xref: /openbmc/qemu/hw/misc/ivshmem.c (revision 2dbb1308)
1 /*
2  * Inter-VM Shared Memory PCI device.
3  *
4  * Author:
5  *      Cam Macdonell <cam@cs.ualberta.ca>
6  *
7  * Based On: cirrus_vga.c
8  *          Copyright (c) 2004 Fabrice Bellard
9  *          Copyright (c) 2004 Makoto Suzuki (suzu)
10  *
11  *      and rtl8139.c
12  *          Copyright (c) 2006 Igor Kovalenko
13  *
14  * This code is licensed under the GNU GPL v2.
15  *
16  * Contributions after 2012-01-13 are licensed under the terms of the
17  * GNU GPL, version 2 or (at your option) any later version.
18  */
19 
20 #include "qemu/osdep.h"
21 #include "qemu/units.h"
22 #include "qapi/error.h"
23 #include "qemu/cutils.h"
24 #include "hw/pci/pci.h"
25 #include "hw/qdev-properties.h"
26 #include "hw/pci/msi.h"
27 #include "hw/pci/msix.h"
28 #include "sysemu/kvm.h"
29 #include "migration/blocker.h"
30 #include "migration/vmstate.h"
31 #include "qemu/error-report.h"
32 #include "qemu/event_notifier.h"
33 #include "qemu/module.h"
34 #include "qom/object_interfaces.h"
35 #include "chardev/char-fe.h"
36 #include "sysemu/hostmem.h"
37 #include "sysemu/qtest.h"
38 #include "qapi/visitor.h"
39 
40 #include "hw/misc/ivshmem.h"
41 #include "qom/object.h"
42 
43 #define PCI_VENDOR_ID_IVSHMEM   PCI_VENDOR_ID_REDHAT_QUMRANET
44 #define PCI_DEVICE_ID_IVSHMEM   0x1110
45 
46 #define IVSHMEM_MAX_PEERS UINT16_MAX
47 #define IVSHMEM_IOEVENTFD   0
48 #define IVSHMEM_MSI     1
49 
50 #define IVSHMEM_REG_BAR_SIZE 0x100
51 
52 #define IVSHMEM_DEBUG 0
53 #define IVSHMEM_DPRINTF(fmt, ...)                       \
54     do {                                                \
55         if (IVSHMEM_DEBUG) {                            \
56             printf("IVSHMEM: " fmt, ## __VA_ARGS__);    \
57         }                                               \
58     } while (0)
59 
60 #define TYPE_IVSHMEM_COMMON "ivshmem-common"
61 typedef struct IVShmemState IVShmemState;
62 DECLARE_INSTANCE_CHECKER(IVShmemState, IVSHMEM_COMMON,
63                          TYPE_IVSHMEM_COMMON)
64 
65 #define TYPE_IVSHMEM_PLAIN "ivshmem-plain"
66 DECLARE_INSTANCE_CHECKER(IVShmemState, IVSHMEM_PLAIN,
67                          TYPE_IVSHMEM_PLAIN)
68 
69 #define TYPE_IVSHMEM_DOORBELL "ivshmem-doorbell"
70 DECLARE_INSTANCE_CHECKER(IVShmemState, IVSHMEM_DOORBELL,
71                          TYPE_IVSHMEM_DOORBELL)
72 
73 #define TYPE_IVSHMEM "ivshmem"
74 DECLARE_INSTANCE_CHECKER(IVShmemState, IVSHMEM,
75                          TYPE_IVSHMEM)
76 
77 typedef struct Peer {
78     int nb_eventfds;
79     EventNotifier *eventfds;
80 } Peer;
81 
82 typedef struct MSIVector {
83     PCIDevice *pdev;
84     int virq;
85     bool unmasked;
86 } MSIVector;
87 
88 struct IVShmemState {
89     /*< private >*/
90     PCIDevice parent_obj;
91     /*< public >*/
92 
93     uint32_t features;
94 
95     /* exactly one of these two may be set */
96     HostMemoryBackend *hostmem; /* with interrupts */
97     CharBackend server_chr; /* without interrupts */
98 
99     /* registers */
100     uint32_t intrmask;
101     uint32_t intrstatus;
102     int vm_id;
103 
104     /* BARs */
105     MemoryRegion ivshmem_mmio;  /* BAR 0 (registers) */
106     MemoryRegion *ivshmem_bar2; /* BAR 2 (shared memory) */
107     MemoryRegion server_bar2;   /* used with server_chr */
108 
109     /* interrupt support */
110     Peer *peers;
111     int nb_peers;               /* space in @peers[] */
112     uint32_t vectors;
113     MSIVector *msi_vectors;
114     uint64_t msg_buf;           /* buffer for receiving server messages */
115     int msg_buffered_bytes;     /* #bytes in @msg_buf */
116 
117     /* migration stuff */
118     OnOffAuto master;
119     Error *migration_blocker;
120 };
121 
122 /* registers for the Inter-VM shared memory device */
123 enum ivshmem_registers {
124     INTRMASK = 0,
125     INTRSTATUS = 4,
126     IVPOSITION = 8,
127     DOORBELL = 12,
128 };
129 
130 static inline uint32_t ivshmem_has_feature(IVShmemState *ivs,
131                                                     unsigned int feature) {
132     return (ivs->features & (1 << feature));
133 }
134 
135 static inline bool ivshmem_is_master(IVShmemState *s)
136 {
137     assert(s->master != ON_OFF_AUTO_AUTO);
138     return s->master == ON_OFF_AUTO_ON;
139 }
140 
141 static void ivshmem_IntrMask_write(IVShmemState *s, uint32_t val)
142 {
143     IVSHMEM_DPRINTF("IntrMask write(w) val = 0x%04x\n", val);
144 
145     s->intrmask = val;
146 }
147 
148 static uint32_t ivshmem_IntrMask_read(IVShmemState *s)
149 {
150     uint32_t ret = s->intrmask;
151 
152     IVSHMEM_DPRINTF("intrmask read(w) val = 0x%04x\n", ret);
153     return ret;
154 }
155 
156 static void ivshmem_IntrStatus_write(IVShmemState *s, uint32_t val)
157 {
158     IVSHMEM_DPRINTF("IntrStatus write(w) val = 0x%04x\n", val);
159 
160     s->intrstatus = val;
161 }
162 
163 static uint32_t ivshmem_IntrStatus_read(IVShmemState *s)
164 {
165     uint32_t ret = s->intrstatus;
166 
167     /* reading ISR clears all interrupts */
168     s->intrstatus = 0;
169     return ret;
170 }
171 
172 static void ivshmem_io_write(void *opaque, hwaddr addr,
173                              uint64_t val, unsigned size)
174 {
175     IVShmemState *s = opaque;
176 
177     uint16_t dest = val >> 16;
178     uint16_t vector = val & 0xff;
179 
180     addr &= 0xfc;
181 
182     IVSHMEM_DPRINTF("writing to addr " TARGET_FMT_plx "\n", addr);
183     switch (addr)
184     {
185         case INTRMASK:
186             ivshmem_IntrMask_write(s, val);
187             break;
188 
189         case INTRSTATUS:
190             ivshmem_IntrStatus_write(s, val);
191             break;
192 
193         case DOORBELL:
194             /* check that dest VM ID is reasonable */
195             if (dest >= s->nb_peers) {
196                 IVSHMEM_DPRINTF("Invalid destination VM ID (%d)\n", dest);
197                 break;
198             }
199 
200             /* check doorbell range */
201             if (vector < s->peers[dest].nb_eventfds) {
202                 IVSHMEM_DPRINTF("Notifying VM %d on vector %d\n", dest, vector);
203                 event_notifier_set(&s->peers[dest].eventfds[vector]);
204             } else {
205                 IVSHMEM_DPRINTF("Invalid destination vector %d on VM %d\n",
206                                 vector, dest);
207             }
208             break;
209         default:
210             IVSHMEM_DPRINTF("Unhandled write " TARGET_FMT_plx "\n", addr);
211     }
212 }
213 
214 static uint64_t ivshmem_io_read(void *opaque, hwaddr addr,
215                                 unsigned size)
216 {
217 
218     IVShmemState *s = opaque;
219     uint32_t ret;
220 
221     switch (addr)
222     {
223         case INTRMASK:
224             ret = ivshmem_IntrMask_read(s);
225             break;
226 
227         case INTRSTATUS:
228             ret = ivshmem_IntrStatus_read(s);
229             break;
230 
231         case IVPOSITION:
232             ret = s->vm_id;
233             break;
234 
235         default:
236             IVSHMEM_DPRINTF("why are we reading " TARGET_FMT_plx "\n", addr);
237             ret = 0;
238     }
239 
240     return ret;
241 }
242 
243 static const MemoryRegionOps ivshmem_mmio_ops = {
244     .read = ivshmem_io_read,
245     .write = ivshmem_io_write,
246     .endianness = DEVICE_NATIVE_ENDIAN,
247     .impl = {
248         .min_access_size = 4,
249         .max_access_size = 4,
250     },
251 };
252 
253 static void ivshmem_vector_notify(void *opaque)
254 {
255     MSIVector *entry = opaque;
256     PCIDevice *pdev = entry->pdev;
257     IVShmemState *s = IVSHMEM_COMMON(pdev);
258     int vector = entry - s->msi_vectors;
259     EventNotifier *n = &s->peers[s->vm_id].eventfds[vector];
260 
261     if (!event_notifier_test_and_clear(n)) {
262         return;
263     }
264 
265     IVSHMEM_DPRINTF("interrupt on vector %p %d\n", pdev, vector);
266     if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
267         if (msix_enabled(pdev)) {
268             msix_notify(pdev, vector);
269         }
270     } else {
271         ivshmem_IntrStatus_write(s, 1);
272     }
273 }
274 
275 static int ivshmem_vector_unmask(PCIDevice *dev, unsigned vector,
276                                  MSIMessage msg)
277 {
278     IVShmemState *s = IVSHMEM_COMMON(dev);
279     EventNotifier *n = &s->peers[s->vm_id].eventfds[vector];
280     MSIVector *v = &s->msi_vectors[vector];
281     int ret;
282 
283     IVSHMEM_DPRINTF("vector unmask %p %d\n", dev, vector);
284     if (!v->pdev) {
285         error_report("ivshmem: vector %d route does not exist", vector);
286         return -EINVAL;
287     }
288     assert(!v->unmasked);
289 
290     ret = kvm_irqchip_update_msi_route(kvm_state, v->virq, msg, dev);
291     if (ret < 0) {
292         return ret;
293     }
294     kvm_irqchip_commit_routes(kvm_state);
295 
296     ret = kvm_irqchip_add_irqfd_notifier_gsi(kvm_state, n, NULL, v->virq);
297     if (ret < 0) {
298         return ret;
299     }
300     v->unmasked = true;
301 
302     return 0;
303 }
304 
305 static void ivshmem_vector_mask(PCIDevice *dev, unsigned vector)
306 {
307     IVShmemState *s = IVSHMEM_COMMON(dev);
308     EventNotifier *n = &s->peers[s->vm_id].eventfds[vector];
309     MSIVector *v = &s->msi_vectors[vector];
310     int ret;
311 
312     IVSHMEM_DPRINTF("vector mask %p %d\n", dev, vector);
313     if (!v->pdev) {
314         error_report("ivshmem: vector %d route does not exist", vector);
315         return;
316     }
317     assert(v->unmasked);
318 
319     ret = kvm_irqchip_remove_irqfd_notifier_gsi(kvm_state, n, v->virq);
320     if (ret < 0) {
321         error_report("remove_irqfd_notifier_gsi failed");
322         return;
323     }
324     v->unmasked = false;
325 }
326 
327 static void ivshmem_vector_poll(PCIDevice *dev,
328                                 unsigned int vector_start,
329                                 unsigned int vector_end)
330 {
331     IVShmemState *s = IVSHMEM_COMMON(dev);
332     unsigned int vector;
333 
334     IVSHMEM_DPRINTF("vector poll %p %d-%d\n", dev, vector_start, vector_end);
335 
336     vector_end = MIN(vector_end, s->vectors);
337 
338     for (vector = vector_start; vector < vector_end; vector++) {
339         EventNotifier *notifier = &s->peers[s->vm_id].eventfds[vector];
340 
341         if (!msix_is_masked(dev, vector)) {
342             continue;
343         }
344 
345         if (event_notifier_test_and_clear(notifier)) {
346             msix_set_pending(dev, vector);
347         }
348     }
349 }
350 
351 static void watch_vector_notifier(IVShmemState *s, EventNotifier *n,
352                                  int vector)
353 {
354     int eventfd = event_notifier_get_fd(n);
355 
356     assert(!s->msi_vectors[vector].pdev);
357     s->msi_vectors[vector].pdev = PCI_DEVICE(s);
358 
359     qemu_set_fd_handler(eventfd, ivshmem_vector_notify,
360                         NULL, &s->msi_vectors[vector]);
361 }
362 
363 static void ivshmem_add_eventfd(IVShmemState *s, int posn, int i)
364 {
365     memory_region_add_eventfd(&s->ivshmem_mmio,
366                               DOORBELL,
367                               4,
368                               true,
369                               (posn << 16) | i,
370                               &s->peers[posn].eventfds[i]);
371 }
372 
373 static void ivshmem_del_eventfd(IVShmemState *s, int posn, int i)
374 {
375     memory_region_del_eventfd(&s->ivshmem_mmio,
376                               DOORBELL,
377                               4,
378                               true,
379                               (posn << 16) | i,
380                               &s->peers[posn].eventfds[i]);
381 }
382 
383 static void close_peer_eventfds(IVShmemState *s, int posn)
384 {
385     int i, n;
386 
387     assert(posn >= 0 && posn < s->nb_peers);
388     n = s->peers[posn].nb_eventfds;
389 
390     if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) {
391         memory_region_transaction_begin();
392         for (i = 0; i < n; i++) {
393             ivshmem_del_eventfd(s, posn, i);
394         }
395         memory_region_transaction_commit();
396     }
397 
398     for (i = 0; i < n; i++) {
399         event_notifier_cleanup(&s->peers[posn].eventfds[i]);
400     }
401 
402     g_free(s->peers[posn].eventfds);
403     s->peers[posn].nb_eventfds = 0;
404 }
405 
406 static void resize_peers(IVShmemState *s, int nb_peers)
407 {
408     int old_nb_peers = s->nb_peers;
409     int i;
410 
411     assert(nb_peers > old_nb_peers);
412     IVSHMEM_DPRINTF("bumping storage to %d peers\n", nb_peers);
413 
414     s->peers = g_realloc(s->peers, nb_peers * sizeof(Peer));
415     s->nb_peers = nb_peers;
416 
417     for (i = old_nb_peers; i < nb_peers; i++) {
418         s->peers[i].eventfds = g_new0(EventNotifier, s->vectors);
419         s->peers[i].nb_eventfds = 0;
420     }
421 }
422 
423 static void ivshmem_add_kvm_msi_virq(IVShmemState *s, int vector,
424                                      Error **errp)
425 {
426     PCIDevice *pdev = PCI_DEVICE(s);
427     int ret;
428 
429     IVSHMEM_DPRINTF("ivshmem_add_kvm_msi_virq vector:%d\n", vector);
430     assert(!s->msi_vectors[vector].pdev);
431 
432     ret = kvm_irqchip_add_msi_route(kvm_state, vector, pdev);
433     if (ret < 0) {
434         error_setg(errp, "kvm_irqchip_add_msi_route failed");
435         return;
436     }
437 
438     s->msi_vectors[vector].virq = ret;
439     s->msi_vectors[vector].pdev = pdev;
440 }
441 
442 static void setup_interrupt(IVShmemState *s, int vector, Error **errp)
443 {
444     EventNotifier *n = &s->peers[s->vm_id].eventfds[vector];
445     bool with_irqfd = kvm_msi_via_irqfd_enabled() &&
446         ivshmem_has_feature(s, IVSHMEM_MSI);
447     PCIDevice *pdev = PCI_DEVICE(s);
448     Error *err = NULL;
449 
450     IVSHMEM_DPRINTF("setting up interrupt for vector: %d\n", vector);
451 
452     if (!with_irqfd) {
453         IVSHMEM_DPRINTF("with eventfd\n");
454         watch_vector_notifier(s, n, vector);
455     } else if (msix_enabled(pdev)) {
456         IVSHMEM_DPRINTF("with irqfd\n");
457         ivshmem_add_kvm_msi_virq(s, vector, &err);
458         if (err) {
459             error_propagate(errp, err);
460             return;
461         }
462 
463         if (!msix_is_masked(pdev, vector)) {
464             kvm_irqchip_add_irqfd_notifier_gsi(kvm_state, n, NULL,
465                                                s->msi_vectors[vector].virq);
466             /* TODO handle error */
467         }
468     } else {
469         /* it will be delayed until msix is enabled, in write_config */
470         IVSHMEM_DPRINTF("with irqfd, delayed until msix enabled\n");
471     }
472 }
473 
474 static void process_msg_shmem(IVShmemState *s, int fd, Error **errp)
475 {
476     Error *local_err = NULL;
477     struct stat buf;
478     size_t size;
479 
480     if (s->ivshmem_bar2) {
481         error_setg(errp, "server sent unexpected shared memory message");
482         close(fd);
483         return;
484     }
485 
486     if (fstat(fd, &buf) < 0) {
487         error_setg_errno(errp, errno,
488             "can't determine size of shared memory sent by server");
489         close(fd);
490         return;
491     }
492 
493     size = buf.st_size;
494 
495     /* mmap the region and map into the BAR2 */
496     memory_region_init_ram_from_fd(&s->server_bar2, OBJECT(s),
497                                    "ivshmem.bar2", size, true, fd, &local_err);
498     if (local_err) {
499         error_propagate(errp, local_err);
500         return;
501     }
502 
503     s->ivshmem_bar2 = &s->server_bar2;
504 }
505 
506 static void process_msg_disconnect(IVShmemState *s, uint16_t posn,
507                                    Error **errp)
508 {
509     IVSHMEM_DPRINTF("posn %d has gone away\n", posn);
510     if (posn >= s->nb_peers || posn == s->vm_id) {
511         error_setg(errp, "invalid peer %d", posn);
512         return;
513     }
514     close_peer_eventfds(s, posn);
515 }
516 
517 static void process_msg_connect(IVShmemState *s, uint16_t posn, int fd,
518                                 Error **errp)
519 {
520     Peer *peer = &s->peers[posn];
521     int vector;
522 
523     /*
524      * The N-th connect message for this peer comes with the file
525      * descriptor for vector N-1.  Count messages to find the vector.
526      */
527     if (peer->nb_eventfds >= s->vectors) {
528         error_setg(errp, "Too many eventfd received, device has %d vectors",
529                    s->vectors);
530         close(fd);
531         return;
532     }
533     vector = peer->nb_eventfds++;
534 
535     IVSHMEM_DPRINTF("eventfds[%d][%d] = %d\n", posn, vector, fd);
536     event_notifier_init_fd(&peer->eventfds[vector], fd);
537     fcntl_setfl(fd, O_NONBLOCK); /* msix/irqfd poll non block */
538 
539     if (posn == s->vm_id) {
540         setup_interrupt(s, vector, errp);
541         /* TODO do we need to handle the error? */
542     }
543 
544     if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) {
545         ivshmem_add_eventfd(s, posn, vector);
546     }
547 }
548 
549 static void process_msg(IVShmemState *s, int64_t msg, int fd, Error **errp)
550 {
551     IVSHMEM_DPRINTF("posn is %" PRId64 ", fd is %d\n", msg, fd);
552 
553     if (msg < -1 || msg > IVSHMEM_MAX_PEERS) {
554         error_setg(errp, "server sent invalid message %" PRId64, msg);
555         close(fd);
556         return;
557     }
558 
559     if (msg == -1) {
560         process_msg_shmem(s, fd, errp);
561         return;
562     }
563 
564     if (msg >= s->nb_peers) {
565         resize_peers(s, msg + 1);
566     }
567 
568     if (fd >= 0) {
569         process_msg_connect(s, msg, fd, errp);
570     } else {
571         process_msg_disconnect(s, msg, errp);
572     }
573 }
574 
575 static int ivshmem_can_receive(void *opaque)
576 {
577     IVShmemState *s = opaque;
578 
579     assert(s->msg_buffered_bytes < sizeof(s->msg_buf));
580     return sizeof(s->msg_buf) - s->msg_buffered_bytes;
581 }
582 
583 static void ivshmem_read(void *opaque, const uint8_t *buf, int size)
584 {
585     IVShmemState *s = opaque;
586     Error *err = NULL;
587     int fd;
588     int64_t msg;
589 
590     assert(size >= 0 && s->msg_buffered_bytes + size <= sizeof(s->msg_buf));
591     memcpy((unsigned char *)&s->msg_buf + s->msg_buffered_bytes, buf, size);
592     s->msg_buffered_bytes += size;
593     if (s->msg_buffered_bytes < sizeof(s->msg_buf)) {
594         return;
595     }
596     msg = le64_to_cpu(s->msg_buf);
597     s->msg_buffered_bytes = 0;
598 
599     fd = qemu_chr_fe_get_msgfd(&s->server_chr);
600 
601     process_msg(s, msg, fd, &err);
602     if (err) {
603         error_report_err(err);
604     }
605 }
606 
607 static int64_t ivshmem_recv_msg(IVShmemState *s, int *pfd, Error **errp)
608 {
609     int64_t msg;
610     int n, ret;
611 
612     n = 0;
613     do {
614         ret = qemu_chr_fe_read_all(&s->server_chr, (uint8_t *)&msg + n,
615                                    sizeof(msg) - n);
616         if (ret < 0) {
617             if (ret == -EINTR) {
618                 continue;
619             }
620             error_setg_errno(errp, -ret, "read from server failed");
621             return INT64_MIN;
622         }
623         n += ret;
624     } while (n < sizeof(msg));
625 
626     *pfd = qemu_chr_fe_get_msgfd(&s->server_chr);
627     return le64_to_cpu(msg);
628 }
629 
630 static void ivshmem_recv_setup(IVShmemState *s, Error **errp)
631 {
632     Error *err = NULL;
633     int64_t msg;
634     int fd;
635 
636     msg = ivshmem_recv_msg(s, &fd, &err);
637     if (err) {
638         error_propagate(errp, err);
639         return;
640     }
641     if (msg != IVSHMEM_PROTOCOL_VERSION) {
642         error_setg(errp, "server sent version %" PRId64 ", expecting %d",
643                    msg, IVSHMEM_PROTOCOL_VERSION);
644         return;
645     }
646     if (fd != -1) {
647         error_setg(errp, "server sent invalid version message");
648         return;
649     }
650 
651     /*
652      * ivshmem-server sends the remaining initial messages in a fixed
653      * order, but the device has always accepted them in any order.
654      * Stay as compatible as practical, just in case people use
655      * servers that behave differently.
656      */
657 
658     /*
659      * ivshmem_device_spec.txt has always required the ID message
660      * right here, and ivshmem-server has always complied.  However,
661      * older versions of the device accepted it out of order, but
662      * broke when an interrupt setup message arrived before it.
663      */
664     msg = ivshmem_recv_msg(s, &fd, &err);
665     if (err) {
666         error_propagate(errp, err);
667         return;
668     }
669     if (fd != -1 || msg < 0 || msg > IVSHMEM_MAX_PEERS) {
670         error_setg(errp, "server sent invalid ID message");
671         return;
672     }
673     s->vm_id = msg;
674 
675     /*
676      * Receive more messages until we got shared memory.
677      */
678     do {
679         msg = ivshmem_recv_msg(s, &fd, &err);
680         if (err) {
681             error_propagate(errp, err);
682             return;
683         }
684         process_msg(s, msg, fd, &err);
685         if (err) {
686             error_propagate(errp, err);
687             return;
688         }
689     } while (msg != -1);
690 
691     /*
692      * This function must either map the shared memory or fail.  The
693      * loop above ensures that: it terminates normally only after it
694      * successfully processed the server's shared memory message.
695      * Assert that actually mapped the shared memory:
696      */
697     assert(s->ivshmem_bar2);
698 }
699 
700 /* Select the MSI-X vectors used by device.
701  * ivshmem maps events to vectors statically, so
702  * we just enable all vectors on init and after reset. */
703 static void ivshmem_msix_vector_use(IVShmemState *s)
704 {
705     PCIDevice *d = PCI_DEVICE(s);
706     int i;
707 
708     for (i = 0; i < s->vectors; i++) {
709         msix_vector_use(d, i);
710     }
711 }
712 
713 static void ivshmem_disable_irqfd(IVShmemState *s);
714 
715 static void ivshmem_reset(DeviceState *d)
716 {
717     IVShmemState *s = IVSHMEM_COMMON(d);
718 
719     ivshmem_disable_irqfd(s);
720 
721     s->intrstatus = 0;
722     s->intrmask = 0;
723     if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
724         ivshmem_msix_vector_use(s);
725     }
726 }
727 
728 static int ivshmem_setup_interrupts(IVShmemState *s, Error **errp)
729 {
730     /* allocate QEMU callback data for receiving interrupts */
731     s->msi_vectors = g_malloc0(s->vectors * sizeof(MSIVector));
732 
733     if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
734         if (msix_init_exclusive_bar(PCI_DEVICE(s), s->vectors, 1, errp)) {
735             return -1;
736         }
737 
738         IVSHMEM_DPRINTF("msix initialized (%d vectors)\n", s->vectors);
739         ivshmem_msix_vector_use(s);
740     }
741 
742     return 0;
743 }
744 
745 static void ivshmem_remove_kvm_msi_virq(IVShmemState *s, int vector)
746 {
747     IVSHMEM_DPRINTF("ivshmem_remove_kvm_msi_virq vector:%d\n", vector);
748 
749     if (s->msi_vectors[vector].pdev == NULL) {
750         return;
751     }
752 
753     /* it was cleaned when masked in the frontend. */
754     kvm_irqchip_release_virq(kvm_state, s->msi_vectors[vector].virq);
755 
756     s->msi_vectors[vector].pdev = NULL;
757 }
758 
759 static void ivshmem_enable_irqfd(IVShmemState *s)
760 {
761     PCIDevice *pdev = PCI_DEVICE(s);
762     int i;
763 
764     for (i = 0; i < s->peers[s->vm_id].nb_eventfds; i++) {
765         Error *err = NULL;
766 
767         ivshmem_add_kvm_msi_virq(s, i, &err);
768         if (err) {
769             error_report_err(err);
770             goto undo;
771         }
772     }
773 
774     if (msix_set_vector_notifiers(pdev,
775                                   ivshmem_vector_unmask,
776                                   ivshmem_vector_mask,
777                                   ivshmem_vector_poll)) {
778         error_report("ivshmem: msix_set_vector_notifiers failed");
779         goto undo;
780     }
781     return;
782 
783 undo:
784     while (--i >= 0) {
785         ivshmem_remove_kvm_msi_virq(s, i);
786     }
787 }
788 
789 static void ivshmem_disable_irqfd(IVShmemState *s)
790 {
791     PCIDevice *pdev = PCI_DEVICE(s);
792     int i;
793 
794     if (!pdev->msix_vector_use_notifier) {
795         return;
796     }
797 
798     msix_unset_vector_notifiers(pdev);
799 
800     for (i = 0; i < s->peers[s->vm_id].nb_eventfds; i++) {
801         /*
802          * MSI-X is already disabled here so msix_unset_vector_notifiers()
803          * didn't call our release notifier.  Do it now to keep our masks and
804          * unmasks balanced.
805          */
806         if (s->msi_vectors[i].unmasked) {
807             ivshmem_vector_mask(pdev, i);
808         }
809         ivshmem_remove_kvm_msi_virq(s, i);
810     }
811 
812 }
813 
814 static void ivshmem_write_config(PCIDevice *pdev, uint32_t address,
815                                  uint32_t val, int len)
816 {
817     IVShmemState *s = IVSHMEM_COMMON(pdev);
818     int is_enabled, was_enabled = msix_enabled(pdev);
819 
820     pci_default_write_config(pdev, address, val, len);
821     is_enabled = msix_enabled(pdev);
822 
823     if (kvm_msi_via_irqfd_enabled()) {
824         if (!was_enabled && is_enabled) {
825             ivshmem_enable_irqfd(s);
826         } else if (was_enabled && !is_enabled) {
827             ivshmem_disable_irqfd(s);
828         }
829     }
830 }
831 
832 static void ivshmem_common_realize(PCIDevice *dev, Error **errp)
833 {
834     IVShmemState *s = IVSHMEM_COMMON(dev);
835     Error *err = NULL;
836     uint8_t *pci_conf;
837 
838     /* IRQFD requires MSI */
839     if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD) &&
840         !ivshmem_has_feature(s, IVSHMEM_MSI)) {
841         error_setg(errp, "ioeventfd/irqfd requires MSI");
842         return;
843     }
844 
845     pci_conf = dev->config;
846     pci_conf[PCI_COMMAND] = PCI_COMMAND_IO | PCI_COMMAND_MEMORY;
847 
848     memory_region_init_io(&s->ivshmem_mmio, OBJECT(s), &ivshmem_mmio_ops, s,
849                           "ivshmem-mmio", IVSHMEM_REG_BAR_SIZE);
850 
851     /* region for registers*/
852     pci_register_bar(dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY,
853                      &s->ivshmem_mmio);
854 
855     if (s->hostmem != NULL) {
856         IVSHMEM_DPRINTF("using hostmem\n");
857 
858         s->ivshmem_bar2 = host_memory_backend_get_memory(s->hostmem);
859         host_memory_backend_set_mapped(s->hostmem, true);
860     } else {
861         Chardev *chr = qemu_chr_fe_get_driver(&s->server_chr);
862         assert(chr);
863 
864         IVSHMEM_DPRINTF("using shared memory server (socket = %s)\n",
865                         chr->filename);
866 
867         /* we allocate enough space for 16 peers and grow as needed */
868         resize_peers(s, 16);
869 
870         /*
871          * Receive setup messages from server synchronously.
872          * Older versions did it asynchronously, but that creates a
873          * number of entertaining race conditions.
874          */
875         ivshmem_recv_setup(s, &err);
876         if (err) {
877             error_propagate(errp, err);
878             return;
879         }
880 
881         if (s->master == ON_OFF_AUTO_ON && s->vm_id != 0) {
882             error_setg(errp,
883                        "master must connect to the server before any peers");
884             return;
885         }
886 
887         qemu_chr_fe_set_handlers(&s->server_chr, ivshmem_can_receive,
888                                  ivshmem_read, NULL, NULL, s, NULL, true);
889 
890         if (ivshmem_setup_interrupts(s, errp) < 0) {
891             error_prepend(errp, "Failed to initialize interrupts: ");
892             return;
893         }
894     }
895 
896     if (s->master == ON_OFF_AUTO_AUTO) {
897         s->master = s->vm_id == 0 ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
898     }
899 
900     if (!ivshmem_is_master(s)) {
901         error_setg(&s->migration_blocker,
902                    "Migration is disabled when using feature 'peer mode' in device 'ivshmem'");
903         if (migrate_add_blocker(s->migration_blocker, errp) < 0) {
904             error_free(s->migration_blocker);
905             return;
906         }
907     }
908 
909     vmstate_register_ram(s->ivshmem_bar2, DEVICE(s));
910     pci_register_bar(PCI_DEVICE(s), 2,
911                      PCI_BASE_ADDRESS_SPACE_MEMORY |
912                      PCI_BASE_ADDRESS_MEM_PREFETCH |
913                      PCI_BASE_ADDRESS_MEM_TYPE_64,
914                      s->ivshmem_bar2);
915 }
916 
917 static void ivshmem_exit(PCIDevice *dev)
918 {
919     IVShmemState *s = IVSHMEM_COMMON(dev);
920     int i;
921 
922     if (s->migration_blocker) {
923         migrate_del_blocker(s->migration_blocker);
924         error_free(s->migration_blocker);
925     }
926 
927     if (memory_region_is_mapped(s->ivshmem_bar2)) {
928         if (!s->hostmem) {
929             void *addr = memory_region_get_ram_ptr(s->ivshmem_bar2);
930             int fd;
931 
932             if (munmap(addr, memory_region_size(s->ivshmem_bar2) == -1)) {
933                 error_report("Failed to munmap shared memory %s",
934                              strerror(errno));
935             }
936 
937             fd = memory_region_get_fd(s->ivshmem_bar2);
938             close(fd);
939         }
940 
941         vmstate_unregister_ram(s->ivshmem_bar2, DEVICE(dev));
942     }
943 
944     if (s->hostmem) {
945         host_memory_backend_set_mapped(s->hostmem, false);
946     }
947 
948     if (s->peers) {
949         for (i = 0; i < s->nb_peers; i++) {
950             close_peer_eventfds(s, i);
951         }
952         g_free(s->peers);
953     }
954 
955     if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
956         msix_uninit_exclusive_bar(dev);
957     }
958 
959     g_free(s->msi_vectors);
960 }
961 
962 static int ivshmem_pre_load(void *opaque)
963 {
964     IVShmemState *s = opaque;
965 
966     if (!ivshmem_is_master(s)) {
967         error_report("'peer' devices are not migratable");
968         return -EINVAL;
969     }
970 
971     return 0;
972 }
973 
974 static int ivshmem_post_load(void *opaque, int version_id)
975 {
976     IVShmemState *s = opaque;
977 
978     if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
979         ivshmem_msix_vector_use(s);
980     }
981     return 0;
982 }
983 
984 static void ivshmem_common_class_init(ObjectClass *klass, void *data)
985 {
986     DeviceClass *dc = DEVICE_CLASS(klass);
987     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
988 
989     k->realize = ivshmem_common_realize;
990     k->exit = ivshmem_exit;
991     k->config_write = ivshmem_write_config;
992     k->vendor_id = PCI_VENDOR_ID_IVSHMEM;
993     k->device_id = PCI_DEVICE_ID_IVSHMEM;
994     k->class_id = PCI_CLASS_MEMORY_RAM;
995     k->revision = 1;
996     dc->reset = ivshmem_reset;
997     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
998     dc->desc = "Inter-VM shared memory";
999 }
1000 
1001 static const TypeInfo ivshmem_common_info = {
1002     .name          = TYPE_IVSHMEM_COMMON,
1003     .parent        = TYPE_PCI_DEVICE,
1004     .instance_size = sizeof(IVShmemState),
1005     .abstract      = true,
1006     .class_init    = ivshmem_common_class_init,
1007     .interfaces = (InterfaceInfo[]) {
1008         { INTERFACE_CONVENTIONAL_PCI_DEVICE },
1009         { },
1010     },
1011 };
1012 
1013 static const VMStateDescription ivshmem_plain_vmsd = {
1014     .name = TYPE_IVSHMEM_PLAIN,
1015     .version_id = 0,
1016     .minimum_version_id = 0,
1017     .pre_load = ivshmem_pre_load,
1018     .post_load = ivshmem_post_load,
1019     .fields = (VMStateField[]) {
1020         VMSTATE_PCI_DEVICE(parent_obj, IVShmemState),
1021         VMSTATE_UINT32(intrstatus, IVShmemState),
1022         VMSTATE_UINT32(intrmask, IVShmemState),
1023         VMSTATE_END_OF_LIST()
1024     },
1025 };
1026 
1027 static Property ivshmem_plain_properties[] = {
1028     DEFINE_PROP_ON_OFF_AUTO("master", IVShmemState, master, ON_OFF_AUTO_OFF),
1029     DEFINE_PROP_LINK("memdev", IVShmemState, hostmem, TYPE_MEMORY_BACKEND,
1030                      HostMemoryBackend *),
1031     DEFINE_PROP_END_OF_LIST(),
1032 };
1033 
1034 static void ivshmem_plain_realize(PCIDevice *dev, Error **errp)
1035 {
1036     IVShmemState *s = IVSHMEM_COMMON(dev);
1037 
1038     if (!s->hostmem) {
1039         error_setg(errp, "You must specify a 'memdev'");
1040         return;
1041     } else if (host_memory_backend_is_mapped(s->hostmem)) {
1042         error_setg(errp, "can't use already busy memdev: %s",
1043                    object_get_canonical_path_component(OBJECT(s->hostmem)));
1044         return;
1045     }
1046 
1047     ivshmem_common_realize(dev, errp);
1048 }
1049 
1050 static void ivshmem_plain_class_init(ObjectClass *klass, void *data)
1051 {
1052     DeviceClass *dc = DEVICE_CLASS(klass);
1053     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
1054 
1055     k->realize = ivshmem_plain_realize;
1056     device_class_set_props(dc, ivshmem_plain_properties);
1057     dc->vmsd = &ivshmem_plain_vmsd;
1058 }
1059 
1060 static const TypeInfo ivshmem_plain_info = {
1061     .name          = TYPE_IVSHMEM_PLAIN,
1062     .parent        = TYPE_IVSHMEM_COMMON,
1063     .instance_size = sizeof(IVShmemState),
1064     .class_init    = ivshmem_plain_class_init,
1065 };
1066 
1067 static const VMStateDescription ivshmem_doorbell_vmsd = {
1068     .name = TYPE_IVSHMEM_DOORBELL,
1069     .version_id = 0,
1070     .minimum_version_id = 0,
1071     .pre_load = ivshmem_pre_load,
1072     .post_load = ivshmem_post_load,
1073     .fields = (VMStateField[]) {
1074         VMSTATE_PCI_DEVICE(parent_obj, IVShmemState),
1075         VMSTATE_MSIX(parent_obj, IVShmemState),
1076         VMSTATE_UINT32(intrstatus, IVShmemState),
1077         VMSTATE_UINT32(intrmask, IVShmemState),
1078         VMSTATE_END_OF_LIST()
1079     },
1080 };
1081 
1082 static Property ivshmem_doorbell_properties[] = {
1083     DEFINE_PROP_CHR("chardev", IVShmemState, server_chr),
1084     DEFINE_PROP_UINT32("vectors", IVShmemState, vectors, 1),
1085     DEFINE_PROP_BIT("ioeventfd", IVShmemState, features, IVSHMEM_IOEVENTFD,
1086                     true),
1087     DEFINE_PROP_ON_OFF_AUTO("master", IVShmemState, master, ON_OFF_AUTO_OFF),
1088     DEFINE_PROP_END_OF_LIST(),
1089 };
1090 
1091 static void ivshmem_doorbell_init(Object *obj)
1092 {
1093     IVShmemState *s = IVSHMEM_DOORBELL(obj);
1094 
1095     s->features |= (1 << IVSHMEM_MSI);
1096 }
1097 
1098 static void ivshmem_doorbell_realize(PCIDevice *dev, Error **errp)
1099 {
1100     IVShmemState *s = IVSHMEM_COMMON(dev);
1101 
1102     if (!qemu_chr_fe_backend_connected(&s->server_chr)) {
1103         error_setg(errp, "You must specify a 'chardev'");
1104         return;
1105     }
1106 
1107     ivshmem_common_realize(dev, errp);
1108 }
1109 
1110 static void ivshmem_doorbell_class_init(ObjectClass *klass, void *data)
1111 {
1112     DeviceClass *dc = DEVICE_CLASS(klass);
1113     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
1114 
1115     k->realize = ivshmem_doorbell_realize;
1116     device_class_set_props(dc, ivshmem_doorbell_properties);
1117     dc->vmsd = &ivshmem_doorbell_vmsd;
1118 }
1119 
1120 static const TypeInfo ivshmem_doorbell_info = {
1121     .name          = TYPE_IVSHMEM_DOORBELL,
1122     .parent        = TYPE_IVSHMEM_COMMON,
1123     .instance_size = sizeof(IVShmemState),
1124     .instance_init = ivshmem_doorbell_init,
1125     .class_init    = ivshmem_doorbell_class_init,
1126 };
1127 
1128 static void ivshmem_register_types(void)
1129 {
1130     type_register_static(&ivshmem_common_info);
1131     type_register_static(&ivshmem_plain_info);
1132     type_register_static(&ivshmem_doorbell_info);
1133 }
1134 
1135 type_init(ivshmem_register_types)
1136