1 /*
2 * Vhost-user filesystem virtio device
3 *
4 * Copyright 2018-2019 Red Hat, Inc.
5 *
6 * Authors:
7 * Stefan Hajnoczi <stefanha@redhat.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2 or
10 * (at your option) any later version. See the COPYING file in the
11 * top-level directory.
12 */
13
14 #include "qemu/osdep.h"
15 #include <sys/ioctl.h>
16 #include "standard-headers/linux/virtio_fs.h"
17 #include "qapi/error.h"
18 #include "hw/qdev-properties.h"
19 #include "hw/qdev-properties-system.h"
20 #include "hw/virtio/virtio-bus.h"
21 #include "hw/virtio/virtio-access.h"
22 #include "qemu/error-report.h"
23 #include "hw/virtio/vhost.h"
24 #include "hw/virtio/vhost-user-fs.h"
25 #include "monitor/monitor.h"
26 #include "sysemu/sysemu.h"
27
28 static const int user_feature_bits[] = {
29 VIRTIO_F_VERSION_1,
30 VIRTIO_RING_F_INDIRECT_DESC,
31 VIRTIO_RING_F_EVENT_IDX,
32 VIRTIO_F_NOTIFY_ON_EMPTY,
33 VIRTIO_F_RING_PACKED,
34 VIRTIO_F_IOMMU_PLATFORM,
35 VIRTIO_F_RING_RESET,
36 VIRTIO_F_IN_ORDER,
37 VIRTIO_F_NOTIFICATION_DATA,
38 VHOST_INVALID_FEATURE_BIT
39 };
40
vuf_get_config(VirtIODevice * vdev,uint8_t * config)41 static void vuf_get_config(VirtIODevice *vdev, uint8_t *config)
42 {
43 VHostUserFS *fs = VHOST_USER_FS(vdev);
44 struct virtio_fs_config fscfg = {};
45
46 memcpy((char *)fscfg.tag, fs->conf.tag,
47 MIN(strlen(fs->conf.tag) + 1, sizeof(fscfg.tag)));
48
49 virtio_stl_p(vdev, &fscfg.num_request_queues, fs->conf.num_request_queues);
50
51 memcpy(config, &fscfg, sizeof(fscfg));
52 }
53
vuf_start(VirtIODevice * vdev)54 static void vuf_start(VirtIODevice *vdev)
55 {
56 VHostUserFS *fs = VHOST_USER_FS(vdev);
57 BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
58 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
59 int ret;
60 int i;
61
62 if (!k->set_guest_notifiers) {
63 error_report("binding does not support guest notifiers");
64 return;
65 }
66
67 ret = vhost_dev_enable_notifiers(&fs->vhost_dev, vdev);
68 if (ret < 0) {
69 error_report("Error enabling host notifiers: %d", -ret);
70 return;
71 }
72
73 ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, true);
74 if (ret < 0) {
75 error_report("Error binding guest notifier: %d", -ret);
76 goto err_host_notifiers;
77 }
78
79 fs->vhost_dev.acked_features = vdev->guest_features;
80 ret = vhost_dev_start(&fs->vhost_dev, vdev, true);
81 if (ret < 0) {
82 error_report("Error starting vhost: %d", -ret);
83 goto err_guest_notifiers;
84 }
85
86 /*
87 * guest_notifier_mask/pending not used yet, so just unmask
88 * everything here. virtio-pci will do the right thing by
89 * enabling/disabling irqfd.
90 */
91 for (i = 0; i < fs->vhost_dev.nvqs; i++) {
92 vhost_virtqueue_mask(&fs->vhost_dev, vdev, i, false);
93 }
94
95 return;
96
97 err_guest_notifiers:
98 k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
99 err_host_notifiers:
100 vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
101 }
102
vuf_stop(VirtIODevice * vdev)103 static void vuf_stop(VirtIODevice *vdev)
104 {
105 VHostUserFS *fs = VHOST_USER_FS(vdev);
106 BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
107 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
108 int ret;
109
110 if (!k->set_guest_notifiers) {
111 return;
112 }
113
114 vhost_dev_stop(&fs->vhost_dev, vdev, true);
115
116 ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
117 if (ret < 0) {
118 error_report("vhost guest notifier cleanup failed: %d", ret);
119 return;
120 }
121
122 vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
123 }
124
vuf_set_status(VirtIODevice * vdev,uint8_t status)125 static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
126 {
127 VHostUserFS *fs = VHOST_USER_FS(vdev);
128 bool should_start = virtio_device_should_start(vdev, status);
129
130 if (vhost_dev_is_started(&fs->vhost_dev) == should_start) {
131 return;
132 }
133
134 if (should_start) {
135 vuf_start(vdev);
136 } else {
137 vuf_stop(vdev);
138 }
139 }
140
vuf_get_features(VirtIODevice * vdev,uint64_t features,Error ** errp)141 static uint64_t vuf_get_features(VirtIODevice *vdev,
142 uint64_t features,
143 Error **errp)
144 {
145 VHostUserFS *fs = VHOST_USER_FS(vdev);
146
147 return vhost_get_features(&fs->vhost_dev, user_feature_bits, features);
148 }
149
vuf_handle_output(VirtIODevice * vdev,VirtQueue * vq)150 static void vuf_handle_output(VirtIODevice *vdev, VirtQueue *vq)
151 {
152 /*
153 * Not normally called; it's the daemon that handles the queue;
154 * however virtio's cleanup path can call this.
155 */
156 }
157
vuf_guest_notifier_mask(VirtIODevice * vdev,int idx,bool mask)158 static void vuf_guest_notifier_mask(VirtIODevice *vdev, int idx,
159 bool mask)
160 {
161 VHostUserFS *fs = VHOST_USER_FS(vdev);
162
163 /*
164 * Add the check for configure interrupt, Use VIRTIO_CONFIG_IRQ_IDX -1
165 * as the macro of configure interrupt's IDX, If this driver does not
166 * support, the function will return
167 */
168
169 if (idx == VIRTIO_CONFIG_IRQ_IDX) {
170 return;
171 }
172 vhost_virtqueue_mask(&fs->vhost_dev, vdev, idx, mask);
173 }
174
vuf_guest_notifier_pending(VirtIODevice * vdev,int idx)175 static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
176 {
177 VHostUserFS *fs = VHOST_USER_FS(vdev);
178
179 /*
180 * Add the check for configure interrupt, Use VIRTIO_CONFIG_IRQ_IDX -1
181 * as the macro of configure interrupt's IDX, If this driver does not
182 * support, the function will return
183 */
184
185 if (idx == VIRTIO_CONFIG_IRQ_IDX) {
186 return false;
187 }
188 return vhost_virtqueue_pending(&fs->vhost_dev, idx);
189 }
190
vuf_device_realize(DeviceState * dev,Error ** errp)191 static void vuf_device_realize(DeviceState *dev, Error **errp)
192 {
193 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
194 VHostUserFS *fs = VHOST_USER_FS(dev);
195 unsigned int i;
196 size_t len;
197 int ret;
198
199 if (!fs->conf.chardev.chr) {
200 error_setg(errp, "missing chardev");
201 return;
202 }
203
204 if (!fs->conf.tag) {
205 error_setg(errp, "missing tag property");
206 return;
207 }
208 len = strlen(fs->conf.tag);
209 if (len == 0) {
210 error_setg(errp, "tag property cannot be empty");
211 return;
212 }
213 if (len > sizeof_field(struct virtio_fs_config, tag)) {
214 error_setg(errp, "tag property must be %zu bytes or less",
215 sizeof_field(struct virtio_fs_config, tag));
216 return;
217 }
218
219 if (fs->conf.num_request_queues == 0) {
220 error_setg(errp, "num-request-queues property must be larger than 0");
221 return;
222 }
223
224 if (!is_power_of_2(fs->conf.queue_size)) {
225 error_setg(errp, "queue-size property must be a power of 2");
226 return;
227 }
228
229 if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
230 error_setg(errp, "queue-size property must be %u or smaller",
231 VIRTQUEUE_MAX_SIZE);
232 return;
233 }
234
235 if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) {
236 return;
237 }
238
239 virtio_init(vdev, VIRTIO_ID_FS, sizeof(struct virtio_fs_config));
240
241 /* Hiprio queue */
242 fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
243
244 /* Request queues */
245 fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues);
246 for (i = 0; i < fs->conf.num_request_queues; i++) {
247 fs->req_vqs[i] = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
248 }
249
250 /* 1 high prio queue, plus the number configured */
251 fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
252 fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
253 ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
254 VHOST_BACKEND_TYPE_USER, 0, errp);
255 if (ret < 0) {
256 goto err_virtio;
257 }
258
259 return;
260
261 err_virtio:
262 vhost_user_cleanup(&fs->vhost_user);
263 virtio_delete_queue(fs->hiprio_vq);
264 for (i = 0; i < fs->conf.num_request_queues; i++) {
265 virtio_delete_queue(fs->req_vqs[i]);
266 }
267 g_free(fs->req_vqs);
268 virtio_cleanup(vdev);
269 g_free(fs->vhost_dev.vqs);
270 return;
271 }
272
vuf_device_unrealize(DeviceState * dev)273 static void vuf_device_unrealize(DeviceState *dev)
274 {
275 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
276 VHostUserFS *fs = VHOST_USER_FS(dev);
277 struct vhost_virtqueue *vhost_vqs = fs->vhost_dev.vqs;
278 int i;
279
280 /* This will stop vhost backend if appropriate. */
281 vuf_set_status(vdev, 0);
282
283 vhost_dev_cleanup(&fs->vhost_dev);
284
285 vhost_user_cleanup(&fs->vhost_user);
286
287 virtio_delete_queue(fs->hiprio_vq);
288 for (i = 0; i < fs->conf.num_request_queues; i++) {
289 virtio_delete_queue(fs->req_vqs[i]);
290 }
291 g_free(fs->req_vqs);
292 virtio_cleanup(vdev);
293 g_free(vhost_vqs);
294 }
295
vuf_get_vhost(VirtIODevice * vdev)296 static struct vhost_dev *vuf_get_vhost(VirtIODevice *vdev)
297 {
298 VHostUserFS *fs = VHOST_USER_FS(vdev);
299 return &fs->vhost_dev;
300 }
301
302 /**
303 * Fetch the internal state from virtiofsd and save it to `f`.
304 */
vuf_save_state(QEMUFile * f,void * pv,size_t size,const VMStateField * field,JSONWriter * vmdesc)305 static int vuf_save_state(QEMUFile *f, void *pv, size_t size,
306 const VMStateField *field, JSONWriter *vmdesc)
307 {
308 VirtIODevice *vdev = pv;
309 VHostUserFS *fs = VHOST_USER_FS(vdev);
310 Error *local_error = NULL;
311 int ret;
312
313 ret = vhost_save_backend_state(&fs->vhost_dev, f, &local_error);
314 if (ret < 0) {
315 error_reportf_err(local_error,
316 "Error saving back-end state of %s device %s "
317 "(tag: \"%s\"): ",
318 vdev->name, vdev->parent_obj.canonical_path,
319 fs->conf.tag ?: "<none>");
320 return ret;
321 }
322
323 return 0;
324 }
325
326 /**
327 * Load virtiofsd's internal state from `f` and send it over to virtiofsd.
328 */
vuf_load_state(QEMUFile * f,void * pv,size_t size,const VMStateField * field)329 static int vuf_load_state(QEMUFile *f, void *pv, size_t size,
330 const VMStateField *field)
331 {
332 VirtIODevice *vdev = pv;
333 VHostUserFS *fs = VHOST_USER_FS(vdev);
334 Error *local_error = NULL;
335 int ret;
336
337 ret = vhost_load_backend_state(&fs->vhost_dev, f, &local_error);
338 if (ret < 0) {
339 error_reportf_err(local_error,
340 "Error loading back-end state of %s device %s "
341 "(tag: \"%s\"): ",
342 vdev->name, vdev->parent_obj.canonical_path,
343 fs->conf.tag ?: "<none>");
344 return ret;
345 }
346
347 return 0;
348 }
349
vuf_is_internal_migration(void * opaque)350 static bool vuf_is_internal_migration(void *opaque)
351 {
352 /* TODO: Return false when an external migration is requested */
353 return true;
354 }
355
vuf_check_migration_support(void * opaque)356 static int vuf_check_migration_support(void *opaque)
357 {
358 VirtIODevice *vdev = opaque;
359 VHostUserFS *fs = VHOST_USER_FS(vdev);
360
361 if (!vhost_supports_device_state(&fs->vhost_dev)) {
362 error_report("Back-end of %s device %s (tag: \"%s\") does not support "
363 "migration through qemu",
364 vdev->name, vdev->parent_obj.canonical_path,
365 fs->conf.tag ?: "<none>");
366 return -ENOTSUP;
367 }
368
369 return 0;
370 }
371
372 static const VMStateDescription vuf_backend_vmstate;
373
374 static const VMStateDescription vuf_vmstate = {
375 .name = "vhost-user-fs",
376 .version_id = 0,
377 .fields = (const VMStateField[]) {
378 VMSTATE_VIRTIO_DEVICE,
379 VMSTATE_END_OF_LIST()
380 },
381 .subsections = (const VMStateDescription * const []) {
382 &vuf_backend_vmstate,
383 NULL,
384 }
385 };
386
387 static const VMStateDescription vuf_backend_vmstate = {
388 .name = "vhost-user-fs-backend",
389 .version_id = 0,
390 .needed = vuf_is_internal_migration,
391 .pre_load = vuf_check_migration_support,
392 .pre_save = vuf_check_migration_support,
393 .fields = (const VMStateField[]) {
394 {
395 .name = "back-end",
396 .info = &(const VMStateInfo) {
397 .name = "virtio-fs back-end state",
398 .get = vuf_load_state,
399 .put = vuf_save_state,
400 },
401 },
402 VMSTATE_END_OF_LIST()
403 },
404 };
405
406 static Property vuf_properties[] = {
407 DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
408 DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
409 DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
410 conf.num_request_queues, 1),
411 DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
412 DEFINE_PROP_END_OF_LIST(),
413 };
414
vuf_instance_init(Object * obj)415 static void vuf_instance_init(Object *obj)
416 {
417 VHostUserFS *fs = VHOST_USER_FS(obj);
418
419 device_add_bootindex_property(obj, &fs->bootindex, "bootindex",
420 "/filesystem@0", DEVICE(obj));
421 }
422
vuf_class_init(ObjectClass * klass,void * data)423 static void vuf_class_init(ObjectClass *klass, void *data)
424 {
425 DeviceClass *dc = DEVICE_CLASS(klass);
426 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
427
428 device_class_set_props(dc, vuf_properties);
429 dc->vmsd = &vuf_vmstate;
430 set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
431 vdc->realize = vuf_device_realize;
432 vdc->unrealize = vuf_device_unrealize;
433 vdc->get_features = vuf_get_features;
434 vdc->get_config = vuf_get_config;
435 vdc->set_status = vuf_set_status;
436 vdc->guest_notifier_mask = vuf_guest_notifier_mask;
437 vdc->guest_notifier_pending = vuf_guest_notifier_pending;
438 vdc->get_vhost = vuf_get_vhost;
439 }
440
441 static const TypeInfo vuf_info = {
442 .name = TYPE_VHOST_USER_FS,
443 .parent = TYPE_VIRTIO_DEVICE,
444 .instance_size = sizeof(VHostUserFS),
445 .instance_init = vuf_instance_init,
446 .class_init = vuf_class_init,
447 };
448
vuf_register_types(void)449 static void vuf_register_types(void)
450 {
451 type_register_static(&vuf_info);
452 }
453
454 type_init(vuf_register_types)
455