xref: /openbmc/qemu/hw/misc/ivshmem.c (revision 9121d02c)
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 #include "hw/hw.h"
20 #include "hw/i386/pc.h"
21 #include "hw/pci/pci.h"
22 #include "hw/pci/msix.h"
23 #include "sysemu/kvm.h"
24 #include "migration/migration.h"
25 #include "qapi/qmp/qerror.h"
26 #include "qemu/event_notifier.h"
27 #include "sysemu/char.h"
28 
29 #include <sys/mman.h>
30 #include <sys/types.h>
31 
32 #define PCI_VENDOR_ID_IVSHMEM   PCI_VENDOR_ID_REDHAT_QUMRANET
33 #define PCI_DEVICE_ID_IVSHMEM   0x1110
34 
35 #define IVSHMEM_IOEVENTFD   0
36 #define IVSHMEM_MSI     1
37 
38 #define IVSHMEM_PEER    0
39 #define IVSHMEM_MASTER  1
40 
41 #define IVSHMEM_REG_BAR_SIZE 0x100
42 
43 //#define DEBUG_IVSHMEM
44 #ifdef DEBUG_IVSHMEM
45 #define IVSHMEM_DPRINTF(fmt, ...)        \
46     do {printf("IVSHMEM: " fmt, ## __VA_ARGS__); } while (0)
47 #else
48 #define IVSHMEM_DPRINTF(fmt, ...)
49 #endif
50 
51 typedef struct Peer {
52     int nb_eventfds;
53     EventNotifier *eventfds;
54 } Peer;
55 
56 typedef struct EventfdEntry {
57     PCIDevice *pdev;
58     int vector;
59 } EventfdEntry;
60 
61 typedef struct IVShmemState {
62     PCIDevice dev;
63     uint32_t intrmask;
64     uint32_t intrstatus;
65     uint32_t doorbell;
66 
67     CharDriverState **eventfd_chr;
68     CharDriverState *server_chr;
69     MemoryRegion ivshmem_mmio;
70 
71     /* We might need to register the BAR before we actually have the memory.
72      * So prepare a container MemoryRegion for the BAR immediately and
73      * add a subregion when we have the memory.
74      */
75     MemoryRegion bar;
76     MemoryRegion ivshmem;
77     uint64_t ivshmem_size; /* size of shared memory region */
78     uint32_t ivshmem_attr;
79     uint32_t ivshmem_64bit;
80     int shm_fd; /* shared memory file descriptor */
81 
82     Peer *peers;
83     int nb_peers; /* how many guests we have space for */
84     int max_peer; /* maximum numbered peer */
85 
86     int vm_id;
87     uint32_t vectors;
88     uint32_t features;
89     EventfdEntry *eventfd_table;
90 
91     Error *migration_blocker;
92 
93     char * shmobj;
94     char * sizearg;
95     char * role;
96     int role_val;   /* scalar to avoid multiple string comparisons */
97 } IVShmemState;
98 
99 /* registers for the Inter-VM shared memory device */
100 enum ivshmem_registers {
101     INTRMASK = 0,
102     INTRSTATUS = 4,
103     IVPOSITION = 8,
104     DOORBELL = 12,
105 };
106 
107 static inline uint32_t ivshmem_has_feature(IVShmemState *ivs,
108                                                     unsigned int feature) {
109     return (ivs->features & (1 << feature));
110 }
111 
112 static inline bool is_power_of_two(uint64_t x) {
113     return (x & (x - 1)) == 0;
114 }
115 
116 /* accessing registers - based on rtl8139 */
117 static void ivshmem_update_irq(IVShmemState *s, int val)
118 {
119     int isr;
120     isr = (s->intrstatus & s->intrmask) & 0xffffffff;
121 
122     /* don't print ISR resets */
123     if (isr) {
124         IVSHMEM_DPRINTF("Set IRQ to %d (%04x %04x)\n",
125            isr ? 1 : 0, s->intrstatus, s->intrmask);
126     }
127 
128     qemu_set_irq(s->dev.irq[0], (isr != 0));
129 }
130 
131 static void ivshmem_IntrMask_write(IVShmemState *s, uint32_t val)
132 {
133     IVSHMEM_DPRINTF("IntrMask write(w) val = 0x%04x\n", val);
134 
135     s->intrmask = val;
136 
137     ivshmem_update_irq(s, val);
138 }
139 
140 static uint32_t ivshmem_IntrMask_read(IVShmemState *s)
141 {
142     uint32_t ret = s->intrmask;
143 
144     IVSHMEM_DPRINTF("intrmask read(w) val = 0x%04x\n", ret);
145 
146     return ret;
147 }
148 
149 static void ivshmem_IntrStatus_write(IVShmemState *s, uint32_t val)
150 {
151     IVSHMEM_DPRINTF("IntrStatus write(w) val = 0x%04x\n", val);
152 
153     s->intrstatus = val;
154 
155     ivshmem_update_irq(s, val);
156 }
157 
158 static uint32_t ivshmem_IntrStatus_read(IVShmemState *s)
159 {
160     uint32_t ret = s->intrstatus;
161 
162     /* reading ISR clears all interrupts */
163     s->intrstatus = 0;
164 
165     ivshmem_update_irq(s, 0);
166 
167     return ret;
168 }
169 
170 static void ivshmem_io_write(void *opaque, hwaddr addr,
171                              uint64_t val, unsigned size)
172 {
173     IVShmemState *s = opaque;
174 
175     uint16_t dest = val >> 16;
176     uint16_t vector = val & 0xff;
177 
178     addr &= 0xfc;
179 
180     IVSHMEM_DPRINTF("writing to addr " TARGET_FMT_plx "\n", addr);
181     switch (addr)
182     {
183         case INTRMASK:
184             ivshmem_IntrMask_write(s, val);
185             break;
186 
187         case INTRSTATUS:
188             ivshmem_IntrStatus_write(s, val);
189             break;
190 
191         case DOORBELL:
192             /* check that dest VM ID is reasonable */
193             if (dest > s->max_peer) {
194                 IVSHMEM_DPRINTF("Invalid destination VM ID (%d)\n", dest);
195                 break;
196             }
197 
198             /* check doorbell range */
199             if (vector < s->peers[dest].nb_eventfds) {
200                 IVSHMEM_DPRINTF("Notifying VM %d on vector %d\n", dest, vector);
201                 event_notifier_set(&s->peers[dest].eventfds[vector]);
202             }
203             break;
204         default:
205             IVSHMEM_DPRINTF("Invalid VM Doorbell VM %d\n", dest);
206     }
207 }
208 
209 static uint64_t ivshmem_io_read(void *opaque, hwaddr addr,
210                                 unsigned size)
211 {
212 
213     IVShmemState *s = opaque;
214     uint32_t ret;
215 
216     switch (addr)
217     {
218         case INTRMASK:
219             ret = ivshmem_IntrMask_read(s);
220             break;
221 
222         case INTRSTATUS:
223             ret = ivshmem_IntrStatus_read(s);
224             break;
225 
226         case IVPOSITION:
227             /* return my VM ID if the memory is mapped */
228             if (s->shm_fd > 0) {
229                 ret = s->vm_id;
230             } else {
231                 ret = -1;
232             }
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_receive(void *opaque, const uint8_t *buf, int size)
254 {
255     IVShmemState *s = opaque;
256 
257     ivshmem_IntrStatus_write(s, *buf);
258 
259     IVSHMEM_DPRINTF("ivshmem_receive 0x%02x\n", *buf);
260 }
261 
262 static int ivshmem_can_receive(void * opaque)
263 {
264     return 8;
265 }
266 
267 static void ivshmem_event(void *opaque, int event)
268 {
269     IVSHMEM_DPRINTF("ivshmem_event %d\n", event);
270 }
271 
272 static void fake_irqfd(void *opaque, const uint8_t *buf, int size) {
273 
274     EventfdEntry *entry = opaque;
275     PCIDevice *pdev = entry->pdev;
276 
277     IVSHMEM_DPRINTF("interrupt on vector %p %d\n", pdev, entry->vector);
278     msix_notify(pdev, entry->vector);
279 }
280 
281 static CharDriverState* create_eventfd_chr_device(void * opaque, EventNotifier *n,
282                                                   int vector)
283 {
284     /* create a event character device based on the passed eventfd */
285     IVShmemState *s = opaque;
286     CharDriverState * chr;
287     int eventfd = event_notifier_get_fd(n);
288 
289     chr = qemu_chr_open_eventfd(eventfd);
290 
291     if (chr == NULL) {
292         fprintf(stderr, "creating eventfd for eventfd %d failed\n", eventfd);
293         exit(-1);
294     }
295     qemu_chr_fe_claim_no_fail(chr);
296 
297     /* if MSI is supported we need multiple interrupts */
298     if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
299         s->eventfd_table[vector].pdev = &s->dev;
300         s->eventfd_table[vector].vector = vector;
301 
302         qemu_chr_add_handlers(chr, ivshmem_can_receive, fake_irqfd,
303                       ivshmem_event, &s->eventfd_table[vector]);
304     } else {
305         qemu_chr_add_handlers(chr, ivshmem_can_receive, ivshmem_receive,
306                       ivshmem_event, s);
307     }
308 
309     return chr;
310 
311 }
312 
313 static int check_shm_size(IVShmemState *s, int fd) {
314     /* check that the guest isn't going to try and map more memory than the
315      * the object has allocated return -1 to indicate error */
316 
317     struct stat buf;
318 
319     fstat(fd, &buf);
320 
321     if (s->ivshmem_size > buf.st_size) {
322         fprintf(stderr,
323                 "IVSHMEM ERROR: Requested memory size greater"
324                 " than shared object size (%" PRIu64 " > %" PRIu64")\n",
325                 s->ivshmem_size, (uint64_t)buf.st_size);
326         return -1;
327     } else {
328         return 0;
329     }
330 }
331 
332 /* create the shared memory BAR when we are not using the server, so we can
333  * create the BAR and map the memory immediately */
334 static void create_shared_memory_BAR(IVShmemState *s, int fd) {
335 
336     void * ptr;
337 
338     s->shm_fd = fd;
339 
340     ptr = mmap(0, s->ivshmem_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
341 
342     memory_region_init_ram_ptr(&s->ivshmem, OBJECT(s), "ivshmem.bar2",
343                                s->ivshmem_size, ptr);
344     vmstate_register_ram(&s->ivshmem, &s->dev.qdev);
345     memory_region_add_subregion(&s->bar, 0, &s->ivshmem);
346 
347     /* region for shared memory */
348     pci_register_bar(&s->dev, 2, s->ivshmem_attr, &s->bar);
349 }
350 
351 static void ivshmem_add_eventfd(IVShmemState *s, int posn, int i)
352 {
353     memory_region_add_eventfd(&s->ivshmem_mmio,
354                               DOORBELL,
355                               4,
356                               true,
357                               (posn << 16) | i,
358                               &s->peers[posn].eventfds[i]);
359 }
360 
361 static void ivshmem_del_eventfd(IVShmemState *s, int posn, int i)
362 {
363     memory_region_del_eventfd(&s->ivshmem_mmio,
364                               DOORBELL,
365                               4,
366                               true,
367                               (posn << 16) | i,
368                               &s->peers[posn].eventfds[i]);
369 }
370 
371 static void close_guest_eventfds(IVShmemState *s, int posn)
372 {
373     int i, guest_curr_max;
374 
375     if (!ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) {
376         return;
377     }
378 
379     guest_curr_max = s->peers[posn].nb_eventfds;
380 
381     memory_region_transaction_begin();
382     for (i = 0; i < guest_curr_max; i++) {
383         ivshmem_del_eventfd(s, posn, i);
384     }
385     memory_region_transaction_commit();
386     for (i = 0; i < guest_curr_max; i++) {
387         event_notifier_cleanup(&s->peers[posn].eventfds[i]);
388     }
389 
390     g_free(s->peers[posn].eventfds);
391     s->peers[posn].nb_eventfds = 0;
392 }
393 
394 /* this function increase the dynamic storage need to store data about other
395  * guests */
396 static void increase_dynamic_storage(IVShmemState *s, int new_min_size) {
397 
398     int j, old_nb_alloc;
399 
400     old_nb_alloc = s->nb_peers;
401 
402     while (new_min_size >= s->nb_peers)
403         s->nb_peers = s->nb_peers * 2;
404 
405     IVSHMEM_DPRINTF("bumping storage to %d guests\n", s->nb_peers);
406     s->peers = g_realloc(s->peers, s->nb_peers * sizeof(Peer));
407 
408     /* zero out new pointers */
409     for (j = old_nb_alloc; j < s->nb_peers; j++) {
410         s->peers[j].eventfds = NULL;
411         s->peers[j].nb_eventfds = 0;
412     }
413 }
414 
415 static void ivshmem_read(void *opaque, const uint8_t * buf, int flags)
416 {
417     IVShmemState *s = opaque;
418     int incoming_fd, tmp_fd;
419     int guest_max_eventfd;
420     long incoming_posn;
421 
422     memcpy(&incoming_posn, buf, sizeof(long));
423     /* pick off s->server_chr->msgfd and store it, posn should accompany msg */
424     tmp_fd = qemu_chr_fe_get_msgfd(s->server_chr);
425     IVSHMEM_DPRINTF("posn is %ld, fd is %d\n", incoming_posn, tmp_fd);
426 
427     /* make sure we have enough space for this guest */
428     if (incoming_posn >= s->nb_peers) {
429         increase_dynamic_storage(s, incoming_posn);
430     }
431 
432     if (tmp_fd == -1) {
433         /* if posn is positive and unseen before then this is our posn*/
434         if ((incoming_posn >= 0) &&
435                             (s->peers[incoming_posn].eventfds == NULL)) {
436             /* receive our posn */
437             s->vm_id = incoming_posn;
438             return;
439         } else {
440             /* otherwise an fd == -1 means an existing guest has gone away */
441             IVSHMEM_DPRINTF("posn %ld has gone away\n", incoming_posn);
442             close_guest_eventfds(s, incoming_posn);
443             return;
444         }
445     }
446 
447     /* because of the implementation of get_msgfd, we need a dup */
448     incoming_fd = dup(tmp_fd);
449 
450     if (incoming_fd == -1) {
451         fprintf(stderr, "could not allocate file descriptor %s\n",
452                                                             strerror(errno));
453         return;
454     }
455 
456     /* if the position is -1, then it's shared memory region fd */
457     if (incoming_posn == -1) {
458 
459         void * map_ptr;
460 
461         s->max_peer = 0;
462 
463         if (check_shm_size(s, incoming_fd) == -1) {
464             exit(-1);
465         }
466 
467         /* mmap the region and map into the BAR2 */
468         map_ptr = mmap(0, s->ivshmem_size, PROT_READ|PROT_WRITE, MAP_SHARED,
469                                                             incoming_fd, 0);
470         memory_region_init_ram_ptr(&s->ivshmem, OBJECT(s),
471                                    "ivshmem.bar2", s->ivshmem_size, map_ptr);
472         vmstate_register_ram(&s->ivshmem, &s->dev.qdev);
473 
474         IVSHMEM_DPRINTF("guest h/w addr = %" PRIu64 ", size = %" PRIu64 "\n",
475                          s->ivshmem_offset, s->ivshmem_size);
476 
477         memory_region_add_subregion(&s->bar, 0, &s->ivshmem);
478 
479         /* only store the fd if it is successfully mapped */
480         s->shm_fd = incoming_fd;
481 
482         return;
483     }
484 
485     /* each guest has an array of eventfds, and we keep track of how many
486      * guests for each VM */
487     guest_max_eventfd = s->peers[incoming_posn].nb_eventfds;
488 
489     if (guest_max_eventfd == 0) {
490         /* one eventfd per MSI vector */
491         s->peers[incoming_posn].eventfds = g_new(EventNotifier, s->vectors);
492     }
493 
494     /* this is an eventfd for a particular guest VM */
495     IVSHMEM_DPRINTF("eventfds[%ld][%d] = %d\n", incoming_posn,
496                                             guest_max_eventfd, incoming_fd);
497     event_notifier_init_fd(&s->peers[incoming_posn].eventfds[guest_max_eventfd],
498                            incoming_fd);
499 
500     /* increment count for particular guest */
501     s->peers[incoming_posn].nb_eventfds++;
502 
503     /* keep track of the maximum VM ID */
504     if (incoming_posn > s->max_peer) {
505         s->max_peer = incoming_posn;
506     }
507 
508     if (incoming_posn == s->vm_id) {
509         s->eventfd_chr[guest_max_eventfd] = create_eventfd_chr_device(s,
510                    &s->peers[s->vm_id].eventfds[guest_max_eventfd],
511                    guest_max_eventfd);
512     }
513 
514     if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) {
515         ivshmem_add_eventfd(s, incoming_posn, guest_max_eventfd);
516     }
517 }
518 
519 /* Select the MSI-X vectors used by device.
520  * ivshmem maps events to vectors statically, so
521  * we just enable all vectors on init and after reset. */
522 static void ivshmem_use_msix(IVShmemState * s)
523 {
524     int i;
525 
526     if (!msix_present(&s->dev)) {
527         return;
528     }
529 
530     for (i = 0; i < s->vectors; i++) {
531         msix_vector_use(&s->dev, i);
532     }
533 }
534 
535 static void ivshmem_reset(DeviceState *d)
536 {
537     IVShmemState *s = DO_UPCAST(IVShmemState, dev.qdev, d);
538 
539     s->intrstatus = 0;
540     ivshmem_use_msix(s);
541 }
542 
543 static uint64_t ivshmem_get_size(IVShmemState * s) {
544 
545     uint64_t value;
546     char *ptr;
547 
548     value = strtoull(s->sizearg, &ptr, 10);
549     switch (*ptr) {
550         case 0: case 'M': case 'm':
551             value <<= 20;
552             break;
553         case 'G': case 'g':
554             value <<= 30;
555             break;
556         default:
557             fprintf(stderr, "qemu: invalid ram size: %s\n", s->sizearg);
558             exit(1);
559     }
560 
561     /* BARs must be a power of 2 */
562     if (!is_power_of_two(value)) {
563         fprintf(stderr, "ivshmem: size must be power of 2\n");
564         exit(1);
565     }
566 
567     return value;
568 }
569 
570 static void ivshmem_setup_msi(IVShmemState * s)
571 {
572     if (msix_init_exclusive_bar(&s->dev, s->vectors, 1)) {
573         IVSHMEM_DPRINTF("msix initialization failed\n");
574         exit(1);
575     }
576 
577     IVSHMEM_DPRINTF("msix initialized (%d vectors)\n", s->vectors);
578 
579     /* allocate QEMU char devices for receiving interrupts */
580     s->eventfd_table = g_malloc0(s->vectors * sizeof(EventfdEntry));
581 
582     ivshmem_use_msix(s);
583 }
584 
585 static void ivshmem_save(QEMUFile* f, void *opaque)
586 {
587     IVShmemState *proxy = opaque;
588 
589     IVSHMEM_DPRINTF("ivshmem_save\n");
590     pci_device_save(&proxy->dev, f);
591 
592     if (ivshmem_has_feature(proxy, IVSHMEM_MSI)) {
593         msix_save(&proxy->dev, f);
594     } else {
595         qemu_put_be32(f, proxy->intrstatus);
596         qemu_put_be32(f, proxy->intrmask);
597     }
598 
599 }
600 
601 static int ivshmem_load(QEMUFile* f, void *opaque, int version_id)
602 {
603     IVSHMEM_DPRINTF("ivshmem_load\n");
604 
605     IVShmemState *proxy = opaque;
606     int ret;
607 
608     if (version_id > 0) {
609         return -EINVAL;
610     }
611 
612     if (proxy->role_val == IVSHMEM_PEER) {
613         fprintf(stderr, "ivshmem: 'peer' devices are not migratable\n");
614         return -EINVAL;
615     }
616 
617     ret = pci_device_load(&proxy->dev, f);
618     if (ret) {
619         return ret;
620     }
621 
622     if (ivshmem_has_feature(proxy, IVSHMEM_MSI)) {
623         msix_load(&proxy->dev, f);
624 	ivshmem_use_msix(proxy);
625     } else {
626         proxy->intrstatus = qemu_get_be32(f);
627         proxy->intrmask = qemu_get_be32(f);
628     }
629 
630     return 0;
631 }
632 
633 static void ivshmem_write_config(PCIDevice *pci_dev, uint32_t address,
634 				 uint32_t val, int len)
635 {
636     pci_default_write_config(pci_dev, address, val, len);
637     msix_write_config(pci_dev, address, val, len);
638 }
639 
640 static int pci_ivshmem_init(PCIDevice *dev)
641 {
642     IVShmemState *s = DO_UPCAST(IVShmemState, dev, dev);
643     uint8_t *pci_conf;
644 
645     if (s->sizearg == NULL)
646         s->ivshmem_size = 4 << 20; /* 4 MB default */
647     else {
648         s->ivshmem_size = ivshmem_get_size(s);
649     }
650 
651     register_savevm(&s->dev.qdev, "ivshmem", 0, 0, ivshmem_save, ivshmem_load,
652                                                                         dev);
653 
654     /* IRQFD requires MSI */
655     if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD) &&
656         !ivshmem_has_feature(s, IVSHMEM_MSI)) {
657         fprintf(stderr, "ivshmem: ioeventfd/irqfd requires MSI\n");
658         exit(1);
659     }
660 
661     /* check that role is reasonable */
662     if (s->role) {
663         if (strncmp(s->role, "peer", 5) == 0) {
664             s->role_val = IVSHMEM_PEER;
665         } else if (strncmp(s->role, "master", 7) == 0) {
666             s->role_val = IVSHMEM_MASTER;
667         } else {
668             fprintf(stderr, "ivshmem: 'role' must be 'peer' or 'master'\n");
669             exit(1);
670         }
671     } else {
672         s->role_val = IVSHMEM_MASTER; /* default */
673     }
674 
675     if (s->role_val == IVSHMEM_PEER) {
676         error_set(&s->migration_blocker, QERR_DEVICE_FEATURE_BLOCKS_MIGRATION,
677                   "peer mode", "ivshmem");
678         migrate_add_blocker(s->migration_blocker);
679     }
680 
681     pci_conf = s->dev.config;
682     pci_conf[PCI_COMMAND] = PCI_COMMAND_IO | PCI_COMMAND_MEMORY;
683 
684     pci_config_set_interrupt_pin(pci_conf, 1);
685 
686     s->shm_fd = 0;
687 
688     memory_region_init_io(&s->ivshmem_mmio, OBJECT(s), &ivshmem_mmio_ops, s,
689                           "ivshmem-mmio", IVSHMEM_REG_BAR_SIZE);
690 
691     /* region for registers*/
692     pci_register_bar(&s->dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY,
693                      &s->ivshmem_mmio);
694 
695     memory_region_init(&s->bar, OBJECT(s), "ivshmem-bar2-container", s->ivshmem_size);
696     s->ivshmem_attr = PCI_BASE_ADDRESS_SPACE_MEMORY |
697         PCI_BASE_ADDRESS_MEM_PREFETCH;
698     if (s->ivshmem_64bit) {
699         s->ivshmem_attr |= PCI_BASE_ADDRESS_MEM_TYPE_64;
700     }
701 
702     if ((s->server_chr != NULL) &&
703                         (strncmp(s->server_chr->filename, "unix:", 5) == 0)) {
704         /* if we get a UNIX socket as the parameter we will talk
705          * to the ivshmem server to receive the memory region */
706 
707         if (s->shmobj != NULL) {
708             fprintf(stderr, "WARNING: do not specify both 'chardev' "
709                                                 "and 'shm' with ivshmem\n");
710         }
711 
712         IVSHMEM_DPRINTF("using shared memory server (socket = %s)\n",
713                                                     s->server_chr->filename);
714 
715         if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
716             ivshmem_setup_msi(s);
717         }
718 
719         /* we allocate enough space for 16 guests and grow as needed */
720         s->nb_peers = 16;
721         s->vm_id = -1;
722 
723         /* allocate/initialize space for interrupt handling */
724         s->peers = g_malloc0(s->nb_peers * sizeof(Peer));
725 
726         pci_register_bar(&s->dev, 2, s->ivshmem_attr, &s->bar);
727 
728         s->eventfd_chr = g_malloc0(s->vectors * sizeof(CharDriverState *));
729 
730         qemu_chr_add_handlers(s->server_chr, ivshmem_can_receive, ivshmem_read,
731                      ivshmem_event, s);
732     } else {
733         /* just map the file immediately, we're not using a server */
734         int fd;
735 
736         if (s->shmobj == NULL) {
737             fprintf(stderr, "Must specify 'chardev' or 'shm' to ivshmem\n");
738             exit(1);
739         }
740 
741         IVSHMEM_DPRINTF("using shm_open (shm object = %s)\n", s->shmobj);
742 
743         /* try opening with O_EXCL and if it succeeds zero the memory
744          * by truncating to 0 */
745         if ((fd = shm_open(s->shmobj, O_CREAT|O_RDWR|O_EXCL,
746                         S_IRWXU|S_IRWXG|S_IRWXO)) > 0) {
747            /* truncate file to length PCI device's memory */
748             if (ftruncate(fd, s->ivshmem_size) != 0) {
749                 fprintf(stderr, "ivshmem: could not truncate shared file\n");
750             }
751 
752         } else if ((fd = shm_open(s->shmobj, O_CREAT|O_RDWR,
753                         S_IRWXU|S_IRWXG|S_IRWXO)) < 0) {
754             fprintf(stderr, "ivshmem: could not open shared file\n");
755             exit(-1);
756 
757         }
758 
759         if (check_shm_size(s, fd) == -1) {
760             exit(-1);
761         }
762 
763         create_shared_memory_BAR(s, fd);
764 
765     }
766 
767     s->dev.config_write = ivshmem_write_config;
768 
769     return 0;
770 }
771 
772 static void pci_ivshmem_uninit(PCIDevice *dev)
773 {
774     IVShmemState *s = DO_UPCAST(IVShmemState, dev, dev);
775 
776     if (s->migration_blocker) {
777         migrate_del_blocker(s->migration_blocker);
778         error_free(s->migration_blocker);
779     }
780 
781     memory_region_destroy(&s->ivshmem_mmio);
782     memory_region_del_subregion(&s->bar, &s->ivshmem);
783     vmstate_unregister_ram(&s->ivshmem, &s->dev.qdev);
784     memory_region_destroy(&s->ivshmem);
785     memory_region_destroy(&s->bar);
786     unregister_savevm(&dev->qdev, "ivshmem", s);
787 }
788 
789 static Property ivshmem_properties[] = {
790     DEFINE_PROP_CHR("chardev", IVShmemState, server_chr),
791     DEFINE_PROP_STRING("size", IVShmemState, sizearg),
792     DEFINE_PROP_UINT32("vectors", IVShmemState, vectors, 1),
793     DEFINE_PROP_BIT("ioeventfd", IVShmemState, features, IVSHMEM_IOEVENTFD, false),
794     DEFINE_PROP_BIT("msi", IVShmemState, features, IVSHMEM_MSI, true),
795     DEFINE_PROP_STRING("shm", IVShmemState, shmobj),
796     DEFINE_PROP_STRING("role", IVShmemState, role),
797     DEFINE_PROP_UINT32("use64", IVShmemState, ivshmem_64bit, 1),
798     DEFINE_PROP_END_OF_LIST(),
799 };
800 
801 static void ivshmem_class_init(ObjectClass *klass, void *data)
802 {
803     DeviceClass *dc = DEVICE_CLASS(klass);
804     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
805 
806     k->init = pci_ivshmem_init;
807     k->exit = pci_ivshmem_uninit;
808     k->vendor_id = PCI_VENDOR_ID_IVSHMEM;
809     k->device_id = PCI_DEVICE_ID_IVSHMEM;
810     k->class_id = PCI_CLASS_MEMORY_RAM;
811     dc->reset = ivshmem_reset;
812     dc->props = ivshmem_properties;
813 }
814 
815 static const TypeInfo ivshmem_info = {
816     .name          = "ivshmem",
817     .parent        = TYPE_PCI_DEVICE,
818     .instance_size = sizeof(IVShmemState),
819     .class_init    = ivshmem_class_init,
820 };
821 
822 static void ivshmem_register_types(void)
823 {
824     type_register_static(&ivshmem_info);
825 }
826 
827 type_init(ivshmem_register_types)
828