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745c42912a
qemu/hw/vfio/migration.c
Avihai Horon 745c42912a vfio/migration: Add support for switchover ack capability 
Loading of a VFIO device's data can take a substantial amount of time as
the device may need to allocate resources, prepare internal data
structures, etc. This can increase migration downtime, especially for
VFIO devices with a lot of resources.

To solve this, VFIO migration uAPI defines "initial bytes" as part of
its precopy data stream. Initial bytes can be used in various ways to
improve VFIO migration performance. For example, it can be used to
transfer device metadata to pre-allocate resources in the destination.
However, for this to work we need to make sure that all initial bytes
are sent and loaded in the destination before the source VM is stopped.

Use migration switchover ack capability to make sure a VFIO device's
initial bytes are sent and loaded in the destination before the source
stops the VM and attempts to complete the migration.
This can significantly reduce migration downtime for some devices.

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Tested-by: YangHang Liu <yanghliu@redhat.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-06-30 06:02:51 +02:00

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/*
* Migration support for VFIO devices
*
* Copyright NVIDIA, Inc. 2020
*
* 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/main-loop.h"
#include "qemu/cutils.h"
#include "qemu/units.h"
#include "qemu/error-report.h"
#include <linux/vfio.h>
#include <sys/ioctl.h>
#include "sysemu/runstate.h"
#include "hw/vfio/vfio-common.h"
#include "migration/migration.h"
#include "migration/options.h"
#include "migration/savevm.h"
#include "migration/vmstate.h"
#include "migration/qemu-file.h"
#include "migration/register.h"
#include "migration/blocker.h"
#include "migration/misc.h"
#include "qapi/error.h"
#include "exec/ramlist.h"
#include "exec/ram_addr.h"
#include "pci.h"
#include "trace.h"
#include "hw/hw.h"
/*
* Flags to be used as unique delimiters for VFIO devices in the migration
* stream. These flags are composed as:
* 0xffffffff => MSB 32-bit all 1s
* 0xef10 => Magic ID, represents emulated (virtual) function IO
* 0x0000 => 16-bits reserved for flags
*
* The beginning of state information is marked by _DEV_CONFIG_STATE,
* _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a
* certain state information is marked by _END_OF_STATE.
*/
#define VFIO_MIG_FLAG_END_OF_STATE (0xffffffffef100001ULL)
#define VFIO_MIG_FLAG_DEV_CONFIG_STATE (0xffffffffef100002ULL)
#define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xffffffffef100003ULL)
#define VFIO_MIG_FLAG_DEV_DATA_STATE (0xffffffffef100004ULL)
#define VFIO_MIG_FLAG_DEV_INIT_DATA_SENT (0xffffffffef100005ULL)
/*
* This is an arbitrary size based on migration of mlx5 devices, where typically
* total device migration size is on the order of 100s of MB. Testing with
* larger values, e.g. 128MB and 1GB, did not show a performance improvement.
*/
#define VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE (1 * MiB)
static int64_t bytes_transferred;
static const char *mig_state_to_str(enum vfio_device_mig_state state)
{
switch (state) {
case VFIO_DEVICE_STATE_ERROR:
return "ERROR";
case VFIO_DEVICE_STATE_STOP:
return "STOP";
case VFIO_DEVICE_STATE_RUNNING:
return "RUNNING";
case VFIO_DEVICE_STATE_STOP_COPY:
return "STOP_COPY";
case VFIO_DEVICE_STATE_RESUMING:
return "RESUMING";
case VFIO_DEVICE_STATE_PRE_COPY:
return "PRE_COPY";
default:
return "UNKNOWN STATE";
}
}
static int vfio_migration_set_state(VFIODevice *vbasedev,
enum vfio_device_mig_state new_state,
enum vfio_device_mig_state recover_state)
{
VFIOMigration *migration = vbasedev->migration;
uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
sizeof(struct vfio_device_feature_mig_state),
sizeof(uint64_t))] = {};
struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
struct vfio_device_feature_mig_state *mig_state =
(struct vfio_device_feature_mig_state *)feature->data;
int ret;
feature->argsz = sizeof(buf);
feature->flags =
VFIO_DEVICE_FEATURE_SET | VFIO_DEVICE_FEATURE_MIG_DEVICE_STATE;
mig_state->device_state = new_state;
if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
/* Try to set the device in some good state */
ret = -errno;
if (recover_state == VFIO_DEVICE_STATE_ERROR) {
error_report("%s: Failed setting device state to %s, err: %s. "
"Recover state is ERROR. Resetting device",
vbasedev->name, mig_state_to_str(new_state),
strerror(errno));
goto reset_device;
}
error_report(
"%s: Failed setting device state to %s, err: %s. Setting device in recover state %s",
vbasedev->name, mig_state_to_str(new_state),
strerror(errno), mig_state_to_str(recover_state));
mig_state->device_state = recover_state;
if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
ret = -errno;
error_report(
"%s: Failed setting device in recover state, err: %s. Resetting device",
vbasedev->name, strerror(errno));
goto reset_device;
}
migration->device_state = recover_state;
return ret;
}
migration->device_state = new_state;
if (mig_state->data_fd != -1) {
if (migration->data_fd != -1) {
/*
* This can happen if the device is asynchronously reset and
* terminates a data transfer.
*/
error_report("%s: data_fd out of sync", vbasedev->name);
close(mig_state->data_fd);
return -EBADF;
}
migration->data_fd = mig_state->data_fd;
}
trace_vfio_migration_set_state(vbasedev->name, mig_state_to_str(new_state));
return 0;
reset_device:
if (ioctl(vbasedev->fd, VFIO_DEVICE_RESET)) {
hw_error("%s: Failed resetting device, err: %s", vbasedev->name,
strerror(errno));
}
migration->device_state = VFIO_DEVICE_STATE_RUNNING;
return ret;
}
static int vfio_load_buffer(QEMUFile *f, VFIODevice *vbasedev,
uint64_t data_size)
{
VFIOMigration *migration = vbasedev->migration;
int ret;
ret = qemu_file_get_to_fd(f, migration->data_fd, data_size);
trace_vfio_load_state_device_data(vbasedev->name, data_size, ret);
return ret;
}
static int vfio_save_device_config_state(QEMUFile *f, void *opaque)
{
VFIODevice *vbasedev = opaque;
qemu_put_be64(f, VFIO_MIG_FLAG_DEV_CONFIG_STATE);
if (vbasedev->ops && vbasedev->ops->vfio_save_config) {
vbasedev->ops->vfio_save_config(vbasedev, f);
}
qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
trace_vfio_save_device_config_state(vbasedev->name);
return qemu_file_get_error(f);
}
static int vfio_load_device_config_state(QEMUFile *f, void *opaque)
{
VFIODevice *vbasedev = opaque;
uint64_t data;
if (vbasedev->ops && vbasedev->ops->vfio_load_config) {
int ret;
ret = vbasedev->ops->vfio_load_config(vbasedev, f);
if (ret) {
error_report("%s: Failed to load device config space",
vbasedev->name);
return ret;
}
}
data = qemu_get_be64(f);
if (data != VFIO_MIG_FLAG_END_OF_STATE) {
error_report("%s: Failed loading device config space, "
"end flag incorrect 0x%"PRIx64, vbasedev->name, data);
return -EINVAL;
}
trace_vfio_load_device_config_state(vbasedev->name);
return qemu_file_get_error(f);
}
static void vfio_migration_cleanup(VFIODevice *vbasedev)
{
VFIOMigration *migration = vbasedev->migration;
close(migration->data_fd);
migration->data_fd = -1;
}
static int vfio_query_stop_copy_size(VFIODevice *vbasedev,
uint64_t *stop_copy_size)
{
uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
sizeof(struct vfio_device_feature_mig_data_size),
sizeof(uint64_t))] = {};
struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
struct vfio_device_feature_mig_data_size *mig_data_size =
(struct vfio_device_feature_mig_data_size *)feature->data;
feature->argsz = sizeof(buf);
feature->flags =
VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_MIG_DATA_SIZE;
if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
return -errno;
}
*stop_copy_size = mig_data_size->stop_copy_length;
return 0;
}
static int vfio_query_precopy_size(VFIOMigration *migration)
{
struct vfio_precopy_info precopy = {
.argsz = sizeof(precopy),
};
migration->precopy_init_size = 0;
migration->precopy_dirty_size = 0;
if (ioctl(migration->data_fd, VFIO_MIG_GET_PRECOPY_INFO, &precopy)) {
return -errno;
}
migration->precopy_init_size = precopy.initial_bytes;
migration->precopy_dirty_size = precopy.dirty_bytes;
return 0;
}
/* Returns the size of saved data on success and -errno on error */
static ssize_t vfio_save_block(QEMUFile *f, VFIOMigration *migration)
{
ssize_t data_size;
data_size = read(migration->data_fd, migration->data_buffer,
migration->data_buffer_size);
if (data_size < 0) {
/*
* Pre-copy emptied all the device state for now. For more information,
* please refer to the Linux kernel VFIO uAPI.
*/
if (errno == ENOMSG) {
return 0;
}
return -errno;
}
if (data_size == 0) {
return 0;
}
qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE);
qemu_put_be64(f, data_size);
qemu_put_buffer(f, migration->data_buffer, data_size);
bytes_transferred += data_size;
trace_vfio_save_block(migration->vbasedev->name, data_size);
return qemu_file_get_error(f) ?: data_size;
}
static void vfio_update_estimated_pending_data(VFIOMigration *migration,
uint64_t data_size)
{
if (!data_size) {
/*
* Pre-copy emptied all the device state for now, update estimated sizes
* accordingly.
*/
migration->precopy_init_size = 0;
migration->precopy_dirty_size = 0;
return;
}
if (migration->precopy_init_size) {
uint64_t init_size = MIN(migration->precopy_init_size, data_size);
migration->precopy_init_size -= init_size;
data_size -= init_size;
}
migration->precopy_dirty_size -= MIN(migration->precopy_dirty_size,
data_size);
}
static bool vfio_precopy_supported(VFIODevice *vbasedev)
{
VFIOMigration *migration = vbasedev->migration;
return migration->mig_flags & VFIO_MIGRATION_PRE_COPY;
}
/* ---------------------------------------------------------------------- */
static int vfio_save_setup(QEMUFile *f, void *opaque)
{
VFIODevice *vbasedev = opaque;
VFIOMigration *migration = vbasedev->migration;
uint64_t stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
vfio_query_stop_copy_size(vbasedev, &stop_copy_size);
migration->data_buffer_size = MIN(VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE,
stop_copy_size);
migration->data_buffer = g_try_malloc0(migration->data_buffer_size);
if (!migration->data_buffer) {
error_report("%s: Failed to allocate migration data buffer",
vbasedev->name);
return -ENOMEM;
}
if (vfio_precopy_supported(vbasedev)) {
int ret;
switch (migration->device_state) {
case VFIO_DEVICE_STATE_RUNNING:
ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_PRE_COPY,
VFIO_DEVICE_STATE_RUNNING);
if (ret) {
return ret;
}
vfio_query_precopy_size(migration);
break;
case VFIO_DEVICE_STATE_STOP:
/* vfio_save_complete_precopy() will go to STOP_COPY */
break;
default:
return -EINVAL;
}
}
trace_vfio_save_setup(vbasedev->name, migration->data_buffer_size);
qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
return qemu_file_get_error(f);
}
static void vfio_save_cleanup(void *opaque)
{
VFIODevice *vbasedev = opaque;
VFIOMigration *migration = vbasedev->migration;
g_free(migration->data_buffer);
migration->data_buffer = NULL;
migration->precopy_init_size = 0;
migration->precopy_dirty_size = 0;
migration->initial_data_sent = false;
vfio_migration_cleanup(vbasedev);
trace_vfio_save_cleanup(vbasedev->name);
}
static void vfio_state_pending_estimate(void *opaque, uint64_t *must_precopy,
uint64_t *can_postcopy)
{
VFIODevice *vbasedev = opaque;
VFIOMigration *migration = vbasedev->migration;
if (migration->device_state != VFIO_DEVICE_STATE_PRE_COPY) {
return;
}
*must_precopy +=
migration->precopy_init_size + migration->precopy_dirty_size;
trace_vfio_state_pending_estimate(vbasedev->name, *must_precopy,
*can_postcopy,
migration->precopy_init_size,
migration->precopy_dirty_size);
}
/*
* Migration size of VFIO devices can be as little as a few KBs or as big as
* many GBs. This value should be big enough to cover the worst case.
*/
#define VFIO_MIG_STOP_COPY_SIZE (100 * GiB)
static void vfio_state_pending_exact(void *opaque, uint64_t *must_precopy,
uint64_t *can_postcopy)
{
VFIODevice *vbasedev = opaque;
VFIOMigration *migration = vbasedev->migration;
uint64_t stop_copy_size = VFIO_MIG_STOP_COPY_SIZE;
/*
* If getting pending migration size fails, VFIO_MIG_STOP_COPY_SIZE is
* reported so downtime limit won't be violated.
*/
vfio_query_stop_copy_size(vbasedev, &stop_copy_size);
*must_precopy += stop_copy_size;
if (migration->device_state == VFIO_DEVICE_STATE_PRE_COPY) {
vfio_query_precopy_size(migration);
*must_precopy +=
migration->precopy_init_size + migration->precopy_dirty_size;
}
trace_vfio_state_pending_exact(vbasedev->name, *must_precopy, *can_postcopy,
stop_copy_size, migration->precopy_init_size,
migration->precopy_dirty_size);
}
static bool vfio_is_active_iterate(void *opaque)
{
VFIODevice *vbasedev = opaque;
VFIOMigration *migration = vbasedev->migration;
return migration->device_state == VFIO_DEVICE_STATE_PRE_COPY;
}
static int vfio_save_iterate(QEMUFile *f, void *opaque)
{
VFIODevice *vbasedev = opaque;
VFIOMigration *migration = vbasedev->migration;
ssize_t data_size;
data_size = vfio_save_block(f, migration);
if (data_size < 0) {
return data_size;
}
vfio_update_estimated_pending_data(migration, data_size);
if (migrate_switchover_ack() && !migration->precopy_init_size &&
!migration->initial_data_sent) {
qemu_put_be64(f, VFIO_MIG_FLAG_DEV_INIT_DATA_SENT);
migration->initial_data_sent = true;
} else {
qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
}
trace_vfio_save_iterate(vbasedev->name, migration->precopy_init_size,
migration->precopy_dirty_size);
/*
* A VFIO device's pre-copy dirty_bytes is not guaranteed to reach zero.
* Return 1 so following handlers will not be potentially blocked.
*/
return 1;
}
static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
{
VFIODevice *vbasedev = opaque;
ssize_t data_size;
int ret;
/* We reach here with device state STOP or STOP_COPY only */
ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP_COPY,
VFIO_DEVICE_STATE_STOP);
if (ret) {
return ret;
}
do {
data_size = vfio_save_block(f, vbasedev->migration);
if (data_size < 0) {
return data_size;
}
} while (data_size);
qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
ret = qemu_file_get_error(f);
if (ret) {
return ret;
}
/*
* If setting the device in STOP state fails, the device should be reset.
* To do so, use ERROR state as a recover state.
*/
ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP,
VFIO_DEVICE_STATE_ERROR);
trace_vfio_save_complete_precopy(vbasedev->name, ret);
return ret;
}
static void vfio_save_state(QEMUFile *f, void *opaque)
{
VFIODevice *vbasedev = opaque;
int ret;
ret = vfio_save_device_config_state(f, opaque);
if (ret) {
error_report("%s: Failed to save device config space",
vbasedev->name);
qemu_file_set_error(f, ret);
}
}
static int vfio_load_setup(QEMUFile *f, void *opaque)
{
VFIODevice *vbasedev = opaque;
return vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING,
vbasedev->migration->device_state);
}
static int vfio_load_cleanup(void *opaque)
{
VFIODevice *vbasedev = opaque;
vfio_migration_cleanup(vbasedev);
trace_vfio_load_cleanup(vbasedev->name);
return 0;
}
static int vfio_load_state(QEMUFile *f, void *opaque, int version_id)
{
VFIODevice *vbasedev = opaque;
int ret = 0;
uint64_t data;
data = qemu_get_be64(f);
while (data != VFIO_MIG_FLAG_END_OF_STATE) {
trace_vfio_load_state(vbasedev->name, data);
switch (data) {
case VFIO_MIG_FLAG_DEV_CONFIG_STATE:
{
return vfio_load_device_config_state(f, opaque);
}
case VFIO_MIG_FLAG_DEV_SETUP_STATE:
{
data = qemu_get_be64(f);
if (data == VFIO_MIG_FLAG_END_OF_STATE) {
return ret;
} else {
error_report("%s: SETUP STATE: EOS not found 0x%"PRIx64,
vbasedev->name, data);
return -EINVAL;
}
break;
}
case VFIO_MIG_FLAG_DEV_DATA_STATE:
{
uint64_t data_size = qemu_get_be64(f);
if (data_size) {
ret = vfio_load_buffer(f, vbasedev, data_size);
if (ret < 0) {
return ret;
}
}
break;
}
case VFIO_MIG_FLAG_DEV_INIT_DATA_SENT:
{
if (!vfio_precopy_supported(vbasedev) ||
!migrate_switchover_ack()) {
error_report("%s: Received INIT_DATA_SENT but switchover ack "
"is not used", vbasedev->name);
return -EINVAL;
}
ret = qemu_loadvm_approve_switchover();
if (ret) {
error_report(
"%s: qemu_loadvm_approve_switchover failed, err=%d (%s)",
vbasedev->name, ret, strerror(-ret));
}
return ret;
}
default:
error_report("%s: Unknown tag 0x%"PRIx64, vbasedev->name, data);
return -EINVAL;
}
data = qemu_get_be64(f);
ret = qemu_file_get_error(f);
if (ret) {
return ret;
}
}
return ret;
}
static bool vfio_switchover_ack_needed(void *opaque)
{
VFIODevice *vbasedev = opaque;
return vfio_precopy_supported(vbasedev);
}
static const SaveVMHandlers savevm_vfio_handlers = {
.save_setup = vfio_save_setup,
.save_cleanup = vfio_save_cleanup,
.state_pending_estimate = vfio_state_pending_estimate,
.state_pending_exact = vfio_state_pending_exact,
.is_active_iterate = vfio_is_active_iterate,
.save_live_iterate = vfio_save_iterate,
.save_live_complete_precopy = vfio_save_complete_precopy,
.save_state = vfio_save_state,
.load_setup = vfio_load_setup,
.load_cleanup = vfio_load_cleanup,
.load_state = vfio_load_state,
.switchover_ack_needed = vfio_switchover_ack_needed,
};
/* ---------------------------------------------------------------------- */
static void vfio_vmstate_change(void *opaque, bool running, RunState state)
{
VFIODevice *vbasedev = opaque;
VFIOMigration *migration = vbasedev->migration;
enum vfio_device_mig_state new_state;
int ret;
if (running) {
new_state = VFIO_DEVICE_STATE_RUNNING;
} else {
new_state =
(migration->device_state == VFIO_DEVICE_STATE_PRE_COPY &&
(state == RUN_STATE_FINISH_MIGRATE || state == RUN_STATE_PAUSED)) ?
VFIO_DEVICE_STATE_STOP_COPY :
VFIO_DEVICE_STATE_STOP;
}
/*
* If setting the device in new_state fails, the device should be reset.
* To do so, use ERROR state as a recover state.
*/
ret = vfio_migration_set_state(vbasedev, new_state,
VFIO_DEVICE_STATE_ERROR);
if (ret) {
/*
* Migration should be aborted in this case, but vm_state_notify()
* currently does not support reporting failures.
*/
if (migrate_get_current()->to_dst_file) {
qemu_file_set_error(migrate_get_current()->to_dst_file, ret);
}
}
trace_vfio_vmstate_change(vbasedev->name, running, RunState_str(state),
mig_state_to_str(new_state));
}
static void vfio_migration_state_notifier(Notifier *notifier, void *data)
{
MigrationState *s = data;
VFIOMigration *migration = container_of(notifier, VFIOMigration,
migration_state);
VFIODevice *vbasedev = migration->vbasedev;
trace_vfio_migration_state_notifier(vbasedev->name,
MigrationStatus_str(s->state));
switch (s->state) {
case MIGRATION_STATUS_CANCELLING:
case MIGRATION_STATUS_CANCELLED:
case MIGRATION_STATUS_FAILED:
bytes_transferred = 0;
/*
* If setting the device in RUNNING state fails, the device should
* be reset. To do so, use ERROR state as a recover state.
*/
vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RUNNING,
VFIO_DEVICE_STATE_ERROR);
}
}
static void vfio_migration_free(VFIODevice *vbasedev)
{
g_free(vbasedev->migration);
vbasedev->migration = NULL;
}
static int vfio_migration_query_flags(VFIODevice *vbasedev, uint64_t *mig_flags)
{
uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
sizeof(struct vfio_device_feature_migration),
sizeof(uint64_t))] = {};
struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
struct vfio_device_feature_migration *mig =
(struct vfio_device_feature_migration *)feature->data;
feature->argsz = sizeof(buf);
feature->flags = VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_MIGRATION;
if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
if (errno == ENOTTY) {
error_report("%s: VFIO migration is not supported in kernel",
vbasedev->name);
} else {
error_report("%s: Failed to query VFIO migration support, err: %s",
vbasedev->name, strerror(errno));
}
return -errno;
}
*mig_flags = mig->flags;
return 0;
}
static bool vfio_dma_logging_supported(VFIODevice *vbasedev)
{
uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature),
sizeof(uint64_t))] = {};
struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
feature->argsz = sizeof(buf);
feature->flags = VFIO_DEVICE_FEATURE_PROBE |
VFIO_DEVICE_FEATURE_DMA_LOGGING_START;
return !ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature);
}
static int vfio_migration_init(VFIODevice *vbasedev)
{
int ret;
Object *obj;
VFIOMigration *migration;
char id[256] = "";
g_autofree char *path = NULL, *oid = NULL;
uint64_t mig_flags = 0;
if (!vbasedev->ops->vfio_get_object) {
return -EINVAL;
}
obj = vbasedev->ops->vfio_get_object(vbasedev);
if (!obj) {
return -EINVAL;
}
ret = vfio_migration_query_flags(vbasedev, &mig_flags);
if (ret) {
return ret;
}
/* Basic migration functionality must be supported */
if (!(mig_flags & VFIO_MIGRATION_STOP_COPY)) {
return -EOPNOTSUPP;
}
vbasedev->migration = g_new0(VFIOMigration, 1);
migration = vbasedev->migration;
migration->vbasedev = vbasedev;
migration->device_state = VFIO_DEVICE_STATE_RUNNING;
migration->data_fd = -1;
migration->mig_flags = mig_flags;
vbasedev->dirty_pages_supported = vfio_dma_logging_supported(vbasedev);
oid = vmstate_if_get_id(VMSTATE_IF(DEVICE(obj)));
if (oid) {
path = g_strdup_printf("%s/vfio", oid);
} else {
path = g_strdup("vfio");
}
strpadcpy(id, sizeof(id), path, '\0');
register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1, &savevm_vfio_handlers,
vbasedev);
migration->vm_state = qdev_add_vm_change_state_handler(vbasedev->dev,
vfio_vmstate_change,
vbasedev);
migration->migration_state.notify = vfio_migration_state_notifier;
add_migration_state_change_notifier(&migration->migration_state);
return 0;
}
/* ---------------------------------------------------------------------- */
int64_t vfio_mig_bytes_transferred(void)
{
return bytes_transferred;
}
int vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
{
int ret = -ENOTSUP;
if (!vbasedev->enable_migration) {
goto add_blocker;
}
ret = vfio_migration_init(vbasedev);
if (ret) {
goto add_blocker;
}
ret = vfio_block_multiple_devices_migration(errp);
if (ret) {
return ret;
}
ret = vfio_block_giommu_migration(errp);
if (ret) {
return ret;
}
trace_vfio_migration_probe(vbasedev->name);
return 0;
add_blocker:
error_setg(&vbasedev->migration_blocker,
"VFIO device doesn't support migration");
ret = migrate_add_blocker(vbasedev->migration_blocker, errp);
if (ret < 0) {
error_free(vbasedev->migration_blocker);
vbasedev->migration_blocker = NULL;
}
return ret;
}
void vfio_migration_exit(VFIODevice *vbasedev)
{
if (vbasedev->migration) {
VFIOMigration *migration = vbasedev->migration;
remove_migration_state_change_notifier(&migration->migration_state);
qemu_del_vm_change_state_handler(migration->vm_state);
unregister_savevm(VMSTATE_IF(vbasedev->dev), "vfio", vbasedev);
vfio_migration_free(vbasedev);
vfio_unblock_multiple_devices_migration();
}
if (vbasedev->migration_blocker) {
migrate_del_blocker(vbasedev->migration_blocker);
error_free(vbasedev->migration_blocker);
vbasedev->migration_blocker = NULL;
}
}
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