xref: /openbmc/qemu/hw/virtio/virtio-mem.c (revision 30b6852c)
1 /*
2  * Virtio MEM device
3  *
4  * Copyright (C) 2020 Red Hat, Inc.
5  *
6  * Authors:
7  *  David Hildenbrand <david@redhat.com>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2.
10  * See the COPYING file in the top-level directory.
11  */
12 
13 #include "qemu/osdep.h"
14 #include "qemu-common.h"
15 #include "qemu/iov.h"
16 #include "qemu/cutils.h"
17 #include "qemu/error-report.h"
18 #include "qemu/units.h"
19 #include "sysemu/numa.h"
20 #include "sysemu/sysemu.h"
21 #include "sysemu/reset.h"
22 #include "hw/virtio/virtio.h"
23 #include "hw/virtio/virtio-bus.h"
24 #include "hw/virtio/virtio-access.h"
25 #include "hw/virtio/virtio-mem.h"
26 #include "qapi/error.h"
27 #include "qapi/visitor.h"
28 #include "exec/ram_addr.h"
29 #include "migration/misc.h"
30 #include "hw/boards.h"
31 #include "hw/qdev-properties.h"
32 #include CONFIG_DEVICES
33 #include "trace.h"
34 
35 /*
36  * Let's not allow blocks smaller than 1 MiB, for example, to keep the tracking
37  * bitmap small.
38  */
39 #define VIRTIO_MEM_MIN_BLOCK_SIZE ((uint32_t)(1 * MiB))
40 
41 #if defined(__x86_64__) || defined(__arm__) || defined(__aarch64__) || \
42     defined(__powerpc64__)
43 #define VIRTIO_MEM_DEFAULT_THP_SIZE ((uint32_t)(2 * MiB))
44 #else
45         /* fallback to 1 MiB (e.g., the THP size on s390x) */
46 #define VIRTIO_MEM_DEFAULT_THP_SIZE VIRTIO_MEM_MIN_BLOCK_SIZE
47 #endif
48 
49 /*
50  * We want to have a reasonable default block size such that
51  * 1. We avoid splitting THPs when unplugging memory, which degrades
52  *    performance.
53  * 2. We avoid placing THPs for plugged blocks that also cover unplugged
54  *    blocks.
55  *
56  * The actual THP size might differ between Linux kernels, so we try to probe
57  * it. In the future (if we ever run into issues regarding 2.), we might want
58  * to disable THP in case we fail to properly probe the THP size, or if the
59  * block size is configured smaller than the THP size.
60  */
61 static uint32_t thp_size;
62 
63 #define HPAGE_PMD_SIZE_PATH "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size"
64 static uint32_t virtio_mem_thp_size(void)
65 {
66     gchar *content = NULL;
67     const char *endptr;
68     uint64_t tmp;
69 
70     if (thp_size) {
71         return thp_size;
72     }
73 
74     /*
75      * Try to probe the actual THP size, fallback to (sane but eventually
76      * incorrect) default sizes.
77      */
78     if (g_file_get_contents(HPAGE_PMD_SIZE_PATH, &content, NULL, NULL) &&
79         !qemu_strtou64(content, &endptr, 0, &tmp) &&
80         (!endptr || *endptr == '\n')) {
81         /*
82          * Sanity-check the value, if it's too big (e.g., aarch64 with 64k base
83          * pages) or weird, fallback to something smaller.
84          */
85         if (!tmp || !is_power_of_2(tmp) || tmp > 16 * MiB) {
86             warn_report("Read unsupported THP size: %" PRIx64, tmp);
87         } else {
88             thp_size = tmp;
89         }
90     }
91 
92     if (!thp_size) {
93         thp_size = VIRTIO_MEM_DEFAULT_THP_SIZE;
94         warn_report("Could not detect THP size, falling back to %" PRIx64
95                     "  MiB.", thp_size / MiB);
96     }
97 
98     g_free(content);
99     return thp_size;
100 }
101 
102 static uint64_t virtio_mem_default_block_size(RAMBlock *rb)
103 {
104     const uint64_t page_size = qemu_ram_pagesize(rb);
105 
106     /* We can have hugetlbfs with a page size smaller than the THP size. */
107     if (page_size == qemu_real_host_page_size) {
108         return MAX(page_size, virtio_mem_thp_size());
109     }
110     return MAX(page_size, VIRTIO_MEM_MIN_BLOCK_SIZE);
111 }
112 
113 /*
114  * Size the usable region bigger than the requested size if possible. Esp.
115  * Linux guests will only add (aligned) memory blocks in case they fully
116  * fit into the usable region, but plug+online only a subset of the pages.
117  * The memory block size corresponds mostly to the section size.
118  *
119  * This allows e.g., to add 20MB with a section size of 128MB on x86_64, and
120  * a section size of 1GB on arm64 (as long as the start address is properly
121  * aligned, similar to ordinary DIMMs).
122  *
123  * We can change this at any time and maybe even make it configurable if
124  * necessary (as the section size can change). But it's more likely that the
125  * section size will rather get smaller and not bigger over time.
126  */
127 #if defined(TARGET_X86_64) || defined(TARGET_I386)
128 #define VIRTIO_MEM_USABLE_EXTENT (2 * (128 * MiB))
129 #else
130 #error VIRTIO_MEM_USABLE_EXTENT not defined
131 #endif
132 
133 static bool virtio_mem_is_busy(void)
134 {
135     /*
136      * Postcopy cannot handle concurrent discards and we don't want to migrate
137      * pages on-demand with stale content when plugging new blocks.
138      *
139      * For precopy, we don't want unplugged blocks in our migration stream, and
140      * when plugging new blocks, the page content might differ between source
141      * and destination (observable by the guest when not initializing pages
142      * after plugging them) until we're running on the destination (as we didn't
143      * migrate these blocks when they were unplugged).
144      */
145     return migration_in_incoming_postcopy() || !migration_is_idle();
146 }
147 
148 typedef int (*virtio_mem_range_cb)(const VirtIOMEM *vmem, void *arg,
149                                    uint64_t offset, uint64_t size);
150 
151 static int virtio_mem_for_each_unplugged_range(const VirtIOMEM *vmem, void *arg,
152                                                virtio_mem_range_cb cb)
153 {
154     unsigned long first_zero_bit, last_zero_bit;
155     uint64_t offset, size;
156     int ret = 0;
157 
158     first_zero_bit = find_first_zero_bit(vmem->bitmap, vmem->bitmap_size);
159     while (first_zero_bit < vmem->bitmap_size) {
160         offset = first_zero_bit * vmem->block_size;
161         last_zero_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size,
162                                       first_zero_bit + 1) - 1;
163         size = (last_zero_bit - first_zero_bit + 1) * vmem->block_size;
164 
165         ret = cb(vmem, arg, offset, size);
166         if (ret) {
167             break;
168         }
169         first_zero_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size,
170                                             last_zero_bit + 2);
171     }
172     return ret;
173 }
174 
175 /*
176  * Adjust the memory section to cover the intersection with the given range.
177  *
178  * Returns false if the intersection is empty, otherwise returns true.
179  */
180 static bool virito_mem_intersect_memory_section(MemoryRegionSection *s,
181                                                 uint64_t offset, uint64_t size)
182 {
183     uint64_t start = MAX(s->offset_within_region, offset);
184     uint64_t end = MIN(s->offset_within_region + int128_get64(s->size),
185                        offset + size);
186 
187     if (end <= start) {
188         return false;
189     }
190 
191     s->offset_within_address_space += start - s->offset_within_region;
192     s->offset_within_region = start;
193     s->size = int128_make64(end - start);
194     return true;
195 }
196 
197 typedef int (*virtio_mem_section_cb)(MemoryRegionSection *s, void *arg);
198 
199 static int virtio_mem_for_each_plugged_section(const VirtIOMEM *vmem,
200                                                MemoryRegionSection *s,
201                                                void *arg,
202                                                virtio_mem_section_cb cb)
203 {
204     unsigned long first_bit, last_bit;
205     uint64_t offset, size;
206     int ret = 0;
207 
208     first_bit = s->offset_within_region / vmem->bitmap_size;
209     first_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size, first_bit);
210     while (first_bit < vmem->bitmap_size) {
211         MemoryRegionSection tmp = *s;
212 
213         offset = first_bit * vmem->block_size;
214         last_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size,
215                                       first_bit + 1) - 1;
216         size = (last_bit - first_bit + 1) * vmem->block_size;
217 
218         if (!virito_mem_intersect_memory_section(&tmp, offset, size)) {
219             break;
220         }
221         ret = cb(&tmp, arg);
222         if (ret) {
223             break;
224         }
225         first_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size,
226                                   last_bit + 2);
227     }
228     return ret;
229 }
230 
231 static int virtio_mem_notify_populate_cb(MemoryRegionSection *s, void *arg)
232 {
233     RamDiscardListener *rdl = arg;
234 
235     return rdl->notify_populate(rdl, s);
236 }
237 
238 static int virtio_mem_notify_discard_cb(MemoryRegionSection *s, void *arg)
239 {
240     RamDiscardListener *rdl = arg;
241 
242     rdl->notify_discard(rdl, s);
243     return 0;
244 }
245 
246 static void virtio_mem_notify_unplug(VirtIOMEM *vmem, uint64_t offset,
247                                      uint64_t size)
248 {
249     RamDiscardListener *rdl;
250 
251     QLIST_FOREACH(rdl, &vmem->rdl_list, next) {
252         MemoryRegionSection tmp = *rdl->section;
253 
254         if (!virito_mem_intersect_memory_section(&tmp, offset, size)) {
255             continue;
256         }
257         rdl->notify_discard(rdl, &tmp);
258     }
259 }
260 
261 static int virtio_mem_notify_plug(VirtIOMEM *vmem, uint64_t offset,
262                                   uint64_t size)
263 {
264     RamDiscardListener *rdl, *rdl2;
265     int ret = 0;
266 
267     QLIST_FOREACH(rdl, &vmem->rdl_list, next) {
268         MemoryRegionSection tmp = *rdl->section;
269 
270         if (!virito_mem_intersect_memory_section(&tmp, offset, size)) {
271             continue;
272         }
273         ret = rdl->notify_populate(rdl, &tmp);
274         if (ret) {
275             break;
276         }
277     }
278 
279     if (ret) {
280         /* Notify all already-notified listeners. */
281         QLIST_FOREACH(rdl2, &vmem->rdl_list, next) {
282             MemoryRegionSection tmp = *rdl->section;
283 
284             if (rdl2 == rdl) {
285                 break;
286             }
287             if (!virito_mem_intersect_memory_section(&tmp, offset, size)) {
288                 continue;
289             }
290             rdl2->notify_discard(rdl2, &tmp);
291         }
292     }
293     return ret;
294 }
295 
296 static void virtio_mem_notify_unplug_all(VirtIOMEM *vmem)
297 {
298     RamDiscardListener *rdl;
299 
300     if (!vmem->size) {
301         return;
302     }
303 
304     QLIST_FOREACH(rdl, &vmem->rdl_list, next) {
305         if (rdl->double_discard_supported) {
306             rdl->notify_discard(rdl, rdl->section);
307         } else {
308             virtio_mem_for_each_plugged_section(vmem, rdl->section, rdl,
309                                                 virtio_mem_notify_discard_cb);
310         }
311     }
312 }
313 
314 static bool virtio_mem_test_bitmap(const VirtIOMEM *vmem, uint64_t start_gpa,
315                                    uint64_t size, bool plugged)
316 {
317     const unsigned long first_bit = (start_gpa - vmem->addr) / vmem->block_size;
318     const unsigned long last_bit = first_bit + (size / vmem->block_size) - 1;
319     unsigned long found_bit;
320 
321     /* We fake a shorter bitmap to avoid searching too far. */
322     if (plugged) {
323         found_bit = find_next_zero_bit(vmem->bitmap, last_bit + 1, first_bit);
324     } else {
325         found_bit = find_next_bit(vmem->bitmap, last_bit + 1, first_bit);
326     }
327     return found_bit > last_bit;
328 }
329 
330 static void virtio_mem_set_bitmap(VirtIOMEM *vmem, uint64_t start_gpa,
331                                   uint64_t size, bool plugged)
332 {
333     const unsigned long bit = (start_gpa - vmem->addr) / vmem->block_size;
334     const unsigned long nbits = size / vmem->block_size;
335 
336     if (plugged) {
337         bitmap_set(vmem->bitmap, bit, nbits);
338     } else {
339         bitmap_clear(vmem->bitmap, bit, nbits);
340     }
341 }
342 
343 static void virtio_mem_send_response(VirtIOMEM *vmem, VirtQueueElement *elem,
344                                      struct virtio_mem_resp *resp)
345 {
346     VirtIODevice *vdev = VIRTIO_DEVICE(vmem);
347     VirtQueue *vq = vmem->vq;
348 
349     trace_virtio_mem_send_response(le16_to_cpu(resp->type));
350     iov_from_buf(elem->in_sg, elem->in_num, 0, resp, sizeof(*resp));
351 
352     virtqueue_push(vq, elem, sizeof(*resp));
353     virtio_notify(vdev, vq);
354 }
355 
356 static void virtio_mem_send_response_simple(VirtIOMEM *vmem,
357                                             VirtQueueElement *elem,
358                                             uint16_t type)
359 {
360     struct virtio_mem_resp resp = {
361         .type = cpu_to_le16(type),
362     };
363 
364     virtio_mem_send_response(vmem, elem, &resp);
365 }
366 
367 static bool virtio_mem_valid_range(const VirtIOMEM *vmem, uint64_t gpa,
368                                    uint64_t size)
369 {
370     if (!QEMU_IS_ALIGNED(gpa, vmem->block_size)) {
371         return false;
372     }
373     if (gpa + size < gpa || !size) {
374         return false;
375     }
376     if (gpa < vmem->addr || gpa >= vmem->addr + vmem->usable_region_size) {
377         return false;
378     }
379     if (gpa + size > vmem->addr + vmem->usable_region_size) {
380         return false;
381     }
382     return true;
383 }
384 
385 static int virtio_mem_set_block_state(VirtIOMEM *vmem, uint64_t start_gpa,
386                                       uint64_t size, bool plug)
387 {
388     const uint64_t offset = start_gpa - vmem->addr;
389     RAMBlock *rb = vmem->memdev->mr.ram_block;
390 
391     if (virtio_mem_is_busy()) {
392         return -EBUSY;
393     }
394 
395     if (!plug) {
396         if (ram_block_discard_range(rb, offset, size)) {
397             return -EBUSY;
398         }
399         virtio_mem_notify_unplug(vmem, offset, size);
400     } else if (virtio_mem_notify_plug(vmem, offset, size)) {
401         /* Could be a mapping attempt resulted in memory getting populated. */
402         ram_block_discard_range(vmem->memdev->mr.ram_block, offset, size);
403         return -EBUSY;
404     }
405     virtio_mem_set_bitmap(vmem, start_gpa, size, plug);
406     return 0;
407 }
408 
409 static int virtio_mem_state_change_request(VirtIOMEM *vmem, uint64_t gpa,
410                                            uint16_t nb_blocks, bool plug)
411 {
412     const uint64_t size = nb_blocks * vmem->block_size;
413     int ret;
414 
415     if (!virtio_mem_valid_range(vmem, gpa, size)) {
416         return VIRTIO_MEM_RESP_ERROR;
417     }
418 
419     if (plug && (vmem->size + size > vmem->requested_size)) {
420         return VIRTIO_MEM_RESP_NACK;
421     }
422 
423     /* test if really all blocks are in the opposite state */
424     if (!virtio_mem_test_bitmap(vmem, gpa, size, !plug)) {
425         return VIRTIO_MEM_RESP_ERROR;
426     }
427 
428     ret = virtio_mem_set_block_state(vmem, gpa, size, plug);
429     if (ret) {
430         return VIRTIO_MEM_RESP_BUSY;
431     }
432     if (plug) {
433         vmem->size += size;
434     } else {
435         vmem->size -= size;
436     }
437     notifier_list_notify(&vmem->size_change_notifiers, &vmem->size);
438     return VIRTIO_MEM_RESP_ACK;
439 }
440 
441 static void virtio_mem_plug_request(VirtIOMEM *vmem, VirtQueueElement *elem,
442                                     struct virtio_mem_req *req)
443 {
444     const uint64_t gpa = le64_to_cpu(req->u.plug.addr);
445     const uint16_t nb_blocks = le16_to_cpu(req->u.plug.nb_blocks);
446     uint16_t type;
447 
448     trace_virtio_mem_plug_request(gpa, nb_blocks);
449     type = virtio_mem_state_change_request(vmem, gpa, nb_blocks, true);
450     virtio_mem_send_response_simple(vmem, elem, type);
451 }
452 
453 static void virtio_mem_unplug_request(VirtIOMEM *vmem, VirtQueueElement *elem,
454                                       struct virtio_mem_req *req)
455 {
456     const uint64_t gpa = le64_to_cpu(req->u.unplug.addr);
457     const uint16_t nb_blocks = le16_to_cpu(req->u.unplug.nb_blocks);
458     uint16_t type;
459 
460     trace_virtio_mem_unplug_request(gpa, nb_blocks);
461     type = virtio_mem_state_change_request(vmem, gpa, nb_blocks, false);
462     virtio_mem_send_response_simple(vmem, elem, type);
463 }
464 
465 static void virtio_mem_resize_usable_region(VirtIOMEM *vmem,
466                                             uint64_t requested_size,
467                                             bool can_shrink)
468 {
469     uint64_t newsize = MIN(memory_region_size(&vmem->memdev->mr),
470                            requested_size + VIRTIO_MEM_USABLE_EXTENT);
471 
472     /* The usable region size always has to be multiples of the block size. */
473     newsize = QEMU_ALIGN_UP(newsize, vmem->block_size);
474 
475     if (!requested_size) {
476         newsize = 0;
477     }
478 
479     if (newsize < vmem->usable_region_size && !can_shrink) {
480         return;
481     }
482 
483     trace_virtio_mem_resized_usable_region(vmem->usable_region_size, newsize);
484     vmem->usable_region_size = newsize;
485 }
486 
487 static int virtio_mem_unplug_all(VirtIOMEM *vmem)
488 {
489     RAMBlock *rb = vmem->memdev->mr.ram_block;
490 
491     if (virtio_mem_is_busy()) {
492         return -EBUSY;
493     }
494 
495     if (ram_block_discard_range(rb, 0, qemu_ram_get_used_length(rb))) {
496         return -EBUSY;
497     }
498     virtio_mem_notify_unplug_all(vmem);
499 
500     bitmap_clear(vmem->bitmap, 0, vmem->bitmap_size);
501     if (vmem->size) {
502         vmem->size = 0;
503         notifier_list_notify(&vmem->size_change_notifiers, &vmem->size);
504     }
505     trace_virtio_mem_unplugged_all();
506     virtio_mem_resize_usable_region(vmem, vmem->requested_size, true);
507     return 0;
508 }
509 
510 static void virtio_mem_unplug_all_request(VirtIOMEM *vmem,
511                                           VirtQueueElement *elem)
512 {
513     trace_virtio_mem_unplug_all_request();
514     if (virtio_mem_unplug_all(vmem)) {
515         virtio_mem_send_response_simple(vmem, elem, VIRTIO_MEM_RESP_BUSY);
516     } else {
517         virtio_mem_send_response_simple(vmem, elem, VIRTIO_MEM_RESP_ACK);
518     }
519 }
520 
521 static void virtio_mem_state_request(VirtIOMEM *vmem, VirtQueueElement *elem,
522                                      struct virtio_mem_req *req)
523 {
524     const uint16_t nb_blocks = le16_to_cpu(req->u.state.nb_blocks);
525     const uint64_t gpa = le64_to_cpu(req->u.state.addr);
526     const uint64_t size = nb_blocks * vmem->block_size;
527     struct virtio_mem_resp resp = {
528         .type = cpu_to_le16(VIRTIO_MEM_RESP_ACK),
529     };
530 
531     trace_virtio_mem_state_request(gpa, nb_blocks);
532     if (!virtio_mem_valid_range(vmem, gpa, size)) {
533         virtio_mem_send_response_simple(vmem, elem, VIRTIO_MEM_RESP_ERROR);
534         return;
535     }
536 
537     if (virtio_mem_test_bitmap(vmem, gpa, size, true)) {
538         resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_PLUGGED);
539     } else if (virtio_mem_test_bitmap(vmem, gpa, size, false)) {
540         resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_UNPLUGGED);
541     } else {
542         resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_MIXED);
543     }
544     trace_virtio_mem_state_response(le16_to_cpu(resp.u.state.state));
545     virtio_mem_send_response(vmem, elem, &resp);
546 }
547 
548 static void virtio_mem_handle_request(VirtIODevice *vdev, VirtQueue *vq)
549 {
550     const int len = sizeof(struct virtio_mem_req);
551     VirtIOMEM *vmem = VIRTIO_MEM(vdev);
552     VirtQueueElement *elem;
553     struct virtio_mem_req req;
554     uint16_t type;
555 
556     while (true) {
557         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
558         if (!elem) {
559             return;
560         }
561 
562         if (iov_to_buf(elem->out_sg, elem->out_num, 0, &req, len) < len) {
563             virtio_error(vdev, "virtio-mem protocol violation: invalid request"
564                          " size: %d", len);
565             virtqueue_detach_element(vq, elem, 0);
566             g_free(elem);
567             return;
568         }
569 
570         if (iov_size(elem->in_sg, elem->in_num) <
571             sizeof(struct virtio_mem_resp)) {
572             virtio_error(vdev, "virtio-mem protocol violation: not enough space"
573                          " for response: %zu",
574                          iov_size(elem->in_sg, elem->in_num));
575             virtqueue_detach_element(vq, elem, 0);
576             g_free(elem);
577             return;
578         }
579 
580         type = le16_to_cpu(req.type);
581         switch (type) {
582         case VIRTIO_MEM_REQ_PLUG:
583             virtio_mem_plug_request(vmem, elem, &req);
584             break;
585         case VIRTIO_MEM_REQ_UNPLUG:
586             virtio_mem_unplug_request(vmem, elem, &req);
587             break;
588         case VIRTIO_MEM_REQ_UNPLUG_ALL:
589             virtio_mem_unplug_all_request(vmem, elem);
590             break;
591         case VIRTIO_MEM_REQ_STATE:
592             virtio_mem_state_request(vmem, elem, &req);
593             break;
594         default:
595             virtio_error(vdev, "virtio-mem protocol violation: unknown request"
596                          " type: %d", type);
597             virtqueue_detach_element(vq, elem, 0);
598             g_free(elem);
599             return;
600         }
601 
602         g_free(elem);
603     }
604 }
605 
606 static void virtio_mem_get_config(VirtIODevice *vdev, uint8_t *config_data)
607 {
608     VirtIOMEM *vmem = VIRTIO_MEM(vdev);
609     struct virtio_mem_config *config = (void *) config_data;
610 
611     config->block_size = cpu_to_le64(vmem->block_size);
612     config->node_id = cpu_to_le16(vmem->node);
613     config->requested_size = cpu_to_le64(vmem->requested_size);
614     config->plugged_size = cpu_to_le64(vmem->size);
615     config->addr = cpu_to_le64(vmem->addr);
616     config->region_size = cpu_to_le64(memory_region_size(&vmem->memdev->mr));
617     config->usable_region_size = cpu_to_le64(vmem->usable_region_size);
618 }
619 
620 static uint64_t virtio_mem_get_features(VirtIODevice *vdev, uint64_t features,
621                                         Error **errp)
622 {
623     MachineState *ms = MACHINE(qdev_get_machine());
624 
625     if (ms->numa_state) {
626 #if defined(CONFIG_ACPI)
627         virtio_add_feature(&features, VIRTIO_MEM_F_ACPI_PXM);
628 #endif
629     }
630     return features;
631 }
632 
633 static void virtio_mem_system_reset(void *opaque)
634 {
635     VirtIOMEM *vmem = VIRTIO_MEM(opaque);
636 
637     /*
638      * During usual resets, we will unplug all memory and shrink the usable
639      * region size. This is, however, not possible in all scenarios. Then,
640      * the guest has to deal with this manually (VIRTIO_MEM_REQ_UNPLUG_ALL).
641      */
642     virtio_mem_unplug_all(vmem);
643 }
644 
645 static void virtio_mem_device_realize(DeviceState *dev, Error **errp)
646 {
647     MachineState *ms = MACHINE(qdev_get_machine());
648     int nb_numa_nodes = ms->numa_state ? ms->numa_state->num_nodes : 0;
649     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
650     VirtIOMEM *vmem = VIRTIO_MEM(dev);
651     uint64_t page_size;
652     RAMBlock *rb;
653     int ret;
654 
655     if (!vmem->memdev) {
656         error_setg(errp, "'%s' property is not set", VIRTIO_MEM_MEMDEV_PROP);
657         return;
658     } else if (host_memory_backend_is_mapped(vmem->memdev)) {
659         error_setg(errp, "'%s' property specifies a busy memdev: %s",
660                    VIRTIO_MEM_MEMDEV_PROP,
661                    object_get_canonical_path_component(OBJECT(vmem->memdev)));
662         return;
663     } else if (!memory_region_is_ram(&vmem->memdev->mr) ||
664         memory_region_is_rom(&vmem->memdev->mr) ||
665         !vmem->memdev->mr.ram_block) {
666         error_setg(errp, "'%s' property specifies an unsupported memdev",
667                    VIRTIO_MEM_MEMDEV_PROP);
668         return;
669     }
670 
671     if ((nb_numa_nodes && vmem->node >= nb_numa_nodes) ||
672         (!nb_numa_nodes && vmem->node)) {
673         error_setg(errp, "'%s' property has value '%" PRIu32 "', which exceeds"
674                    "the number of numa nodes: %d", VIRTIO_MEM_NODE_PROP,
675                    vmem->node, nb_numa_nodes ? nb_numa_nodes : 1);
676         return;
677     }
678 
679     if (enable_mlock) {
680         error_setg(errp, "Incompatible with mlock");
681         return;
682     }
683 
684     rb = vmem->memdev->mr.ram_block;
685     page_size = qemu_ram_pagesize(rb);
686 
687     /*
688      * If the block size wasn't configured by the user, use a sane default. This
689      * allows using hugetlbfs backends of any page size without manual
690      * intervention.
691      */
692     if (!vmem->block_size) {
693         vmem->block_size = virtio_mem_default_block_size(rb);
694     }
695 
696     if (vmem->block_size < page_size) {
697         error_setg(errp, "'%s' property has to be at least the page size (0x%"
698                    PRIx64 ")", VIRTIO_MEM_BLOCK_SIZE_PROP, page_size);
699         return;
700     } else if (vmem->block_size < virtio_mem_default_block_size(rb)) {
701         warn_report("'%s' property is smaller than the default block size (%"
702                     PRIx64 " MiB)", VIRTIO_MEM_BLOCK_SIZE_PROP,
703                     virtio_mem_default_block_size(rb) / MiB);
704     } else if (!QEMU_IS_ALIGNED(vmem->requested_size, vmem->block_size)) {
705         error_setg(errp, "'%s' property has to be multiples of '%s' (0x%" PRIx64
706                    ")", VIRTIO_MEM_REQUESTED_SIZE_PROP,
707                    VIRTIO_MEM_BLOCK_SIZE_PROP, vmem->block_size);
708         return;
709     } else if (!QEMU_IS_ALIGNED(vmem->addr, vmem->block_size)) {
710         error_setg(errp, "'%s' property has to be multiples of '%s' (0x%" PRIx64
711                    ")", VIRTIO_MEM_ADDR_PROP, VIRTIO_MEM_BLOCK_SIZE_PROP,
712                    vmem->block_size);
713         return;
714     } else if (!QEMU_IS_ALIGNED(memory_region_size(&vmem->memdev->mr),
715                                 vmem->block_size)) {
716         error_setg(errp, "'%s' property memdev size has to be multiples of"
717                    "'%s' (0x%" PRIx64 ")", VIRTIO_MEM_MEMDEV_PROP,
718                    VIRTIO_MEM_BLOCK_SIZE_PROP, vmem->block_size);
719         return;
720     }
721 
722     if (ram_block_coordinated_discard_require(true)) {
723         error_setg(errp, "Discarding RAM is disabled");
724         return;
725     }
726 
727     ret = ram_block_discard_range(rb, 0, qemu_ram_get_used_length(rb));
728     if (ret) {
729         error_setg_errno(errp, -ret, "Unexpected error discarding RAM");
730         ram_block_coordinated_discard_require(false);
731         return;
732     }
733 
734     virtio_mem_resize_usable_region(vmem, vmem->requested_size, true);
735 
736     vmem->bitmap_size = memory_region_size(&vmem->memdev->mr) /
737                         vmem->block_size;
738     vmem->bitmap = bitmap_new(vmem->bitmap_size);
739 
740     virtio_init(vdev, TYPE_VIRTIO_MEM, VIRTIO_ID_MEM,
741                 sizeof(struct virtio_mem_config));
742     vmem->vq = virtio_add_queue(vdev, 128, virtio_mem_handle_request);
743 
744     host_memory_backend_set_mapped(vmem->memdev, true);
745     vmstate_register_ram(&vmem->memdev->mr, DEVICE(vmem));
746     qemu_register_reset(virtio_mem_system_reset, vmem);
747     precopy_add_notifier(&vmem->precopy_notifier);
748 
749     /*
750      * Set ourselves as RamDiscardManager before the plug handler maps the
751      * memory region and exposes it via an address space.
752      */
753     memory_region_set_ram_discard_manager(&vmem->memdev->mr,
754                                           RAM_DISCARD_MANAGER(vmem));
755 }
756 
757 static void virtio_mem_device_unrealize(DeviceState *dev)
758 {
759     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
760     VirtIOMEM *vmem = VIRTIO_MEM(dev);
761 
762     /*
763      * The unplug handler unmapped the memory region, it cannot be
764      * found via an address space anymore. Unset ourselves.
765      */
766     memory_region_set_ram_discard_manager(&vmem->memdev->mr, NULL);
767     precopy_remove_notifier(&vmem->precopy_notifier);
768     qemu_unregister_reset(virtio_mem_system_reset, vmem);
769     vmstate_unregister_ram(&vmem->memdev->mr, DEVICE(vmem));
770     host_memory_backend_set_mapped(vmem->memdev, false);
771     virtio_del_queue(vdev, 0);
772     virtio_cleanup(vdev);
773     g_free(vmem->bitmap);
774     ram_block_coordinated_discard_require(false);
775 }
776 
777 static int virtio_mem_discard_range_cb(const VirtIOMEM *vmem, void *arg,
778                                        uint64_t offset, uint64_t size)
779 {
780     RAMBlock *rb = vmem->memdev->mr.ram_block;
781 
782     return ram_block_discard_range(rb, offset, size) ? -EINVAL : 0;
783 }
784 
785 static int virtio_mem_restore_unplugged(VirtIOMEM *vmem)
786 {
787     /* Make sure all memory is really discarded after migration. */
788     return virtio_mem_for_each_unplugged_range(vmem, NULL,
789                                                virtio_mem_discard_range_cb);
790 }
791 
792 static int virtio_mem_post_load(void *opaque, int version_id)
793 {
794     VirtIOMEM *vmem = VIRTIO_MEM(opaque);
795     RamDiscardListener *rdl;
796     int ret;
797 
798     /*
799      * We started out with all memory discarded and our memory region is mapped
800      * into an address space. Replay, now that we updated the bitmap.
801      */
802     QLIST_FOREACH(rdl, &vmem->rdl_list, next) {
803         ret = virtio_mem_for_each_plugged_section(vmem, rdl->section, rdl,
804                                                  virtio_mem_notify_populate_cb);
805         if (ret) {
806             return ret;
807         }
808     }
809 
810     if (migration_in_incoming_postcopy()) {
811         return 0;
812     }
813 
814     return virtio_mem_restore_unplugged(vmem);
815 }
816 
817 typedef struct VirtIOMEMMigSanityChecks {
818     VirtIOMEM *parent;
819     uint64_t addr;
820     uint64_t region_size;
821     uint64_t block_size;
822     uint32_t node;
823 } VirtIOMEMMigSanityChecks;
824 
825 static int virtio_mem_mig_sanity_checks_pre_save(void *opaque)
826 {
827     VirtIOMEMMigSanityChecks *tmp = opaque;
828     VirtIOMEM *vmem = tmp->parent;
829 
830     tmp->addr = vmem->addr;
831     tmp->region_size = memory_region_size(&vmem->memdev->mr);
832     tmp->block_size = vmem->block_size;
833     tmp->node = vmem->node;
834     return 0;
835 }
836 
837 static int virtio_mem_mig_sanity_checks_post_load(void *opaque, int version_id)
838 {
839     VirtIOMEMMigSanityChecks *tmp = opaque;
840     VirtIOMEM *vmem = tmp->parent;
841     const uint64_t new_region_size = memory_region_size(&vmem->memdev->mr);
842 
843     if (tmp->addr != vmem->addr) {
844         error_report("Property '%s' changed from 0x%" PRIx64 " to 0x%" PRIx64,
845                      VIRTIO_MEM_ADDR_PROP, tmp->addr, vmem->addr);
846         return -EINVAL;
847     }
848     /*
849      * Note: Preparation for resizeable memory regions. The maximum size
850      * of the memory region must not change during migration.
851      */
852     if (tmp->region_size != new_region_size) {
853         error_report("Property '%s' size changed from 0x%" PRIx64 " to 0x%"
854                      PRIx64, VIRTIO_MEM_MEMDEV_PROP, tmp->region_size,
855                      new_region_size);
856         return -EINVAL;
857     }
858     if (tmp->block_size != vmem->block_size) {
859         error_report("Property '%s' changed from 0x%" PRIx64 " to 0x%" PRIx64,
860                      VIRTIO_MEM_BLOCK_SIZE_PROP, tmp->block_size,
861                      vmem->block_size);
862         return -EINVAL;
863     }
864     if (tmp->node != vmem->node) {
865         error_report("Property '%s' changed from %" PRIu32 " to %" PRIu32,
866                      VIRTIO_MEM_NODE_PROP, tmp->node, vmem->node);
867         return -EINVAL;
868     }
869     return 0;
870 }
871 
872 static const VMStateDescription vmstate_virtio_mem_sanity_checks = {
873     .name = "virtio-mem-device/sanity-checks",
874     .pre_save = virtio_mem_mig_sanity_checks_pre_save,
875     .post_load = virtio_mem_mig_sanity_checks_post_load,
876     .fields = (VMStateField[]) {
877         VMSTATE_UINT64(addr, VirtIOMEMMigSanityChecks),
878         VMSTATE_UINT64(region_size, VirtIOMEMMigSanityChecks),
879         VMSTATE_UINT64(block_size, VirtIOMEMMigSanityChecks),
880         VMSTATE_UINT32(node, VirtIOMEMMigSanityChecks),
881         VMSTATE_END_OF_LIST(),
882     },
883 };
884 
885 static const VMStateDescription vmstate_virtio_mem_device = {
886     .name = "virtio-mem-device",
887     .minimum_version_id = 1,
888     .version_id = 1,
889     .priority = MIG_PRI_VIRTIO_MEM,
890     .post_load = virtio_mem_post_load,
891     .fields = (VMStateField[]) {
892         VMSTATE_WITH_TMP(VirtIOMEM, VirtIOMEMMigSanityChecks,
893                          vmstate_virtio_mem_sanity_checks),
894         VMSTATE_UINT64(usable_region_size, VirtIOMEM),
895         VMSTATE_UINT64(size, VirtIOMEM),
896         VMSTATE_UINT64(requested_size, VirtIOMEM),
897         VMSTATE_BITMAP(bitmap, VirtIOMEM, 0, bitmap_size),
898         VMSTATE_END_OF_LIST()
899     },
900 };
901 
902 static const VMStateDescription vmstate_virtio_mem = {
903     .name = "virtio-mem",
904     .minimum_version_id = 1,
905     .version_id = 1,
906     .fields = (VMStateField[]) {
907         VMSTATE_VIRTIO_DEVICE,
908         VMSTATE_END_OF_LIST()
909     },
910 };
911 
912 static void virtio_mem_fill_device_info(const VirtIOMEM *vmem,
913                                         VirtioMEMDeviceInfo *vi)
914 {
915     vi->memaddr = vmem->addr;
916     vi->node = vmem->node;
917     vi->requested_size = vmem->requested_size;
918     vi->size = vmem->size;
919     vi->max_size = memory_region_size(&vmem->memdev->mr);
920     vi->block_size = vmem->block_size;
921     vi->memdev = object_get_canonical_path(OBJECT(vmem->memdev));
922 }
923 
924 static MemoryRegion *virtio_mem_get_memory_region(VirtIOMEM *vmem, Error **errp)
925 {
926     if (!vmem->memdev) {
927         error_setg(errp, "'%s' property must be set", VIRTIO_MEM_MEMDEV_PROP);
928         return NULL;
929     }
930 
931     return &vmem->memdev->mr;
932 }
933 
934 static void virtio_mem_add_size_change_notifier(VirtIOMEM *vmem,
935                                                 Notifier *notifier)
936 {
937     notifier_list_add(&vmem->size_change_notifiers, notifier);
938 }
939 
940 static void virtio_mem_remove_size_change_notifier(VirtIOMEM *vmem,
941                                                    Notifier *notifier)
942 {
943     notifier_remove(notifier);
944 }
945 
946 static void virtio_mem_get_size(Object *obj, Visitor *v, const char *name,
947                                 void *opaque, Error **errp)
948 {
949     const VirtIOMEM *vmem = VIRTIO_MEM(obj);
950     uint64_t value = vmem->size;
951 
952     visit_type_size(v, name, &value, errp);
953 }
954 
955 static void virtio_mem_get_requested_size(Object *obj, Visitor *v,
956                                           const char *name, void *opaque,
957                                           Error **errp)
958 {
959     const VirtIOMEM *vmem = VIRTIO_MEM(obj);
960     uint64_t value = vmem->requested_size;
961 
962     visit_type_size(v, name, &value, errp);
963 }
964 
965 static void virtio_mem_set_requested_size(Object *obj, Visitor *v,
966                                           const char *name, void *opaque,
967                                           Error **errp)
968 {
969     VirtIOMEM *vmem = VIRTIO_MEM(obj);
970     Error *err = NULL;
971     uint64_t value;
972 
973     visit_type_size(v, name, &value, &err);
974     if (err) {
975         error_propagate(errp, err);
976         return;
977     }
978 
979     /*
980      * The block size and memory backend are not fixed until the device was
981      * realized. realize() will verify these properties then.
982      */
983     if (DEVICE(obj)->realized) {
984         if (!QEMU_IS_ALIGNED(value, vmem->block_size)) {
985             error_setg(errp, "'%s' has to be multiples of '%s' (0x%" PRIx64
986                        ")", name, VIRTIO_MEM_BLOCK_SIZE_PROP,
987                        vmem->block_size);
988             return;
989         } else if (value > memory_region_size(&vmem->memdev->mr)) {
990             error_setg(errp, "'%s' cannot exceed the memory backend size"
991                        "(0x%" PRIx64 ")", name,
992                        memory_region_size(&vmem->memdev->mr));
993             return;
994         }
995 
996         if (value != vmem->requested_size) {
997             virtio_mem_resize_usable_region(vmem, value, false);
998             vmem->requested_size = value;
999         }
1000         /*
1001          * Trigger a config update so the guest gets notified. We trigger
1002          * even if the size didn't change (especially helpful for debugging).
1003          */
1004         virtio_notify_config(VIRTIO_DEVICE(vmem));
1005     } else {
1006         vmem->requested_size = value;
1007     }
1008 }
1009 
1010 static void virtio_mem_get_block_size(Object *obj, Visitor *v, const char *name,
1011                                       void *opaque, Error **errp)
1012 {
1013     const VirtIOMEM *vmem = VIRTIO_MEM(obj);
1014     uint64_t value = vmem->block_size;
1015 
1016     /*
1017      * If not configured by the user (and we're not realized yet), use the
1018      * default block size we would use with the current memory backend.
1019      */
1020     if (!value) {
1021         if (vmem->memdev && memory_region_is_ram(&vmem->memdev->mr)) {
1022             value = virtio_mem_default_block_size(vmem->memdev->mr.ram_block);
1023         } else {
1024             value = virtio_mem_thp_size();
1025         }
1026     }
1027 
1028     visit_type_size(v, name, &value, errp);
1029 }
1030 
1031 static void virtio_mem_set_block_size(Object *obj, Visitor *v, const char *name,
1032                                       void *opaque, Error **errp)
1033 {
1034     VirtIOMEM *vmem = VIRTIO_MEM(obj);
1035     Error *err = NULL;
1036     uint64_t value;
1037 
1038     if (DEVICE(obj)->realized) {
1039         error_setg(errp, "'%s' cannot be changed", name);
1040         return;
1041     }
1042 
1043     visit_type_size(v, name, &value, &err);
1044     if (err) {
1045         error_propagate(errp, err);
1046         return;
1047     }
1048 
1049     if (value < VIRTIO_MEM_MIN_BLOCK_SIZE) {
1050         error_setg(errp, "'%s' property has to be at least 0x%" PRIx32, name,
1051                    VIRTIO_MEM_MIN_BLOCK_SIZE);
1052         return;
1053     } else if (!is_power_of_2(value)) {
1054         error_setg(errp, "'%s' property has to be a power of two", name);
1055         return;
1056     }
1057     vmem->block_size = value;
1058 }
1059 
1060 static int virtio_mem_precopy_exclude_range_cb(const VirtIOMEM *vmem, void *arg,
1061                                                uint64_t offset, uint64_t size)
1062 {
1063     void * const host = qemu_ram_get_host_addr(vmem->memdev->mr.ram_block);
1064 
1065     qemu_guest_free_page_hint(host + offset, size);
1066     return 0;
1067 }
1068 
1069 static void virtio_mem_precopy_exclude_unplugged(VirtIOMEM *vmem)
1070 {
1071     virtio_mem_for_each_unplugged_range(vmem, NULL,
1072                                         virtio_mem_precopy_exclude_range_cb);
1073 }
1074 
1075 static int virtio_mem_precopy_notify(NotifierWithReturn *n, void *data)
1076 {
1077     VirtIOMEM *vmem = container_of(n, VirtIOMEM, precopy_notifier);
1078     PrecopyNotifyData *pnd = data;
1079 
1080     switch (pnd->reason) {
1081     case PRECOPY_NOTIFY_AFTER_BITMAP_SYNC:
1082         virtio_mem_precopy_exclude_unplugged(vmem);
1083         break;
1084     default:
1085         break;
1086     }
1087 
1088     return 0;
1089 }
1090 
1091 static void virtio_mem_instance_init(Object *obj)
1092 {
1093     VirtIOMEM *vmem = VIRTIO_MEM(obj);
1094 
1095     notifier_list_init(&vmem->size_change_notifiers);
1096     vmem->precopy_notifier.notify = virtio_mem_precopy_notify;
1097     QLIST_INIT(&vmem->rdl_list);
1098 
1099     object_property_add(obj, VIRTIO_MEM_SIZE_PROP, "size", virtio_mem_get_size,
1100                         NULL, NULL, NULL);
1101     object_property_add(obj, VIRTIO_MEM_REQUESTED_SIZE_PROP, "size",
1102                         virtio_mem_get_requested_size,
1103                         virtio_mem_set_requested_size, NULL, NULL);
1104     object_property_add(obj, VIRTIO_MEM_BLOCK_SIZE_PROP, "size",
1105                         virtio_mem_get_block_size, virtio_mem_set_block_size,
1106                         NULL, NULL);
1107 }
1108 
1109 static Property virtio_mem_properties[] = {
1110     DEFINE_PROP_UINT64(VIRTIO_MEM_ADDR_PROP, VirtIOMEM, addr, 0),
1111     DEFINE_PROP_UINT32(VIRTIO_MEM_NODE_PROP, VirtIOMEM, node, 0),
1112     DEFINE_PROP_LINK(VIRTIO_MEM_MEMDEV_PROP, VirtIOMEM, memdev,
1113                      TYPE_MEMORY_BACKEND, HostMemoryBackend *),
1114     DEFINE_PROP_END_OF_LIST(),
1115 };
1116 
1117 static uint64_t virtio_mem_rdm_get_min_granularity(const RamDiscardManager *rdm,
1118                                                    const MemoryRegion *mr)
1119 {
1120     const VirtIOMEM *vmem = VIRTIO_MEM(rdm);
1121 
1122     g_assert(mr == &vmem->memdev->mr);
1123     return vmem->block_size;
1124 }
1125 
1126 static bool virtio_mem_rdm_is_populated(const RamDiscardManager *rdm,
1127                                         const MemoryRegionSection *s)
1128 {
1129     const VirtIOMEM *vmem = VIRTIO_MEM(rdm);
1130     uint64_t start_gpa = vmem->addr + s->offset_within_region;
1131     uint64_t end_gpa = start_gpa + int128_get64(s->size);
1132 
1133     g_assert(s->mr == &vmem->memdev->mr);
1134 
1135     start_gpa = QEMU_ALIGN_DOWN(start_gpa, vmem->block_size);
1136     end_gpa = QEMU_ALIGN_UP(end_gpa, vmem->block_size);
1137 
1138     if (!virtio_mem_valid_range(vmem, start_gpa, end_gpa - start_gpa)) {
1139         return false;
1140     }
1141 
1142     return virtio_mem_test_bitmap(vmem, start_gpa, end_gpa - start_gpa, true);
1143 }
1144 
1145 struct VirtIOMEMReplayData {
1146     void *fn;
1147     void *opaque;
1148 };
1149 
1150 static int virtio_mem_rdm_replay_populated_cb(MemoryRegionSection *s, void *arg)
1151 {
1152     struct VirtIOMEMReplayData *data = arg;
1153 
1154     return ((ReplayRamPopulate)data->fn)(s, data->opaque);
1155 }
1156 
1157 static int virtio_mem_rdm_replay_populated(const RamDiscardManager *rdm,
1158                                            MemoryRegionSection *s,
1159                                            ReplayRamPopulate replay_fn,
1160                                            void *opaque)
1161 {
1162     const VirtIOMEM *vmem = VIRTIO_MEM(rdm);
1163     struct VirtIOMEMReplayData data = {
1164         .fn = replay_fn,
1165         .opaque = opaque,
1166     };
1167 
1168     g_assert(s->mr == &vmem->memdev->mr);
1169     return virtio_mem_for_each_plugged_section(vmem, s, &data,
1170                                             virtio_mem_rdm_replay_populated_cb);
1171 }
1172 
1173 static void virtio_mem_rdm_register_listener(RamDiscardManager *rdm,
1174                                              RamDiscardListener *rdl,
1175                                              MemoryRegionSection *s)
1176 {
1177     VirtIOMEM *vmem = VIRTIO_MEM(rdm);
1178     int ret;
1179 
1180     g_assert(s->mr == &vmem->memdev->mr);
1181     rdl->section = memory_region_section_new_copy(s);
1182 
1183     QLIST_INSERT_HEAD(&vmem->rdl_list, rdl, next);
1184     ret = virtio_mem_for_each_plugged_section(vmem, rdl->section, rdl,
1185                                               virtio_mem_notify_populate_cb);
1186     if (ret) {
1187         error_report("%s: Replaying plugged ranges failed: %s", __func__,
1188                      strerror(-ret));
1189     }
1190 }
1191 
1192 static void virtio_mem_rdm_unregister_listener(RamDiscardManager *rdm,
1193                                                RamDiscardListener *rdl)
1194 {
1195     VirtIOMEM *vmem = VIRTIO_MEM(rdm);
1196 
1197     g_assert(rdl->section->mr == &vmem->memdev->mr);
1198     if (vmem->size) {
1199         if (rdl->double_discard_supported) {
1200             rdl->notify_discard(rdl, rdl->section);
1201         } else {
1202             virtio_mem_for_each_plugged_section(vmem, rdl->section, rdl,
1203                                                 virtio_mem_notify_discard_cb);
1204         }
1205     }
1206 
1207     memory_region_section_free_copy(rdl->section);
1208     rdl->section = NULL;
1209     QLIST_REMOVE(rdl, next);
1210 }
1211 
1212 static void virtio_mem_class_init(ObjectClass *klass, void *data)
1213 {
1214     DeviceClass *dc = DEVICE_CLASS(klass);
1215     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
1216     VirtIOMEMClass *vmc = VIRTIO_MEM_CLASS(klass);
1217     RamDiscardManagerClass *rdmc = RAM_DISCARD_MANAGER_CLASS(klass);
1218 
1219     device_class_set_props(dc, virtio_mem_properties);
1220     dc->vmsd = &vmstate_virtio_mem;
1221 
1222     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
1223     vdc->realize = virtio_mem_device_realize;
1224     vdc->unrealize = virtio_mem_device_unrealize;
1225     vdc->get_config = virtio_mem_get_config;
1226     vdc->get_features = virtio_mem_get_features;
1227     vdc->vmsd = &vmstate_virtio_mem_device;
1228 
1229     vmc->fill_device_info = virtio_mem_fill_device_info;
1230     vmc->get_memory_region = virtio_mem_get_memory_region;
1231     vmc->add_size_change_notifier = virtio_mem_add_size_change_notifier;
1232     vmc->remove_size_change_notifier = virtio_mem_remove_size_change_notifier;
1233 
1234     rdmc->get_min_granularity = virtio_mem_rdm_get_min_granularity;
1235     rdmc->is_populated = virtio_mem_rdm_is_populated;
1236     rdmc->replay_populated = virtio_mem_rdm_replay_populated;
1237     rdmc->register_listener = virtio_mem_rdm_register_listener;
1238     rdmc->unregister_listener = virtio_mem_rdm_unregister_listener;
1239 }
1240 
1241 static const TypeInfo virtio_mem_info = {
1242     .name = TYPE_VIRTIO_MEM,
1243     .parent = TYPE_VIRTIO_DEVICE,
1244     .instance_size = sizeof(VirtIOMEM),
1245     .instance_init = virtio_mem_instance_init,
1246     .class_init = virtio_mem_class_init,
1247     .class_size = sizeof(VirtIOMEMClass),
1248     .interfaces = (InterfaceInfo[]) {
1249         { TYPE_RAM_DISCARD_MANAGER },
1250         { }
1251     },
1252 };
1253 
1254 static void virtio_register_types(void)
1255 {
1256     type_register_static(&virtio_mem_info);
1257 }
1258 
1259 type_init(virtio_register_types)
1260