vdev->vhost_started;
4640     status->guest_features = qmp_decode_features(vdev->device_id,
4641                                                  vdev->guest_features);
4642     status->host_features = qmp_decode_features(vdev->device_id,
4643                                                 vdev->host_features);
4644     status->backend_features = qmp_decode_features(vdev->device_id,
4645                                                    vdev->backend_features);
4646 
4647     switch (vdev->device_endian) {
4648     case VIRTIO_DEVICE_ENDIAN_LITTLE:
4649         status->device_endian = g_strdup("little");
4650         break;
4651     case VIRTIO_DEVICE_ENDIAN_BIG:
4652         status->device_endian = g_strdup("big");
4653         break;
4654     default:
4655         status->device_endian = g_strdup("unknown");
4656         break;
4657     }
4658 
4659     status->num_vqs = virtio_get_num_queues(vdev);
4660     status->status = qmp_decode_status(vdev->status);
4661     status->isr = vdev->isr;
4662     status->queue_sel = vdev->queue_sel;
4663     status->vm_running = vdev->vm_running;
4664     status->broken = vdev->broken;
4665     status->disabled = vdev->disabled;
4666     status->use_started = vdev->use_started;
4667     status->started = vdev->started;
4668     status->start_on_kick = vdev->start_on_kick;
4669     status->disable_legacy_check = vdev->disable_legacy_check;
4670     status->bus_name = g_strdup(vdev->bus_name);
4671     status->use_guest_notifier_mask = vdev->use_guest_notifier_mask;
4672     status->has_vhost_dev = vdev->vhost_started;
4673 
4674     if (vdev->vhost_started) {
4675         VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
4676         struct vhost_dev *hdev = vdc->get_vhost(vdev);
4677 
4678         status->vhost_dev = g_new0(VhostStatus, 1);
4679         status->vhost_dev->n_mem_sections = hdev->n_mem_sections;
4680         status->vhost_dev->n_tmp_sections = hdev->n_tmp_sections;
4681         status->vhost_dev->nvqs = hdev->nvqs;
4682         status->vhost_dev->vq_index = hdev->vq_index;
4683         status->vhost_dev->features =
4684             qmp_decode_features(vdev->device_id, hdev->features);
4685         status->vhost_dev->acked_features =
4686             qmp_decode_features(vdev->device_id, hdev->acked_features);
4687         status->vhost_dev->backend_features =
4688             qmp_decode_features(vdev->device_id, hdev->backend_features);
4689         status->vhost_dev->protocol_features =
4690             qmp_decode_protocols(hdev->protocol_features);
4691         status->vhost_dev->max_queues = hdev->max_queues;
4692         status->vhost_dev->backend_cap = hdev->backend_cap;
4693         status->vhost_dev->log_enabled = hdev->log_enabled;
4694         status->vhost_dev->log_size = hdev->log_size;
4695     }
4696 
4697     return status;
4698 }
4699 
4700 VirtVhostQueueStatus *qmp_x_query_virtio_vhost_queue_status(const char *path,
4701                                                             uint16_t queue,
4702                                                             Error **errp)
4703 {
4704     VirtIODevice *vdev;
4705     VirtVhostQueueStatus *status;
4706 
4707     vdev = virtio_device_find(path);
4708     if (vdev == NULL) {
4709         error_setg(errp, "Path %s is not a VirtIODevice", path);
4710         return NULL;
4711     }
4712 
4713     if (!vdev->vhost_started) {
4714         error_setg(errp, "Error: vhost device has not started yet");
4715         return NULL;
4716     }
4717 
4718     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
4719     struct vhost_dev *hdev = vdc->get_vhost(vdev);
4720 
4721     if (queue < hdev->vq_index || queue >= hdev->vq_index + hdev->nvqs) {
4722         error_setg(errp, "Invalid vhost virtqueue number %d", queue);
4723         return NULL;
4724     }
4725 
4726     status = g_new0(VirtVhostQueueStatus, 1);
4727     status->name = g_strdup(vdev->name);
4728     status->kick = hdev->vqs[queue].kick;
4729     status->call = hdev->vqs[queue].call;
4730     status->desc = (uintptr_t)hdev->vqs[queue].desc;
4731     status->avail = (uintptr_t)hdev->vqs[queue].avail;
4732     status->used = (uintptr_t)hdev->vqs[queue].used;
4733     status->num = hdev->vqs[queue].num;
4734     status->desc_phys = hdev->vqs[queue].desc_phys;
4735     status->desc_size = hdev->vqs[queue].desc_size;
4736     status->avail_phys = hdev->vqs[queue].avail_phys;
4737     status->avail_size = hdev->vqs[queue].avail_size;
4738     status->used_phys = hdev->vqs[queue].used_phys;
4739     status->used_size = hdev->vqs[queue].used_size;
4740 
4741     return status;
4742 }
4743 
4744 VirtQueueStatus *qmp_x_query_virtio_queue_status(const char *path,
4745                                                  uint16_t queue,
4746                                                  Error **errp)
4747 {
4748     VirtIODevice *vdev;
4749     VirtQueueStatus *status;
4750 
4751     vdev = virtio_device_find(path);
4752     if (vdev == NULL) {
4753         error_setg(errp, "Path %s is not a VirtIODevice", path);
4754         return NULL;
4755     }
4756 
4757     if (queue >= VIRTIO_QUEUE_MAX || !virtio_queue_get_num(vdev, queue)) {
4758         error_setg(errp, "Invalid virtqueue number %d", queue);
4759         return NULL;
4760     }
4761 
4762     status = g_new0(VirtQueueStatus, 1);
4763     status->name = g_strdup(vdev->name);
4764     status->queue_index = vdev->vq[queue].queue_index;
4765     status->inuse = vdev->vq[queue].inuse;
4766     status->vring_num = vdev->vq[queue].vring.num;
4767     status->vring_num_default = vdev->vq[queue].vring.num_default;
4768     status->vring_align = vdev->vq[queue].vring.align;
4769     status->vring_desc = vdev->vq[queue].vring.desc;
4770     status->vring_avail = vdev->vq[queue].vring.avail;
4771     status->vring_used = vdev->vq[queue].vring.used;
4772     status->used_idx = vdev->vq[queue].used_idx;
4773     status->signalled_used = vdev->vq[queue].signalled_used;
4774     status->signalled_used_valid = vdev->vq[queue].signalled_used_valid;
4775 
4776     if (vdev->vhost_started) {
4777         VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
4778         struct vhost_dev *hdev = vdc->get_vhost(vdev);
4779 
4780         /* check if vq index exists for vhost as well  */
4781         if (queue >= hdev->vq_index && queue < hdev->vq_index + hdev->nvqs) {
4782             status->has_last_avail_idx = true;
4783 
4784             int vhost_vq_index =
4785                 hdev->vhost_ops->vhost_get_vq_index(hdev, queue);
4786             struct vhost_vring_state state = {
4787                 .index = vhost_vq_index,
4788             };
4789 
4790             status->last_avail_idx =
4791                 hdev->vhost_ops->vhost_get_vring_base(hdev, &state);
4792         }
4793     } else {
4794         status->has_shadow_avail_idx = true;
4795         status->has_last_avail_idx = true;
4796         status->last_avail_idx = vdev->vq[queue].last_avail_idx;
4797         status->shadow_avail_idx = vdev->vq[queue].shadow_avail_idx;
4798     }
4799 
4800     return status;
4801 }
4802 
4803 static strList *qmp_decode_vring_desc_flags(uint16_t flags)
4804 {
4805     strList *list = NULL;
4806     strList *node;
4807     int i;
4808 
4809     struct {
4810         uint16_t flag;
4811         const char *value;
4812     } map[] = {
4813         { VRING_DESC_F_NEXT, "next" },
4814         { VRING_DESC_F_WRITE, "write" },
4815         { VRING_DESC_F_INDIRECT, "indirect" },
4816         { 1 << VRING_PACKED_DESC_F_AVAIL, "avail" },
4817         { 1 << VRING_PACKED_DESC_F_USED, "used" },
4818         { 0, "" }
4819     };
4820 
4821     for (i = 0; map[i].flag; i++) {
4822         if ((map[i].flag & flags) == 0) {
4823             continue;
4824         }
4825         node = g_malloc0(sizeof(strList));
4826         node->value = g_strdup(map[i].value);
4827         node->next = list;
4828         list = node;
4829     }
4830 
4831     return list;
4832 }
4833 
4834 VirtioQueueElement *qmp_x_query_virtio_queue_element(const char *path,
4835                                                      uint16_t queue,
4836                                                      bool has_index,
4837                                                      uint16_t index,
4838                                                      Error **errp)
4839 {
4840     VirtIODevice *vdev;
4841     VirtQueue *vq;
4842     VirtioQueueElement *element = NULL;
4843 
4844     vdev = virtio_device_find(path);
4845     if (vdev == NULL) {
4846         error_setg(errp, "Path %s is not a VirtIO device", path);
4847         return NULL;
4848     }
4849 
4850     if (queue >= VIRTIO_QUEUE_MAX || !virtio_queue_get_num(vdev, queue)) {
4851         error_setg(errp, "Invalid virtqueue number %d", queue);
4852         return NULL;
4853     }
4854     vq = &vdev->vq[queue];
4855 
4856     if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
4857         error_setg(errp, "Packed ring not supported");
4858         return NULL;
4859     } else {
4860         unsigned int head, i, max;
4861         VRingMemoryRegionCaches *caches;
4862         MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
4863         MemoryRegionCache *desc_cache;
4864         VRingDesc desc;
4865         VirtioRingDescList *list = NULL;
4866         VirtioRingDescList *node;
4867         int rc; int ndescs;
4868 
4869         RCU_READ_LOCK_GUARD();
4870 
4871         max = vq->vring.num;
4872 
4873         if (!has_index) {
4874             head = vring_avail_ring(vq, vq->last_avail_idx % vq->vring.num);
4875         } else {
4876             head = vring_avail_ring(vq, index % vq->vring.num);
4877         }
4878         i = head;
4879 
4880         caches = vring_get_region_caches(vq);
4881         if (!caches) {
4882             error_setg(errp, "Region caches not initialized");
4883             return NULL;
4884         }
4885         if (caches->desc.len < max * sizeof(VRingDesc)) {
4886             error_setg(errp, "Cannot map descriptor ring");
4887             return NULL;
4888         }
4889 
4890         desc_cache = &caches->desc;
4891         vring_split_desc_read(vdev, &desc, desc_cache, i);
4892         if (desc.flags & VRING_DESC_F_INDIRECT) {
4893             int64_t len;
4894             len = address_space_cache_init(&indirect_desc_cache, vdev->dma_as,
4895                                            desc.addr, desc.len, false);
4896             desc_cache = &indirect_desc_cache;
4897             if (len < desc.len) {
4898                 error_setg(errp, "Cannot map indirect buffer");
4899                 goto done;
4900             }
4901 
4902             max = desc.len / sizeof(VRingDesc);
4903             i = 0;
4904             vring_split_desc_read(vdev, &desc, desc_cache, i);
4905         }
4906 
4907         element = g_new0(VirtioQueueElement, 1);
4908         element->avail = g_new0(VirtioRingAvail, 1);
4909         element->used = g_new0(VirtioRingUsed, 1);
4910         element->name = g_strdup(vdev->name);
4911         element->index = head;
4912         element->avail->flags = vring_avail_flags(vq);
4913         element->avail->idx = vring_avail_idx(vq);
4914         element->avail->ring = head;
4915         element->used->flags = vring_used_flags(vq);
4916         element->used->idx = vring_used_idx(vq);
4917         ndescs = 0;
4918 
4919         do {
4920             /* A buggy driver may produce an infinite loop */
4921             if (ndescs >= max) {
4922                 break;
4923             }
4924             node = g_new0(VirtioRingDescList, 1);
4925             node->value = g_new0(VirtioRingDesc, 1);
4926             node->value->addr = desc.addr;
4927             node->value->len = desc.len;
4928             node->value->flags = qmp_decode_vring_desc_flags(desc.flags);
4929             node->next = list;
4930             list = node;
4931 
4932             ndescs++;
4933             rc = virtqueue_split_read_next_desc(vdev, &desc, desc_cache,
4934                                                 max, &i);
4935         } while (rc == VIRTQUEUE_READ_DESC_MORE);
4936         element->descs = list;
4937 done:
4938         address_space_cache_destroy(&indirect_desc_cache);
4939     }
4940 
4941     return element;
4942 }
4943 
4944 static const TypeInfo virtio_device_info = {
4945     .name = TYPE_VIRTIO_DEVICE,
4946     .parent = TYPE_DEVICE,
4947     .instance_size = sizeof(VirtIODevice),
4948     .class_init = virtio_device_class_init,
4949     .instance_finalize = virtio_device_instance_finalize,
4950     .abstract = true,
4951     .class_size = sizeof(VirtioDeviceClass),
4952 };
4953 
4954 static void virtio_register_types(void)
4955 {
4956     type_register_static(&virtio_device_info);
4957 }
4958 
4959 type_init(virtio_register_types)
4960