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qemu/hw/virtio/virtio-mem.c
David Hildenbrand ee6398d862 virtio-mem: Mark memslot alias memory regions unmergeable 
Let's mark the memslot alias memory regions as unmergable, such that
flatview and vhost won't merge adjacent memory region aliases and we can
atomically map/unmap individual aliases without affecting adjacent
alias memory regions.

This handles vhost and vfio in multiple-memslot mode correctly (which do
not support atomic memslot updates) and avoids the temporary removal of
large memslots, which can be an expensive operation. For example, vfio
might have to unpin + repin a lot of memory, which is undesired.

Message-ID: <20230926185738.277351-19-david@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
2023-10-12 14:15:22 +02:00

1900 lines
63 KiB
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/*
* Virtio MEM device
*
* Copyright (C) 2020 Red Hat, Inc.
*
* Authors:
* David Hildenbrand <david@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qemu/iov.h"
#include "qemu/cutils.h"
#include "qemu/error-report.h"
#include "qemu/units.h"
#include "sysemu/numa.h"
#include "sysemu/sysemu.h"
#include "sysemu/reset.h"
#include "sysemu/runstate.h"
#include "hw/virtio/virtio.h"
#include "hw/virtio/virtio-bus.h"
#include "hw/virtio/virtio-mem.h"
#include "qapi/error.h"
#include "qapi/visitor.h"
#include "exec/ram_addr.h"
#include "migration/misc.h"
#include "hw/boards.h"
#include "hw/qdev-properties.h"
#include CONFIG_DEVICES
#include "trace.h"
static const VMStateDescription vmstate_virtio_mem_device_early;
/*
* We only had legacy x86 guests that did not support
* VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE. Other targets don't have legacy guests.
*/
#if defined(TARGET_X86_64) || defined(TARGET_I386)
#define VIRTIO_MEM_HAS_LEGACY_GUESTS
#endif
/*
* Let's not allow blocks smaller than 1 MiB, for example, to keep the tracking
* bitmap small.
*/
#define VIRTIO_MEM_MIN_BLOCK_SIZE ((uint32_t)(1 * MiB))
static uint32_t virtio_mem_default_thp_size(void)
{
uint32_t default_thp_size = VIRTIO_MEM_MIN_BLOCK_SIZE;
#if defined(__x86_64__) || defined(__arm__) || defined(__powerpc64__)
default_thp_size = 2 * MiB;
#elif defined(__aarch64__)
if (qemu_real_host_page_size() == 4 * KiB) {
default_thp_size = 2 * MiB;
} else if (qemu_real_host_page_size() == 16 * KiB) {
default_thp_size = 32 * MiB;
} else if (qemu_real_host_page_size() == 64 * KiB) {
default_thp_size = 512 * MiB;
}
#endif
return default_thp_size;
}
/*
* The minimum memslot size depends on this setting ("sane default"), the
* device block size, and the memory backend page size. The last (or single)
* memslot might be smaller than this constant.
*/
#define VIRTIO_MEM_MIN_MEMSLOT_SIZE (1 * GiB)
/*
* We want to have a reasonable default block size such that
* 1. We avoid splitting THPs when unplugging memory, which degrades
* performance.
* 2. We avoid placing THPs for plugged blocks that also cover unplugged
* blocks.
*
* The actual THP size might differ between Linux kernels, so we try to probe
* it. In the future (if we ever run into issues regarding 2.), we might want
* to disable THP in case we fail to properly probe the THP size, or if the
* block size is configured smaller than the THP size.
*/
static uint32_t thp_size;
#define HPAGE_PMD_SIZE_PATH "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size"
static uint32_t virtio_mem_thp_size(void)
{
gchar *content = NULL;
const char *endptr;
uint64_t tmp;
if (thp_size) {
return thp_size;
}
/*
* Try to probe the actual THP size, fallback to (sane but eventually
* incorrect) default sizes.
*/
if (g_file_get_contents(HPAGE_PMD_SIZE_PATH, &content, NULL, NULL) &&
!qemu_strtou64(content, &endptr, 0, &tmp) &&
(!endptr || *endptr == '\n')) {
/* Sanity-check the value and fallback to something reasonable. */
if (!tmp || !is_power_of_2(tmp)) {
warn_report("Read unsupported THP size: %" PRIx64, tmp);
} else {
thp_size = tmp;
}
}
if (!thp_size) {
thp_size = virtio_mem_default_thp_size();
warn_report("Could not detect THP size, falling back to %" PRIx64
" MiB.", thp_size / MiB);
}
g_free(content);
return thp_size;
}
static uint64_t virtio_mem_default_block_size(RAMBlock *rb)
{
const uint64_t page_size = qemu_ram_pagesize(rb);
/* We can have hugetlbfs with a page size smaller than the THP size. */
if (page_size == qemu_real_host_page_size()) {
return MAX(page_size, virtio_mem_thp_size());
}
return MAX(page_size, VIRTIO_MEM_MIN_BLOCK_SIZE);
}
#if defined(VIRTIO_MEM_HAS_LEGACY_GUESTS)
static bool virtio_mem_has_shared_zeropage(RAMBlock *rb)
{
/*
* We only have a guaranteed shared zeropage on ordinary MAP_PRIVATE
* anonymous RAM. In any other case, reading unplugged *can* populate a
* fresh page, consuming actual memory.
*/
return !qemu_ram_is_shared(rb) && qemu_ram_get_fd(rb) < 0 &&
qemu_ram_pagesize(rb) == qemu_real_host_page_size();
}
#endif /* VIRTIO_MEM_HAS_LEGACY_GUESTS */
/*
* Size the usable region bigger than the requested size if possible. Esp.
* Linux guests will only add (aligned) memory blocks in case they fully
* fit into the usable region, but plug+online only a subset of the pages.
* The memory block size corresponds mostly to the section size.
*
* This allows e.g., to add 20MB with a section size of 128MB on x86_64, and
* a section size of 512MB on arm64 (as long as the start address is properly
* aligned, similar to ordinary DIMMs).
*
* We can change this at any time and maybe even make it configurable if
* necessary (as the section size can change). But it's more likely that the
* section size will rather get smaller and not bigger over time.
*/
#if defined(TARGET_X86_64) || defined(TARGET_I386)
#define VIRTIO_MEM_USABLE_EXTENT (2 * (128 * MiB))
#elif defined(TARGET_ARM)
#define VIRTIO_MEM_USABLE_EXTENT (2 * (512 * MiB))
#else
#error VIRTIO_MEM_USABLE_EXTENT not defined
#endif
static bool virtio_mem_is_busy(void)
{
/*
* Postcopy cannot handle concurrent discards and we don't want to migrate
* pages on-demand with stale content when plugging new blocks.
*
* For precopy, we don't want unplugged blocks in our migration stream, and
* when plugging new blocks, the page content might differ between source
* and destination (observable by the guest when not initializing pages
* after plugging them) until we're running on the destination (as we didn't
* migrate these blocks when they were unplugged).
*/
return migration_in_incoming_postcopy() || !migration_is_idle();
}
typedef int (*virtio_mem_range_cb)(VirtIOMEM *vmem, void *arg,
uint64_t offset, uint64_t size);
static int virtio_mem_for_each_unplugged_range(VirtIOMEM *vmem, void *arg,
virtio_mem_range_cb cb)
{
unsigned long first_zero_bit, last_zero_bit;
uint64_t offset, size;
int ret = 0;
first_zero_bit = find_first_zero_bit(vmem->bitmap, vmem->bitmap_size);
while (first_zero_bit < vmem->bitmap_size) {
offset = first_zero_bit * vmem->block_size;
last_zero_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size,
first_zero_bit + 1) - 1;
size = (last_zero_bit - first_zero_bit + 1) * vmem->block_size;
ret = cb(vmem, arg, offset, size);
if (ret) {
break;
}
first_zero_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size,
last_zero_bit + 2);
}
return ret;
}
static int virtio_mem_for_each_plugged_range(VirtIOMEM *vmem, void *arg,
virtio_mem_range_cb cb)
{
unsigned long first_bit, last_bit;
uint64_t offset, size;
int ret = 0;
first_bit = find_first_bit(vmem->bitmap, vmem->bitmap_size);
while (first_bit < vmem->bitmap_size) {
offset = first_bit * vmem->block_size;
last_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size,
first_bit + 1) - 1;
size = (last_bit - first_bit + 1) * vmem->block_size;
ret = cb(vmem, arg, offset, size);
if (ret) {
break;
}
first_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size,
last_bit + 2);
}
return ret;
}
/*
* Adjust the memory section to cover the intersection with the given range.
*
* Returns false if the intersection is empty, otherwise returns true.
*/
static bool virtio_mem_intersect_memory_section(MemoryRegionSection *s,
uint64_t offset, uint64_t size)
{
uint64_t start = MAX(s->offset_within_region, offset);
uint64_t end = MIN(s->offset_within_region + int128_get64(s->size),
offset + size);
if (end <= start) {
return false;
}
s->offset_within_address_space += start - s->offset_within_region;
s->offset_within_region = start;
s->size = int128_make64(end - start);
return true;
}
typedef int (*virtio_mem_section_cb)(MemoryRegionSection *s, void *arg);
static int virtio_mem_for_each_plugged_section(const VirtIOMEM *vmem,
MemoryRegionSection *s,
void *arg,
virtio_mem_section_cb cb)
{
unsigned long first_bit, last_bit;
uint64_t offset, size;
int ret = 0;
first_bit = s->offset_within_region / vmem->block_size;
first_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size, first_bit);
while (first_bit < vmem->bitmap_size) {
MemoryRegionSection tmp = *s;
offset = first_bit * vmem->block_size;
last_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size,
first_bit + 1) - 1;
size = (last_bit - first_bit + 1) * vmem->block_size;
if (!virtio_mem_intersect_memory_section(&tmp, offset, size)) {
break;
}
ret = cb(&tmp, arg);
if (ret) {
break;
}
first_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size,
last_bit + 2);
}
return ret;
}
static int virtio_mem_for_each_unplugged_section(const VirtIOMEM *vmem,
MemoryRegionSection *s,
void *arg,
virtio_mem_section_cb cb)
{
unsigned long first_bit, last_bit;
uint64_t offset, size;
int ret = 0;
first_bit = s->offset_within_region / vmem->block_size;
first_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size, first_bit);
while (first_bit < vmem->bitmap_size) {
MemoryRegionSection tmp = *s;
offset = first_bit * vmem->block_size;
last_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size,
first_bit + 1) - 1;
size = (last_bit - first_bit + 1) * vmem->block_size;
if (!virtio_mem_intersect_memory_section(&tmp, offset, size)) {
break;
}
ret = cb(&tmp, arg);
if (ret) {
break;
}
first_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size,
last_bit + 2);
}
return ret;
}
static int virtio_mem_notify_populate_cb(MemoryRegionSection *s, void *arg)
{
RamDiscardListener *rdl = arg;
return rdl->notify_populate(rdl, s);
}
static int virtio_mem_notify_discard_cb(MemoryRegionSection *s, void *arg)
{
RamDiscardListener *rdl = arg;
rdl->notify_discard(rdl, s);
return 0;
}
static void virtio_mem_notify_unplug(VirtIOMEM *vmem, uint64_t offset,
uint64_t size)
{
RamDiscardListener *rdl;
QLIST_FOREACH(rdl, &vmem->rdl_list, next) {
MemoryRegionSection tmp = *rdl->section;
if (!virtio_mem_intersect_memory_section(&tmp, offset, size)) {
continue;
}
rdl->notify_discard(rdl, &tmp);
}
}
static int virtio_mem_notify_plug(VirtIOMEM *vmem, uint64_t offset,
uint64_t size)
{
RamDiscardListener *rdl, *rdl2;
int ret = 0;
QLIST_FOREACH(rdl, &vmem->rdl_list, next) {
MemoryRegionSection tmp = *rdl->section;
if (!virtio_mem_intersect_memory_section(&tmp, offset, size)) {
continue;
}
ret = rdl->notify_populate(rdl, &tmp);
if (ret) {
break;
}
}
if (ret) {
/* Notify all already-notified listeners. */
QLIST_FOREACH(rdl2, &vmem->rdl_list, next) {
MemoryRegionSection tmp = *rdl2->section;
if (rdl2 == rdl) {
break;
}
if (!virtio_mem_intersect_memory_section(&tmp, offset, size)) {
continue;
}
rdl2->notify_discard(rdl2, &tmp);
}
}
return ret;
}
static void virtio_mem_notify_unplug_all(VirtIOMEM *vmem)
{
RamDiscardListener *rdl;
if (!vmem->size) {
return;
}
QLIST_FOREACH(rdl, &vmem->rdl_list, next) {
if (rdl->double_discard_supported) {
rdl->notify_discard(rdl, rdl->section);
} else {
virtio_mem_for_each_plugged_section(vmem, rdl->section, rdl,
virtio_mem_notify_discard_cb);
}
}
}
static bool virtio_mem_is_range_plugged(const VirtIOMEM *vmem,
uint64_t start_gpa, uint64_t size)
{
const unsigned long first_bit = (start_gpa - vmem->addr) / vmem->block_size;
const unsigned long last_bit = first_bit + (size / vmem->block_size) - 1;
unsigned long found_bit;
/* We fake a shorter bitmap to avoid searching too far. */
found_bit = find_next_zero_bit(vmem->bitmap, last_bit + 1, first_bit);
return found_bit > last_bit;
}
static bool virtio_mem_is_range_unplugged(const VirtIOMEM *vmem,
uint64_t start_gpa, uint64_t size)
{
const unsigned long first_bit = (start_gpa - vmem->addr) / vmem->block_size;
const unsigned long last_bit = first_bit + (size / vmem->block_size) - 1;
unsigned long found_bit;
/* We fake a shorter bitmap to avoid searching too far. */
found_bit = find_next_bit(vmem->bitmap, last_bit + 1, first_bit);
return found_bit > last_bit;
}
static void virtio_mem_set_range_plugged(VirtIOMEM *vmem, uint64_t start_gpa,
uint64_t size)
{
const unsigned long bit = (start_gpa - vmem->addr) / vmem->block_size;
const unsigned long nbits = size / vmem->block_size;
bitmap_set(vmem->bitmap, bit, nbits);
}
static void virtio_mem_set_range_unplugged(VirtIOMEM *vmem, uint64_t start_gpa,
uint64_t size)
{
const unsigned long bit = (start_gpa - vmem->addr) / vmem->block_size;
const unsigned long nbits = size / vmem->block_size;
bitmap_clear(vmem->bitmap, bit, nbits);
}
static void virtio_mem_send_response(VirtIOMEM *vmem, VirtQueueElement *elem,
struct virtio_mem_resp *resp)
{
VirtIODevice *vdev = VIRTIO_DEVICE(vmem);
VirtQueue *vq = vmem->vq;
trace_virtio_mem_send_response(le16_to_cpu(resp->type));
iov_from_buf(elem->in_sg, elem->in_num, 0, resp, sizeof(*resp));
virtqueue_push(vq, elem, sizeof(*resp));
virtio_notify(vdev, vq);
}
static void virtio_mem_send_response_simple(VirtIOMEM *vmem,
VirtQueueElement *elem,
uint16_t type)
{
struct virtio_mem_resp resp = {
.type = cpu_to_le16(type),
};
virtio_mem_send_response(vmem, elem, &resp);
}
static bool virtio_mem_valid_range(const VirtIOMEM *vmem, uint64_t gpa,
uint64_t size)
{
if (!QEMU_IS_ALIGNED(gpa, vmem->block_size)) {
return false;
}
if (gpa + size < gpa || !size) {
return false;
}
if (gpa < vmem->addr || gpa >= vmem->addr + vmem->usable_region_size) {
return false;
}
if (gpa + size > vmem->addr + vmem->usable_region_size) {
return false;
}
return true;
}
static void virtio_mem_activate_memslot(VirtIOMEM *vmem, unsigned int idx)
{
const uint64_t memslot_offset = idx * vmem->memslot_size;
assert(vmem->memslots);
/*
* Instead of enabling/disabling memslots, we add/remove them. This should
* make address space updates faster, because we don't have to loop over
* many disabled subregions.
*/
if (memory_region_is_mapped(&vmem->memslots[idx])) {
return;
}
memory_region_add_subregion(vmem->mr, memslot_offset, &vmem->memslots[idx]);
}
static void virtio_mem_deactivate_memslot(VirtIOMEM *vmem, unsigned int idx)
{
assert(vmem->memslots);
if (!memory_region_is_mapped(&vmem->memslots[idx])) {
return;
}
memory_region_del_subregion(vmem->mr, &vmem->memslots[idx]);
}
static void virtio_mem_activate_memslots_to_plug(VirtIOMEM *vmem,
uint64_t offset, uint64_t size)
{
const unsigned int start_idx = offset / vmem->memslot_size;
const unsigned int end_idx = (offset + size + vmem->memslot_size - 1) /
vmem->memslot_size;
unsigned int idx;
if (!vmem->dynamic_memslots) {
return;
}
/* Activate all involved memslots in a single transaction. */
memory_region_transaction_begin();
for (idx = start_idx; idx < end_idx; idx++) {
virtio_mem_activate_memslot(vmem, idx);
}
memory_region_transaction_commit();
}
static void virtio_mem_deactivate_unplugged_memslots(VirtIOMEM *vmem,
uint64_t offset,
uint64_t size)
{
const uint64_t region_size = memory_region_size(&vmem->memdev->mr);
const unsigned int start_idx = offset / vmem->memslot_size;
const unsigned int end_idx = (offset + size + vmem->memslot_size - 1) /
vmem->memslot_size;
unsigned int idx;
if (!vmem->dynamic_memslots) {
return;
}
/* Deactivate all memslots with unplugged blocks in a single transaction. */
memory_region_transaction_begin();
for (idx = start_idx; idx < end_idx; idx++) {
const uint64_t memslot_offset = idx * vmem->memslot_size;
uint64_t memslot_size = vmem->memslot_size;
/* The size of the last memslot might be smaller. */
if (idx == vmem->nb_memslots - 1) {
memslot_size = region_size - memslot_offset;
}
/*
* Partially covered memslots might still have some blocks plugged and
* have to remain active if that's the case.
*/
if (offset > memslot_offset ||
offset + size < memslot_offset + memslot_size) {
const uint64_t gpa = vmem->addr + memslot_offset;
if (!virtio_mem_is_range_unplugged(vmem, gpa, memslot_size)) {
continue;
}
}
virtio_mem_deactivate_memslot(vmem, idx);
}
memory_region_transaction_commit();
}
static int virtio_mem_set_block_state(VirtIOMEM *vmem, uint64_t start_gpa,
uint64_t size, bool plug)
{
const uint64_t offset = start_gpa - vmem->addr;
RAMBlock *rb = vmem->memdev->mr.ram_block;
int ret = 0;
if (virtio_mem_is_busy()) {
return -EBUSY;
}
if (!plug) {
if (ram_block_discard_range(rb, offset, size)) {
return -EBUSY;
}
virtio_mem_notify_unplug(vmem, offset, size);
virtio_mem_set_range_unplugged(vmem, start_gpa, size);
/* Deactivate completely unplugged memslots after updating the state. */
virtio_mem_deactivate_unplugged_memslots(vmem, offset, size);
return 0;
}
if (vmem->prealloc) {
void *area = memory_region_get_ram_ptr(&vmem->memdev->mr) + offset;
int fd = memory_region_get_fd(&vmem->memdev->mr);
Error *local_err = NULL;
qemu_prealloc_mem(fd, area, size, 1, NULL, &local_err);
if (local_err) {
static bool warned;
/*
* Warn only once, we don't want to fill the log with these
* warnings.
*/
if (!warned) {
warn_report_err(local_err);
warned = true;
} else {
error_free(local_err);
}
ret = -EBUSY;
}
}
if (!ret) {
/*
* Activate before notifying and rollback in case of any errors.
*
* When activating a yet inactive memslot, memory notifiers will get
* notified about the added memory region and can register with the
* RamDiscardManager; this will traverse all plugged blocks and skip the
* blocks we are plugging here. The following notification will inform
* registered listeners about the blocks we're plugging.
*/
virtio_mem_activate_memslots_to_plug(vmem, offset, size);
ret = virtio_mem_notify_plug(vmem, offset, size);
if (ret) {
virtio_mem_deactivate_unplugged_memslots(vmem, offset, size);
}
}
if (ret) {
/* Could be preallocation or a notifier populated memory. */
ram_block_discard_range(vmem->memdev->mr.ram_block, offset, size);
return -EBUSY;
}
virtio_mem_set_range_plugged(vmem, start_gpa, size);
return 0;
}
static int virtio_mem_state_change_request(VirtIOMEM *vmem, uint64_t gpa,
uint16_t nb_blocks, bool plug)
{
const uint64_t size = nb_blocks * vmem->block_size;
int ret;
if (!virtio_mem_valid_range(vmem, gpa, size)) {
return VIRTIO_MEM_RESP_ERROR;
}
if (plug && (vmem->size + size > vmem->requested_size)) {
return VIRTIO_MEM_RESP_NACK;
}
/* test if really all blocks are in the opposite state */
if ((plug && !virtio_mem_is_range_unplugged(vmem, gpa, size)) ||
(!plug && !virtio_mem_is_range_plugged(vmem, gpa, size))) {
return VIRTIO_MEM_RESP_ERROR;
}
ret = virtio_mem_set_block_state(vmem, gpa, size, plug);
if (ret) {
return VIRTIO_MEM_RESP_BUSY;
}
if (plug) {
vmem->size += size;
} else {
vmem->size -= size;
}
notifier_list_notify(&vmem->size_change_notifiers, &vmem->size);
return VIRTIO_MEM_RESP_ACK;
}
static void virtio_mem_plug_request(VirtIOMEM *vmem, VirtQueueElement *elem,
struct virtio_mem_req *req)
{
const uint64_t gpa = le64_to_cpu(req->u.plug.addr);
const uint16_t nb_blocks = le16_to_cpu(req->u.plug.nb_blocks);
uint16_t type;
trace_virtio_mem_plug_request(gpa, nb_blocks);
type = virtio_mem_state_change_request(vmem, gpa, nb_blocks, true);
virtio_mem_send_response_simple(vmem, elem, type);
}
static void virtio_mem_unplug_request(VirtIOMEM *vmem, VirtQueueElement *elem,
struct virtio_mem_req *req)
{
const uint64_t gpa = le64_to_cpu(req->u.unplug.addr);
const uint16_t nb_blocks = le16_to_cpu(req->u.unplug.nb_blocks);
uint16_t type;
trace_virtio_mem_unplug_request(gpa, nb_blocks);
type = virtio_mem_state_change_request(vmem, gpa, nb_blocks, false);
virtio_mem_send_response_simple(vmem, elem, type);
}
static void virtio_mem_resize_usable_region(VirtIOMEM *vmem,
uint64_t requested_size,
bool can_shrink)
{
uint64_t newsize = MIN(memory_region_size(&vmem->memdev->mr),
requested_size + VIRTIO_MEM_USABLE_EXTENT);
/* The usable region size always has to be multiples of the block size. */
newsize = QEMU_ALIGN_UP(newsize, vmem->block_size);
if (!requested_size) {
newsize = 0;
}
if (newsize < vmem->usable_region_size && !can_shrink) {
return;
}
trace_virtio_mem_resized_usable_region(vmem->usable_region_size, newsize);
vmem->usable_region_size = newsize;
}
static int virtio_mem_unplug_all(VirtIOMEM *vmem)
{
const uint64_t region_size = memory_region_size(&vmem->memdev->mr);
RAMBlock *rb = vmem->memdev->mr.ram_block;
if (vmem->size) {
if (virtio_mem_is_busy()) {
return -EBUSY;
}
if (ram_block_discard_range(rb, 0, qemu_ram_get_used_length(rb))) {
return -EBUSY;
}
virtio_mem_notify_unplug_all(vmem);
bitmap_clear(vmem->bitmap, 0, vmem->bitmap_size);
vmem->size = 0;
notifier_list_notify(&vmem->size_change_notifiers, &vmem->size);
/* Deactivate all memslots after updating the state. */
virtio_mem_deactivate_unplugged_memslots(vmem, 0, region_size);
}
trace_virtio_mem_unplugged_all();
virtio_mem_resize_usable_region(vmem, vmem->requested_size, true);
return 0;
}
static void virtio_mem_unplug_all_request(VirtIOMEM *vmem,
VirtQueueElement *elem)
{
trace_virtio_mem_unplug_all_request();
if (virtio_mem_unplug_all(vmem)) {
virtio_mem_send_response_simple(vmem, elem, VIRTIO_MEM_RESP_BUSY);
} else {
virtio_mem_send_response_simple(vmem, elem, VIRTIO_MEM_RESP_ACK);
}
}
static void virtio_mem_state_request(VirtIOMEM *vmem, VirtQueueElement *elem,
struct virtio_mem_req *req)
{
const uint16_t nb_blocks = le16_to_cpu(req->u.state.nb_blocks);
const uint64_t gpa = le64_to_cpu(req->u.state.addr);
const uint64_t size = nb_blocks * vmem->block_size;
struct virtio_mem_resp resp = {
.type = cpu_to_le16(VIRTIO_MEM_RESP_ACK),
};
trace_virtio_mem_state_request(gpa, nb_blocks);
if (!virtio_mem_valid_range(vmem, gpa, size)) {
virtio_mem_send_response_simple(vmem, elem, VIRTIO_MEM_RESP_ERROR);
return;
}
if (virtio_mem_is_range_plugged(vmem, gpa, size)) {
resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_PLUGGED);
} else if (virtio_mem_is_range_unplugged(vmem, gpa, size)) {
resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_UNPLUGGED);
} else {
resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_MIXED);
}
trace_virtio_mem_state_response(le16_to_cpu(resp.u.state.state));
virtio_mem_send_response(vmem, elem, &resp);
}
static void virtio_mem_handle_request(VirtIODevice *vdev, VirtQueue *vq)
{
const int len = sizeof(struct virtio_mem_req);
VirtIOMEM *vmem = VIRTIO_MEM(vdev);
VirtQueueElement *elem;
struct virtio_mem_req req;
uint16_t type;
while (true) {
elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
if (!elem) {
return;
}
if (iov_to_buf(elem->out_sg, elem->out_num, 0, &req, len) < len) {
virtio_error(vdev, "virtio-mem protocol violation: invalid request"
" size: %d", len);
virtqueue_detach_element(vq, elem, 0);
g_free(elem);
return;
}
if (iov_size(elem->in_sg, elem->in_num) <
sizeof(struct virtio_mem_resp)) {
virtio_error(vdev, "virtio-mem protocol violation: not enough space"
" for response: %zu",
iov_size(elem->in_sg, elem->in_num));
virtqueue_detach_element(vq, elem, 0);
g_free(elem);
return;
}
type = le16_to_cpu(req.type);
switch (type) {
case VIRTIO_MEM_REQ_PLUG:
virtio_mem_plug_request(vmem, elem, &req);
break;
case VIRTIO_MEM_REQ_UNPLUG:
virtio_mem_unplug_request(vmem, elem, &req);
break;
case VIRTIO_MEM_REQ_UNPLUG_ALL:
virtio_mem_unplug_all_request(vmem, elem);
break;
case VIRTIO_MEM_REQ_STATE:
virtio_mem_state_request(vmem, elem, &req);
break;
default:
virtio_error(vdev, "virtio-mem protocol violation: unknown request"
" type: %d", type);
virtqueue_detach_element(vq, elem, 0);
g_free(elem);
return;
}
g_free(elem);
}
}
static void virtio_mem_get_config(VirtIODevice *vdev, uint8_t *config_data)
{
VirtIOMEM *vmem = VIRTIO_MEM(vdev);
struct virtio_mem_config *config = (void *) config_data;
config->block_size = cpu_to_le64(vmem->block_size);
config->node_id = cpu_to_le16(vmem->node);
config->requested_size = cpu_to_le64(vmem->requested_size);
config->plugged_size = cpu_to_le64(vmem->size);
config->addr = cpu_to_le64(vmem->addr);
config->region_size = cpu_to_le64(memory_region_size(&vmem->memdev->mr));
config->usable_region_size = cpu_to_le64(vmem->usable_region_size);
}
static uint64_t virtio_mem_get_features(VirtIODevice *vdev, uint64_t features,
Error **errp)
{
MachineState *ms = MACHINE(qdev_get_machine());
VirtIOMEM *vmem = VIRTIO_MEM(vdev);
if (ms->numa_state) {
#if defined(CONFIG_ACPI)
virtio_add_feature(&features, VIRTIO_MEM_F_ACPI_PXM);
#endif
}
assert(vmem->unplugged_inaccessible != ON_OFF_AUTO_AUTO);
if (vmem->unplugged_inaccessible == ON_OFF_AUTO_ON) {
virtio_add_feature(&features, VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE);
}
return features;
}
static int virtio_mem_validate_features(VirtIODevice *vdev)
{
if (virtio_host_has_feature(vdev, VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE) &&
!virtio_vdev_has_feature(vdev, VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE)) {
return -EFAULT;
}
return 0;
}
static void virtio_mem_system_reset(void *opaque)
{
VirtIOMEM *vmem = VIRTIO_MEM(opaque);
/*
* During usual resets, we will unplug all memory and shrink the usable
* region size. This is, however, not possible in all scenarios. Then,
* the guest has to deal with this manually (VIRTIO_MEM_REQ_UNPLUG_ALL).
*/
virtio_mem_unplug_all(vmem);
}
static void virtio_mem_prepare_mr(VirtIOMEM *vmem)
{
const uint64_t region_size = memory_region_size(&vmem->memdev->mr);
assert(!vmem->mr && vmem->dynamic_memslots);
vmem->mr = g_new0(MemoryRegion, 1);
memory_region_init(vmem->mr, OBJECT(vmem), "virtio-mem",
region_size);
vmem->mr->align = memory_region_get_alignment(&vmem->memdev->mr);
}
static void virtio_mem_prepare_memslots(VirtIOMEM *vmem)
{
const uint64_t region_size = memory_region_size(&vmem->memdev->mr);
unsigned int idx;
g_assert(!vmem->memslots && vmem->nb_memslots && vmem->dynamic_memslots);
vmem->memslots = g_new0(MemoryRegion, vmem->nb_memslots);
/* Initialize our memslots, but don't map them yet. */
for (idx = 0; idx < vmem->nb_memslots; idx++) {
const uint64_t memslot_offset = idx * vmem->memslot_size;
uint64_t memslot_size = vmem->memslot_size;
char name[20];
/* The size of the last memslot might be smaller. */
if (idx == vmem->nb_memslots - 1) {
memslot_size = region_size - memslot_offset;
}
snprintf(name, sizeof(name), "memslot-%u", idx);
memory_region_init_alias(&vmem->memslots[idx], OBJECT(vmem), name,
&vmem->memdev->mr, memslot_offset,
memslot_size);
/*
* We want to be able to atomically and efficiently activate/deactivate
* individual memslots without affecting adjacent memslots in memory
* notifiers.
*/
memory_region_set_unmergeable(&vmem->memslots[idx], true);
}
}
static void virtio_mem_device_realize(DeviceState *dev, Error **errp)
{
MachineState *ms = MACHINE(qdev_get_machine());
int nb_numa_nodes = ms->numa_state ? ms->numa_state->num_nodes : 0;
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VirtIOMEM *vmem = VIRTIO_MEM(dev);
uint64_t page_size;
RAMBlock *rb;
int ret;
if (!vmem->memdev) {
error_setg(errp, "'%s' property is not set", VIRTIO_MEM_MEMDEV_PROP);
return;
} else if (host_memory_backend_is_mapped(vmem->memdev)) {
error_setg(errp, "'%s' property specifies a busy memdev: %s",
VIRTIO_MEM_MEMDEV_PROP,
object_get_canonical_path_component(OBJECT(vmem->memdev)));
return;
} else if (!memory_region_is_ram(&vmem->memdev->mr) ||
memory_region_is_rom(&vmem->memdev->mr) ||
!vmem->memdev->mr.ram_block) {
error_setg(errp, "'%s' property specifies an unsupported memdev",
VIRTIO_MEM_MEMDEV_PROP);
return;
} else if (vmem->memdev->prealloc) {
error_setg(errp, "'%s' property specifies a memdev with preallocation"
" enabled: %s. Instead, specify 'prealloc=on' for the"
" virtio-mem device. ", VIRTIO_MEM_MEMDEV_PROP,
object_get_canonical_path_component(OBJECT(vmem->memdev)));
return;
}
if ((nb_numa_nodes && vmem->node >= nb_numa_nodes) ||
(!nb_numa_nodes && vmem->node)) {
error_setg(errp, "'%s' property has value '%" PRIu32 "', which exceeds"
"the number of numa nodes: %d", VIRTIO_MEM_NODE_PROP,
vmem->node, nb_numa_nodes ? nb_numa_nodes : 1);
return;
}
if (enable_mlock) {
error_setg(errp, "Incompatible with mlock");
return;
}
rb = vmem->memdev->mr.ram_block;
page_size = qemu_ram_pagesize(rb);
#if defined(VIRTIO_MEM_HAS_LEGACY_GUESTS)
switch (vmem->unplugged_inaccessible) {
case ON_OFF_AUTO_AUTO:
if (virtio_mem_has_shared_zeropage(rb)) {
vmem->unplugged_inaccessible = ON_OFF_AUTO_OFF;
} else {
vmem->unplugged_inaccessible = ON_OFF_AUTO_ON;
}
break;
case ON_OFF_AUTO_OFF:
if (!virtio_mem_has_shared_zeropage(rb)) {
warn_report("'%s' property set to 'off' with a memdev that does"
" not support the shared zeropage.",
VIRTIO_MEM_UNPLUGGED_INACCESSIBLE_PROP);
}
break;
default:
break;
}
#else /* VIRTIO_MEM_HAS_LEGACY_GUESTS */
vmem->unplugged_inaccessible = ON_OFF_AUTO_ON;
#endif /* VIRTIO_MEM_HAS_LEGACY_GUESTS */
if (vmem->dynamic_memslots &&
vmem->unplugged_inaccessible != ON_OFF_AUTO_ON) {
error_setg(errp, "'%s' property set to 'on' requires '%s' to be 'on'",
VIRTIO_MEM_DYNAMIC_MEMSLOTS_PROP,
VIRTIO_MEM_UNPLUGGED_INACCESSIBLE_PROP);
return;
}
/*
* If the block size wasn't configured by the user, use a sane default. This
* allows using hugetlbfs backends of any page size without manual
* intervention.
*/
if (!vmem->block_size) {
vmem->block_size = virtio_mem_default_block_size(rb);
}
if (vmem->block_size < page_size) {
error_setg(errp, "'%s' property has to be at least the page size (0x%"
PRIx64 ")", VIRTIO_MEM_BLOCK_SIZE_PROP, page_size);
return;
} else if (vmem->block_size < virtio_mem_default_block_size(rb)) {
warn_report("'%s' property is smaller than the default block size (%"
PRIx64 " MiB)", VIRTIO_MEM_BLOCK_SIZE_PROP,
virtio_mem_default_block_size(rb) / MiB);
}
if (!QEMU_IS_ALIGNED(vmem->requested_size, vmem->block_size)) {
error_setg(errp, "'%s' property has to be multiples of '%s' (0x%" PRIx64
")", VIRTIO_MEM_REQUESTED_SIZE_PROP,
VIRTIO_MEM_BLOCK_SIZE_PROP, vmem->block_size);
return;
} else if (!QEMU_IS_ALIGNED(vmem->addr, vmem->block_size)) {
error_setg(errp, "'%s' property has to be multiples of '%s' (0x%" PRIx64
")", VIRTIO_MEM_ADDR_PROP, VIRTIO_MEM_BLOCK_SIZE_PROP,
vmem->block_size);
return;
} else if (!QEMU_IS_ALIGNED(memory_region_size(&vmem->memdev->mr),
vmem->block_size)) {
error_setg(errp, "'%s' property memdev size has to be multiples of"
"'%s' (0x%" PRIx64 ")", VIRTIO_MEM_MEMDEV_PROP,
VIRTIO_MEM_BLOCK_SIZE_PROP, vmem->block_size);
return;
}
if (ram_block_coordinated_discard_require(true)) {
error_setg(errp, "Discarding RAM is disabled");
return;
}
/*
* We don't know at this point whether shared RAM is migrated using
* QEMU or migrated using the file content. "x-ignore-shared" will be
* configured after realizing the device. So in case we have an
* incoming migration, simply always skip the discard step.
*
* Otherwise, make sure that we start with a clean slate: either the
* memory backend might get reused or the shared file might still have
* memory allocated.
*/
if (!runstate_check(RUN_STATE_INMIGRATE)) {
ret = ram_block_discard_range(rb, 0, qemu_ram_get_used_length(rb));
if (ret) {
error_setg_errno(errp, -ret, "Unexpected error discarding RAM");
ram_block_coordinated_discard_require(false);
return;
}
}
virtio_mem_resize_usable_region(vmem, vmem->requested_size, true);
vmem->bitmap_size = memory_region_size(&vmem->memdev->mr) /
vmem->block_size;
vmem->bitmap = bitmap_new(vmem->bitmap_size);
virtio_init(vdev, VIRTIO_ID_MEM, sizeof(struct virtio_mem_config));
vmem->vq = virtio_add_queue(vdev, 128, virtio_mem_handle_request);
/*
* With "dynamic-memslots=off" (old behavior) we always map the whole
* RAM memory region directly.
*/
if (vmem->dynamic_memslots) {
if (!vmem->mr) {
virtio_mem_prepare_mr(vmem);
}
if (vmem->nb_memslots <= 1) {
vmem->nb_memslots = 1;
vmem->memslot_size = memory_region_size(&vmem->memdev->mr);
}
if (!vmem->memslots) {
virtio_mem_prepare_memslots(vmem);
}
} else {
assert(!vmem->mr && !vmem->nb_memslots && !vmem->memslots);
}
host_memory_backend_set_mapped(vmem->memdev, true);
vmstate_register_ram(&vmem->memdev->mr, DEVICE(vmem));
if (vmem->early_migration) {
vmstate_register(VMSTATE_IF(vmem), VMSTATE_INSTANCE_ID_ANY,
&vmstate_virtio_mem_device_early, vmem);
}
qemu_register_reset(virtio_mem_system_reset, vmem);
/*
* Set ourselves as RamDiscardManager before the plug handler maps the
* memory region and exposes it via an address space.
*/
memory_region_set_ram_discard_manager(&vmem->memdev->mr,
RAM_DISCARD_MANAGER(vmem));
}
static void virtio_mem_device_unrealize(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VirtIOMEM *vmem = VIRTIO_MEM(dev);
/*
* The unplug handler unmapped the memory region, it cannot be
* found via an address space anymore. Unset ourselves.
*/
memory_region_set_ram_discard_manager(&vmem->memdev->mr, NULL);
qemu_unregister_reset(virtio_mem_system_reset, vmem);
if (vmem->early_migration) {
vmstate_unregister(VMSTATE_IF(vmem), &vmstate_virtio_mem_device_early,
vmem);
}
vmstate_unregister_ram(&vmem->memdev->mr, DEVICE(vmem));
host_memory_backend_set_mapped(vmem->memdev, false);
virtio_del_queue(vdev, 0);
virtio_cleanup(vdev);
g_free(vmem->bitmap);
ram_block_coordinated_discard_require(false);
}
static int virtio_mem_discard_range_cb(VirtIOMEM *vmem, void *arg,
uint64_t offset, uint64_t size)
{
RAMBlock *rb = vmem->memdev->mr.ram_block;
return ram_block_discard_range(rb, offset, size) ? -EINVAL : 0;
}
static int virtio_mem_restore_unplugged(VirtIOMEM *vmem)
{
/* Make sure all memory is really discarded after migration. */
return virtio_mem_for_each_unplugged_range(vmem, NULL,
virtio_mem_discard_range_cb);
}
static int virtio_mem_activate_memslot_range_cb(VirtIOMEM *vmem, void *arg,
uint64_t offset, uint64_t size)
{
virtio_mem_activate_memslots_to_plug(vmem, offset, size);
return 0;
}
static int virtio_mem_post_load_bitmap(VirtIOMEM *vmem)
{
RamDiscardListener *rdl;
int ret;
/*
* We restored the bitmap and updated the requested size; activate all
* memslots (so listeners register) before notifying about plugged blocks.
*/
if (vmem->dynamic_memslots) {
/*
* We don't expect any active memslots at this point to deactivate: no
* memory was plugged on the migration destination.
*/
virtio_mem_for_each_plugged_range(vmem, NULL,
virtio_mem_activate_memslot_range_cb);
}
/*
* We started out with all memory discarded and our memory region is mapped
* into an address space. Replay, now that we updated the bitmap.
*/
QLIST_FOREACH(rdl, &vmem->rdl_list, next) {
ret = virtio_mem_for_each_plugged_section(vmem, rdl->section, rdl,
virtio_mem_notify_populate_cb);
if (ret) {
return ret;
}
}
return 0;
}
static int virtio_mem_post_load(void *opaque, int version_id)
{
VirtIOMEM *vmem = VIRTIO_MEM(opaque);
int ret;
if (!vmem->early_migration) {
ret = virtio_mem_post_load_bitmap(vmem);
if (ret) {
return ret;
}
}
/*
* If shared RAM is migrated using the file content and not using QEMU,
* don't mess with preallocation and postcopy.
*/
if (migrate_ram_is_ignored(vmem->memdev->mr.ram_block)) {
return 0;
}
if (vmem->prealloc && !vmem->early_migration) {
warn_report("Proper preallocation with migration requires a newer QEMU machine");
}
if (migration_in_incoming_postcopy()) {
return 0;
}
return virtio_mem_restore_unplugged(vmem);
}
static int virtio_mem_prealloc_range_cb(VirtIOMEM *vmem, void *arg,
uint64_t offset, uint64_t size)
{
void *area = memory_region_get_ram_ptr(&vmem->memdev->mr) + offset;
int fd = memory_region_get_fd(&vmem->memdev->mr);
Error *local_err = NULL;
qemu_prealloc_mem(fd, area, size, 1, NULL, &local_err);
if (local_err) {
error_report_err(local_err);
return -ENOMEM;
}
return 0;
}
static int virtio_mem_post_load_early(void *opaque, int version_id)
{
VirtIOMEM *vmem = VIRTIO_MEM(opaque);
RAMBlock *rb = vmem->memdev->mr.ram_block;
int ret;
if (!vmem->prealloc) {
goto post_load_bitmap;
}
/*
* If shared RAM is migrated using the file content and not using QEMU,
* don't mess with preallocation and postcopy.
*/
if (migrate_ram_is_ignored(rb)) {
goto post_load_bitmap;
}
/*
* We restored the bitmap and verified that the basic properties
* match on source and destination, so we can go ahead and preallocate
* memory for all plugged memory blocks, before actual RAM migration starts
* touching this memory.
*/
ret = virtio_mem_for_each_plugged_range(vmem, NULL,
virtio_mem_prealloc_range_cb);
if (ret) {
return ret;
}
/*
* This is tricky: postcopy wants to start with a clean slate. On
* POSTCOPY_INCOMING_ADVISE, postcopy code discards all (ordinarily
* preallocated) RAM such that postcopy will work as expected later.
*
* However, we run after POSTCOPY_INCOMING_ADVISE -- but before actual
* RAM migration. So let's discard all memory again. This looks like an
* expensive NOP, but actually serves a purpose: we made sure that we
* were able to allocate all required backend memory once. We cannot
* guarantee that the backend memory we will free will remain free
* until we need it during postcopy, but at least we can catch the
* obvious setup issues this way.
*/
if (migration_incoming_postcopy_advised()) {
if (ram_block_discard_range(rb, 0, qemu_ram_get_used_length(rb))) {
return -EBUSY;
}
}
post_load_bitmap:
/* Finally, update any other state to be consistent with the new bitmap. */
return virtio_mem_post_load_bitmap(vmem);
}
typedef struct VirtIOMEMMigSanityChecks {
VirtIOMEM *parent;
uint64_t addr;
uint64_t region_size;
uint64_t block_size;
uint32_t node;
} VirtIOMEMMigSanityChecks;
static int virtio_mem_mig_sanity_checks_pre_save(void *opaque)
{
VirtIOMEMMigSanityChecks *tmp = opaque;
VirtIOMEM *vmem = tmp->parent;
tmp->addr = vmem->addr;
tmp->region_size = memory_region_size(&vmem->memdev->mr);
tmp->block_size = vmem->block_size;
tmp->node = vmem->node;
return 0;
}
static int virtio_mem_mig_sanity_checks_post_load(void *opaque, int version_id)
{
VirtIOMEMMigSanityChecks *tmp = opaque;
VirtIOMEM *vmem = tmp->parent;
const uint64_t new_region_size = memory_region_size(&vmem->memdev->mr);
if (tmp->addr != vmem->addr) {
error_report("Property '%s' changed from 0x%" PRIx64 " to 0x%" PRIx64,
VIRTIO_MEM_ADDR_PROP, tmp->addr, vmem->addr);
return -EINVAL;
}
/*
* Note: Preparation for resizable memory regions. The maximum size
* of the memory region must not change during migration.
*/
if (tmp->region_size != new_region_size) {
error_report("Property '%s' size changed from 0x%" PRIx64 " to 0x%"
PRIx64, VIRTIO_MEM_MEMDEV_PROP, tmp->region_size,
new_region_size);
return -EINVAL;
}
if (tmp->block_size != vmem->block_size) {
error_report("Property '%s' changed from 0x%" PRIx64 " to 0x%" PRIx64,
VIRTIO_MEM_BLOCK_SIZE_PROP, tmp->block_size,
vmem->block_size);
return -EINVAL;
}
if (tmp->node != vmem->node) {
error_report("Property '%s' changed from %" PRIu32 " to %" PRIu32,
VIRTIO_MEM_NODE_PROP, tmp->node, vmem->node);
return -EINVAL;
}
return 0;
}
static const VMStateDescription vmstate_virtio_mem_sanity_checks = {
.name = "virtio-mem-device/sanity-checks",
.pre_save = virtio_mem_mig_sanity_checks_pre_save,
.post_load = virtio_mem_mig_sanity_checks_post_load,
.fields = (VMStateField[]) {
VMSTATE_UINT64(addr, VirtIOMEMMigSanityChecks),
VMSTATE_UINT64(region_size, VirtIOMEMMigSanityChecks),
VMSTATE_UINT64(block_size, VirtIOMEMMigSanityChecks),
VMSTATE_UINT32(node, VirtIOMEMMigSanityChecks),
VMSTATE_END_OF_LIST(),
},
};
static bool virtio_mem_vmstate_field_exists(void *opaque, int version_id)
{
const VirtIOMEM *vmem = VIRTIO_MEM(opaque);
/* With early migration, these fields were already migrated. */
return !vmem->early_migration;
}
static const VMStateDescription vmstate_virtio_mem_device = {
.name = "virtio-mem-device",
.minimum_version_id = 1,
.version_id = 1,
.priority = MIG_PRI_VIRTIO_MEM,
.post_load = virtio_mem_post_load,
.fields = (VMStateField[]) {
VMSTATE_WITH_TMP_TEST(VirtIOMEM, virtio_mem_vmstate_field_exists,
VirtIOMEMMigSanityChecks,
vmstate_virtio_mem_sanity_checks),
VMSTATE_UINT64(usable_region_size, VirtIOMEM),
VMSTATE_UINT64_TEST(size, VirtIOMEM, virtio_mem_vmstate_field_exists),
VMSTATE_UINT64(requested_size, VirtIOMEM),
VMSTATE_BITMAP_TEST(bitmap, VirtIOMEM, virtio_mem_vmstate_field_exists,
0, bitmap_size),
VMSTATE_END_OF_LIST()
},
};
/*
* Transfer properties that are immutable while migration is active early,
* such that we have have this information around before migrating any RAM
* content.
*
* Note that virtio_mem_is_busy() makes sure these properties can no longer
* change on the migration source until migration completed.
*
* With QEMU compat machines, we transmit these properties later, via
* vmstate_virtio_mem_device instead -- see virtio_mem_vmstate_field_exists().
*/
static const VMStateDescription vmstate_virtio_mem_device_early = {
.name = "virtio-mem-device-early",
.minimum_version_id = 1,
.version_id = 1,
.early_setup = true,
.post_load = virtio_mem_post_load_early,
.fields = (VMStateField[]) {
VMSTATE_WITH_TMP(VirtIOMEM, VirtIOMEMMigSanityChecks,
vmstate_virtio_mem_sanity_checks),
VMSTATE_UINT64(size, VirtIOMEM),
VMSTATE_BITMAP(bitmap, VirtIOMEM, 0, bitmap_size),
VMSTATE_END_OF_LIST()
},
};
static const VMStateDescription vmstate_virtio_mem = {
.name = "virtio-mem",
.minimum_version_id = 1,
.version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_VIRTIO_DEVICE,
VMSTATE_END_OF_LIST()
},
};
static void virtio_mem_fill_device_info(const VirtIOMEM *vmem,
VirtioMEMDeviceInfo *vi)
{
vi->memaddr = vmem->addr;
vi->node = vmem->node;
vi->requested_size = vmem->requested_size;
vi->size = vmem->size;
vi->max_size = memory_region_size(&vmem->memdev->mr);
vi->block_size = vmem->block_size;
vi->memdev = object_get_canonical_path(OBJECT(vmem->memdev));
}
static MemoryRegion *virtio_mem_get_memory_region(VirtIOMEM *vmem, Error **errp)
{
if (!vmem->memdev) {
error_setg(errp, "'%s' property must be set", VIRTIO_MEM_MEMDEV_PROP);
return NULL;
} else if (vmem->dynamic_memslots) {
if (!vmem->mr) {
virtio_mem_prepare_mr(vmem);
}
return vmem->mr;
}
return &vmem->memdev->mr;
}
static void virtio_mem_decide_memslots(VirtIOMEM *vmem, unsigned int limit)
{
uint64_t region_size, memslot_size, min_memslot_size;
unsigned int memslots;
RAMBlock *rb;
if (!vmem->dynamic_memslots) {
return;
}
/* We're called exactly once, before realizing the device. */
assert(!vmem->nb_memslots);
/* If realizing the device will fail, just assume a single memslot. */
if (limit <= 1 || !vmem->memdev || !vmem->memdev->mr.ram_block) {
vmem->nb_memslots = 1;
return;
}
rb = vmem->memdev->mr.ram_block;
region_size = memory_region_size(&vmem->memdev->mr);
/*
* Determine the default block size now, to determine the minimum memslot
* size. We want the minimum slot size to be at least the device block size.
*/
if (!vmem->block_size) {
vmem->block_size = virtio_mem_default_block_size(rb);
}
/* If realizing the device will fail, just assume a single memslot. */
if (vmem->block_size < qemu_ram_pagesize(rb) ||
!QEMU_IS_ALIGNED(region_size, vmem->block_size)) {
vmem->nb_memslots = 1;
return;
}
/*
* All memslots except the last one have a reasonable minimum size, and
* and all memslot sizes are aligned to the device block size.
*/
memslot_size = QEMU_ALIGN_UP(region_size / limit, vmem->block_size);
min_memslot_size = MAX(vmem->block_size, VIRTIO_MEM_MIN_MEMSLOT_SIZE);
memslot_size = MAX(memslot_size, min_memslot_size);
memslots = QEMU_ALIGN_UP(region_size, memslot_size) / memslot_size;
if (memslots != 1) {
vmem->memslot_size = memslot_size;
}
vmem->nb_memslots = memslots;
}
static unsigned int virtio_mem_get_memslots(VirtIOMEM *vmem)
{
if (!vmem->dynamic_memslots) {
/* Exactly one static RAM memory region. */
return 1;
}
/* We're called after instructed to make a decision. */
g_assert(vmem->nb_memslots);
return vmem->nb_memslots;
}
static void virtio_mem_add_size_change_notifier(VirtIOMEM *vmem,
Notifier *notifier)
{
notifier_list_add(&vmem->size_change_notifiers, notifier);
}
static void virtio_mem_remove_size_change_notifier(VirtIOMEM *vmem,
Notifier *notifier)
{
notifier_remove(notifier);
}
static void virtio_mem_get_size(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
const VirtIOMEM *vmem = VIRTIO_MEM(obj);
uint64_t value = vmem->size;
visit_type_size(v, name, &value, errp);
}
static void virtio_mem_get_requested_size(Object *obj, Visitor *v,
const char *name, void *opaque,
Error **errp)
{
const VirtIOMEM *vmem = VIRTIO_MEM(obj);
uint64_t value = vmem->requested_size;
visit_type_size(v, name, &value, errp);
}
static void virtio_mem_set_requested_size(Object *obj, Visitor *v,
const char *name, void *opaque,
Error **errp)
{
VirtIOMEM *vmem = VIRTIO_MEM(obj);
uint64_t value;
if (!visit_type_size(v, name, &value, errp)) {
return;
}
/*
* The block size and memory backend are not fixed until the device was
* realized. realize() will verify these properties then.
*/
if (DEVICE(obj)->realized) {
if (!QEMU_IS_ALIGNED(value, vmem->block_size)) {
error_setg(errp, "'%s' has to be multiples of '%s' (0x%" PRIx64
")", name, VIRTIO_MEM_BLOCK_SIZE_PROP,
vmem->block_size);
return;
} else if (value > memory_region_size(&vmem->memdev->mr)) {
error_setg(errp, "'%s' cannot exceed the memory backend size"
"(0x%" PRIx64 ")", name,
memory_region_size(&vmem->memdev->mr));
return;
}
if (value != vmem->requested_size) {
virtio_mem_resize_usable_region(vmem, value, false);
vmem->requested_size = value;
}
/*
* Trigger a config update so the guest gets notified. We trigger
* even if the size didn't change (especially helpful for debugging).
*/
virtio_notify_config(VIRTIO_DEVICE(vmem));
} else {
vmem->requested_size = value;
}
}
static void virtio_mem_get_block_size(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
const VirtIOMEM *vmem = VIRTIO_MEM(obj);
uint64_t value = vmem->block_size;
/*
* If not configured by the user (and we're not realized yet), use the
* default block size we would use with the current memory backend.
*/
if (!value) {
if (vmem->memdev && memory_region_is_ram(&vmem->memdev->mr)) {
value = virtio_mem_default_block_size(vmem->memdev->mr.ram_block);
} else {
value = virtio_mem_thp_size();
}
}
visit_type_size(v, name, &value, errp);
}
static void virtio_mem_set_block_size(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
VirtIOMEM *vmem = VIRTIO_MEM(obj);
uint64_t value;
if (DEVICE(obj)->realized) {
error_setg(errp, "'%s' cannot be changed", name);
return;
}
if (!visit_type_size(v, name, &value, errp)) {
return;
}
if (value < VIRTIO_MEM_MIN_BLOCK_SIZE) {
error_setg(errp, "'%s' property has to be at least 0x%" PRIx32, name,
VIRTIO_MEM_MIN_BLOCK_SIZE);
return;
} else if (!is_power_of_2(value)) {
error_setg(errp, "'%s' property has to be a power of two", name);
return;
}
vmem->block_size = value;
}
static void virtio_mem_instance_init(Object *obj)
{
VirtIOMEM *vmem = VIRTIO_MEM(obj);
notifier_list_init(&vmem->size_change_notifiers);
QLIST_INIT(&vmem->rdl_list);
object_property_add(obj, VIRTIO_MEM_SIZE_PROP, "size", virtio_mem_get_size,
NULL, NULL, NULL);
object_property_add(obj, VIRTIO_MEM_REQUESTED_SIZE_PROP, "size",
virtio_mem_get_requested_size,
virtio_mem_set_requested_size, NULL, NULL);
object_property_add(obj, VIRTIO_MEM_BLOCK_SIZE_PROP, "size",
virtio_mem_get_block_size, virtio_mem_set_block_size,
NULL, NULL);
}
static void virtio_mem_instance_finalize(Object *obj)
{
VirtIOMEM *vmem = VIRTIO_MEM(obj);
/*
* Note: the core already dropped the references on all memory regions
* (it's passed as the owner to memory_region_init_*()) and finalized
* these objects. We can simply free the memory.
*/
g_free(vmem->memslots);
vmem->memslots = NULL;
g_free(vmem->mr);
vmem->mr = NULL;
}
static Property virtio_mem_properties[] = {
DEFINE_PROP_UINT64(VIRTIO_MEM_ADDR_PROP, VirtIOMEM, addr, 0),
DEFINE_PROP_UINT32(VIRTIO_MEM_NODE_PROP, VirtIOMEM, node, 0),
DEFINE_PROP_BOOL(VIRTIO_MEM_PREALLOC_PROP, VirtIOMEM, prealloc, false),
DEFINE_PROP_LINK(VIRTIO_MEM_MEMDEV_PROP, VirtIOMEM, memdev,
TYPE_MEMORY_BACKEND, HostMemoryBackend *),
#if defined(VIRTIO_MEM_HAS_LEGACY_GUESTS)
DEFINE_PROP_ON_OFF_AUTO(VIRTIO_MEM_UNPLUGGED_INACCESSIBLE_PROP, VirtIOMEM,
unplugged_inaccessible, ON_OFF_AUTO_ON),
#endif
DEFINE_PROP_BOOL(VIRTIO_MEM_EARLY_MIGRATION_PROP, VirtIOMEM,
early_migration, true),
DEFINE_PROP_BOOL(VIRTIO_MEM_DYNAMIC_MEMSLOTS_PROP, VirtIOMEM,
dynamic_memslots, false),
DEFINE_PROP_END_OF_LIST(),
};
static uint64_t virtio_mem_rdm_get_min_granularity(const RamDiscardManager *rdm,
const MemoryRegion *mr)
{
const VirtIOMEM *vmem = VIRTIO_MEM(rdm);
g_assert(mr == &vmem->memdev->mr);
return vmem->block_size;
}
static bool virtio_mem_rdm_is_populated(const RamDiscardManager *rdm,
const MemoryRegionSection *s)
{
const VirtIOMEM *vmem = VIRTIO_MEM(rdm);
uint64_t start_gpa = vmem->addr + s->offset_within_region;
uint64_t end_gpa = start_gpa + int128_get64(s->size);
g_assert(s->mr == &vmem->memdev->mr);
start_gpa = QEMU_ALIGN_DOWN(start_gpa, vmem->block_size);
end_gpa = QEMU_ALIGN_UP(end_gpa, vmem->block_size);
if (!virtio_mem_valid_range(vmem, start_gpa, end_gpa - start_gpa)) {
return false;
}
return virtio_mem_is_range_plugged(vmem, start_gpa, end_gpa - start_gpa);
}
struct VirtIOMEMReplayData {
void *fn;
void *opaque;
};
static int virtio_mem_rdm_replay_populated_cb(MemoryRegionSection *s, void *arg)
{
struct VirtIOMEMReplayData *data = arg;
return ((ReplayRamPopulate)data->fn)(s, data->opaque);
}
static int virtio_mem_rdm_replay_populated(const RamDiscardManager *rdm,
MemoryRegionSection *s,
ReplayRamPopulate replay_fn,
void *opaque)
{
const VirtIOMEM *vmem = VIRTIO_MEM(rdm);
struct VirtIOMEMReplayData data = {
.fn = replay_fn,
.opaque = opaque,
};
g_assert(s->mr == &vmem->memdev->mr);
return virtio_mem_for_each_plugged_section(vmem, s, &data,
virtio_mem_rdm_replay_populated_cb);
}
static int virtio_mem_rdm_replay_discarded_cb(MemoryRegionSection *s,
void *arg)
{
struct VirtIOMEMReplayData *data = arg;
((ReplayRamDiscard)data->fn)(s, data->opaque);
return 0;
}
static void virtio_mem_rdm_replay_discarded(const RamDiscardManager *rdm,
MemoryRegionSection *s,
ReplayRamDiscard replay_fn,
void *opaque)
{
const VirtIOMEM *vmem = VIRTIO_MEM(rdm);
struct VirtIOMEMReplayData data = {
.fn = replay_fn,
.opaque = opaque,
};
g_assert(s->mr == &vmem->memdev->mr);
virtio_mem_for_each_unplugged_section(vmem, s, &data,
virtio_mem_rdm_replay_discarded_cb);
}
static void virtio_mem_rdm_register_listener(RamDiscardManager *rdm,
RamDiscardListener *rdl,
MemoryRegionSection *s)
{
VirtIOMEM *vmem = VIRTIO_MEM(rdm);
int ret;
g_assert(s->mr == &vmem->memdev->mr);
rdl->section = memory_region_section_new_copy(s);
QLIST_INSERT_HEAD(&vmem->rdl_list, rdl, next);
ret = virtio_mem_for_each_plugged_section(vmem, rdl->section, rdl,
virtio_mem_notify_populate_cb);
if (ret) {
error_report("%s: Replaying plugged ranges failed: %s", __func__,
strerror(-ret));
}
}
static void virtio_mem_rdm_unregister_listener(RamDiscardManager *rdm,
RamDiscardListener *rdl)
{
VirtIOMEM *vmem = VIRTIO_MEM(rdm);
g_assert(rdl->section->mr == &vmem->memdev->mr);
if (vmem->size) {
if (rdl->double_discard_supported) {
rdl->notify_discard(rdl, rdl->section);
} else {
virtio_mem_for_each_plugged_section(vmem, rdl->section, rdl,
virtio_mem_notify_discard_cb);
}
}
memory_region_section_free_copy(rdl->section);
rdl->section = NULL;
QLIST_REMOVE(rdl, next);
}
static void virtio_mem_unplug_request_check(VirtIOMEM *vmem, Error **errp)
{
if (vmem->unplugged_inaccessible == ON_OFF_AUTO_OFF) {
/*
* We could allow it with a usable region size of 0, but let's just
* not care about that legacy setting.
*/
error_setg(errp, "virtio-mem device cannot get unplugged while"
" '" VIRTIO_MEM_UNPLUGGED_INACCESSIBLE_PROP "' != 'on'");
return;
}
if (vmem->size) {
error_setg(errp, "virtio-mem device cannot get unplugged while"
" '" VIRTIO_MEM_SIZE_PROP "' != '0'");
return;
}
if (vmem->requested_size) {
error_setg(errp, "virtio-mem device cannot get unplugged while"
" '" VIRTIO_MEM_REQUESTED_SIZE_PROP "' != '0'");
return;
}
}
static void virtio_mem_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
VirtIOMEMClass *vmc = VIRTIO_MEM_CLASS(klass);
RamDiscardManagerClass *rdmc = RAM_DISCARD_MANAGER_CLASS(klass);
device_class_set_props(dc, virtio_mem_properties);
dc->vmsd = &vmstate_virtio_mem;
set_bit(DEVICE_CATEGORY_MISC, dc->categories);
vdc->realize = virtio_mem_device_realize;
vdc->unrealize = virtio_mem_device_unrealize;
vdc->get_config = virtio_mem_get_config;
vdc->get_features = virtio_mem_get_features;
vdc->validate_features = virtio_mem_validate_features;
vdc->vmsd = &vmstate_virtio_mem_device;
vmc->fill_device_info = virtio_mem_fill_device_info;
vmc->get_memory_region = virtio_mem_get_memory_region;
vmc->decide_memslots = virtio_mem_decide_memslots;
vmc->get_memslots = virtio_mem_get_memslots;
vmc->add_size_change_notifier = virtio_mem_add_size_change_notifier;
vmc->remove_size_change_notifier = virtio_mem_remove_size_change_notifier;
vmc->unplug_request_check = virtio_mem_unplug_request_check;
rdmc->get_min_granularity = virtio_mem_rdm_get_min_granularity;
rdmc->is_populated = virtio_mem_rdm_is_populated;
rdmc->replay_populated = virtio_mem_rdm_replay_populated;
rdmc->replay_discarded = virtio_mem_rdm_replay_discarded;
rdmc->register_listener = virtio_mem_rdm_register_listener;
rdmc->unregister_listener = virtio_mem_rdm_unregister_listener;
}
static const TypeInfo virtio_mem_info = {
.name = TYPE_VIRTIO_MEM,
.parent = TYPE_VIRTIO_DEVICE,
.instance_size = sizeof(VirtIOMEM),
.instance_init = virtio_mem_instance_init,
.instance_finalize = virtio_mem_instance_finalize,
.class_init = virtio_mem_class_init,
.class_size = sizeof(VirtIOMEMClass),
.interfaces = (InterfaceInfo[]) {
{ TYPE_RAM_DISCARD_MANAGER },
{ }
},
};
static void virtio_register_types(void)
{
type_register_static(&virtio_mem_info);
}
type_init(virtio_register_types)
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