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qemu/hw/vfio/migration.c
Joao Martins 30b9167785 vfio/common: Allow disabling device dirty page tracking 
The property 'x-pre-copy-dirty-page-tracking' allows disabling the whole
tracking of VF pre-copy phase of dirty page tracking, though it means
that it will only be used at the start of the switchover phase.

Add an option that disables the VF dirty page tracking, and fall
back into container-based dirty page tracking. This also allows to
use IOMMU dirty tracking even on VFs with their own dirty
tracker scheme.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
2024-07-23 17:14:53 +02:00

1084 lines
33 KiB
C
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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/misc.h"
#include "migration/savevm.h"
#include "migration/vmstate.h"
#include "migration/qemu-file.h"
#include "migration/register.h"
#include "migration/blocker.h"
#include "qapi/error.h"
#include "qapi/qapi-events-vfio.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_RUNNING_P2P:
return "RUNNING_P2P";
case VFIO_DEVICE_STATE_PRE_COPY:
return "PRE_COPY";
case VFIO_DEVICE_STATE_PRE_COPY_P2P:
return "PRE_COPY_P2P";
default:
return "UNKNOWN STATE";
}
}
static VfioMigrationState
mig_state_to_qapi_state(enum vfio_device_mig_state state)
{
switch (state) {
case VFIO_DEVICE_STATE_STOP:
return QAPI_VFIO_MIGRATION_STATE_STOP;
case VFIO_DEVICE_STATE_RUNNING:
return QAPI_VFIO_MIGRATION_STATE_RUNNING;
case VFIO_DEVICE_STATE_STOP_COPY:
return QAPI_VFIO_MIGRATION_STATE_STOP_COPY;
case VFIO_DEVICE_STATE_RESUMING:
return QAPI_VFIO_MIGRATION_STATE_RESUMING;
case VFIO_DEVICE_STATE_RUNNING_P2P:
return QAPI_VFIO_MIGRATION_STATE_RUNNING_P2P;
case VFIO_DEVICE_STATE_PRE_COPY:
return QAPI_VFIO_MIGRATION_STATE_PRE_COPY;
case VFIO_DEVICE_STATE_PRE_COPY_P2P:
return QAPI_VFIO_MIGRATION_STATE_PRE_COPY_P2P;
default:
g_assert_not_reached();
}
}
static void vfio_migration_send_event(VFIODevice *vbasedev)
{
VFIOMigration *migration = vbasedev->migration;
DeviceState *dev = vbasedev->dev;
g_autofree char *qom_path = NULL;
Object *obj;
if (!vbasedev->migration_events) {
return;
}
g_assert(vbasedev->ops->vfio_get_object);
obj = vbasedev->ops->vfio_get_object(vbasedev);
g_assert(obj);
qom_path = object_get_canonical_path(obj);
qapi_event_send_vfio_migration(
dev->id, qom_path, mig_state_to_qapi_state(migration->device_state));
}
static void vfio_migration_set_device_state(VFIODevice *vbasedev,
enum vfio_device_mig_state state)
{
VFIOMigration *migration = vbasedev->migration;
trace_vfio_migration_set_device_state(vbasedev->name,
mig_state_to_str(state));
migration->device_state = state;
vfio_migration_send_event(vbasedev);
}
static int vfio_migration_set_state(VFIODevice *vbasedev,
enum vfio_device_mig_state new_state,
enum vfio_device_mig_state recover_state,
Error **errp)
{
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;
g_autofree char *error_prefix =
g_strdup_printf("%s: Failed setting device state to %s.",
vbasedev->name, mig_state_to_str(new_state));
trace_vfio_migration_set_state(vbasedev->name, mig_state_to_str(new_state),
mig_state_to_str(recover_state));
if (new_state == migration->device_state) {
return 0;
}
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_setg_errno(errp, errno,
"%s Recover state is ERROR. Resetting device",
error_prefix);
goto reset_device;
}
error_setg_errno(errp, errno,
"%s Setting device in recover state %s",
error_prefix, mig_state_to_str(recover_state));
mig_state->device_state = recover_state;
if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
ret = -errno;
/*
* If setting the device in recover state fails, report
* the error here and propagate the first error.
*/
error_report(
"%s: Failed setting device in recover state, err: %s. Resetting device",
vbasedev->name, strerror(errno));
goto reset_device;
}
vfio_migration_set_device_state(vbasedev, recover_state);
return ret;
}
vfio_migration_set_device_state(vbasedev, 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_setg(errp, "%s: data_fd out of sync", vbasedev->name);
close(mig_state->data_fd);
return -EBADF;
}
migration->data_fd = mig_state->data_fd;
}
return 0;
reset_device:
if (ioctl(vbasedev->fd, VFIO_DEVICE_RESET)) {
hw_error("%s: Failed resetting device, err: %s", vbasedev->name,
strerror(errno));
}
vfio_migration_set_device_state(vbasedev, VFIO_DEVICE_STATE_RUNNING);
return ret;
}
/*
* Some device state transitions require resetting the device if they fail.
* This function sets the device in new_state and resets the device if that
* fails. Reset is done by using ERROR as the recover state.
*/
static int
vfio_migration_set_state_or_reset(VFIODevice *vbasedev,
enum vfio_device_mig_state new_state,
Error **errp)
{
return vfio_migration_set_state(vbasedev, new_state,
VFIO_DEVICE_STATE_ERROR, errp);
}
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,
Error **errp)
{
VFIODevice *vbasedev = opaque;
int ret;
qemu_put_be64(f, VFIO_MIG_FLAG_DEV_CONFIG_STATE);
if (vbasedev->ops && vbasedev->ops->vfio_save_config) {
ret = vbasedev->ops->vfio_save_config(vbasedev, f, errp);
if (ret) {
return ret;
}
}
qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
trace_vfio_save_device_config_state(vbasedev->name);
ret = qemu_file_get_error(f);
if (ret < 0) {
error_setg_errno(errp, -ret, "Failed to save state");
}
return ret;
}
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_prepare(void *opaque, Error **errp)
{
VFIODevice *vbasedev = opaque;
/*
* Snapshot doesn't use postcopy nor background snapshot, so allow snapshot
* even if they are on.
*/
if (runstate_check(RUN_STATE_SAVE_VM)) {
return 0;
}
if (migrate_postcopy_ram()) {
error_setg(
errp, "%s: VFIO migration is not supported with postcopy migration",
vbasedev->name);
return -EOPNOTSUPP;
}
if (migrate_background_snapshot()) {
error_setg(
errp,
"%s: VFIO migration is not supported with background snapshot",
vbasedev->name);
return -EOPNOTSUPP;
}
return 0;
}
static int vfio_save_setup(QEMUFile *f, void *opaque, Error **errp)
{
VFIODevice *vbasedev = opaque;
VFIOMigration *migration = vbasedev->migration;
uint64_t stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
int ret;
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_setg(errp, "%s: Failed to allocate migration data buffer",
vbasedev->name);
return -ENOMEM;
}
if (vfio_precopy_supported(vbasedev)) {
switch (migration->device_state) {
case VFIO_DEVICE_STATE_RUNNING:
ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_PRE_COPY,
VFIO_DEVICE_STATE_RUNNING, errp);
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:
error_setg(errp, "%s: Invalid device state %d", vbasedev->name,
migration->device_state);
return -EINVAL;
}
}
trace_vfio_save_setup(vbasedev->name, migration->data_buffer_size);
qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
ret = qemu_file_get_error(f);
if (ret < 0) {
error_setg_errno(errp, -ret, "%s: save setup failed", vbasedev->name);
}
return ret;
}
static void vfio_save_cleanup(void *opaque)
{
VFIODevice *vbasedev = opaque;
VFIOMigration *migration = vbasedev->migration;
Error *local_err = NULL;
int ret;
/*
* Changing device state from STOP_COPY to STOP can take time. Do it here,
* after migration has completed, so it won't increase downtime.
*/
if (migration->device_state == VFIO_DEVICE_STATE_STOP_COPY) {
ret = vfio_migration_set_state_or_reset(vbasedev,
VFIO_DEVICE_STATE_STOP,
&local_err);
if (ret) {
error_report_err(local_err);
}
}
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 (!vfio_device_state_is_precopy(vbasedev)) {
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 (vfio_device_state_is_precopy(vbasedev)) {
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;
return vfio_device_state_is_precopy(vbasedev);
}
/*
* Note about migration rate limiting: VFIO migration buffer size is currently
* limited to 1MB, so there is no need to check if migration rate exceeded (as
* in the worst case it will exceed by 1MB). However, if the buffer size is
* later changed to a bigger value, migration rate should be enforced here.
*/
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);
return !migration->precopy_init_size && !migration->precopy_dirty_size;
}
static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
{
VFIODevice *vbasedev = opaque;
ssize_t data_size;
int ret;
Error *local_err = NULL;
/* 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, &local_err);
if (ret) {
error_report_err(local_err);
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);
trace_vfio_save_complete_precopy(vbasedev->name, ret);
return ret;
}
static void vfio_save_state(QEMUFile *f, void *opaque)
{
VFIODevice *vbasedev = opaque;
Error *local_err = NULL;
int ret;
ret = vfio_save_device_config_state(f, opaque, &local_err);
if (ret) {
error_prepend(&local_err,
"vfio: Failed to save device config space of %s - ",
vbasedev->name);
qemu_file_set_error_obj(f, ret, local_err);
}
}
static int vfio_load_setup(QEMUFile *f, void *opaque, Error **errp)
{
VFIODevice *vbasedev = opaque;
return vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING,
vbasedev->migration->device_state, errp);
}
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_prepare = vfio_save_prepare,
.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_prepare(void *opaque, bool running,
RunState state)
{
VFIODevice *vbasedev = opaque;
VFIOMigration *migration = vbasedev->migration;
enum vfio_device_mig_state new_state;
Error *local_err = NULL;
int ret;
new_state = migration->device_state == VFIO_DEVICE_STATE_PRE_COPY ?
VFIO_DEVICE_STATE_PRE_COPY_P2P :
VFIO_DEVICE_STATE_RUNNING_P2P;
ret = vfio_migration_set_state_or_reset(vbasedev, new_state, &local_err);
if (ret) {
/*
* Migration should be aborted in this case, but vm_state_notify()
* currently does not support reporting failures.
*/
migration_file_set_error(ret, local_err);
}
trace_vfio_vmstate_change_prepare(vbasedev->name, running,
RunState_str(state),
mig_state_to_str(new_state));
}
static void vfio_vmstate_change(void *opaque, bool running, RunState state)
{
VFIODevice *vbasedev = opaque;
enum vfio_device_mig_state new_state;
Error *local_err = NULL;
int ret;
if (running) {
new_state = VFIO_DEVICE_STATE_RUNNING;
} else {
new_state =
(vfio_device_state_is_precopy(vbasedev) &&
(state == RUN_STATE_FINISH_MIGRATE || state == RUN_STATE_PAUSED)) ?
VFIO_DEVICE_STATE_STOP_COPY :
VFIO_DEVICE_STATE_STOP;
}
ret = vfio_migration_set_state_or_reset(vbasedev, new_state, &local_err);
if (ret) {
/*
* Migration should be aborted in this case, but vm_state_notify()
* currently does not support reporting failures.
*/
migration_file_set_error(ret, local_err);
}
trace_vfio_vmstate_change(vbasedev->name, running, RunState_str(state),
mig_state_to_str(new_state));
}
static int vfio_migration_state_notifier(NotifierWithReturn *notifier,
MigrationEvent *e, Error **errp)
{
VFIOMigration *migration = container_of(notifier, VFIOMigration,
migration_state);
VFIODevice *vbasedev = migration->vbasedev;
Error *local_err = NULL;
int ret;
trace_vfio_migration_state_notifier(vbasedev->name, e->type);
if (e->type == MIG_EVENT_PRECOPY_FAILED) {
/*
* MigrationNotifyFunc may not return an error code and an Error
* object for MIG_EVENT_PRECOPY_FAILED. Hence, report the error
* locally and ignore the errp argument.
*/
ret = vfio_migration_set_state_or_reset(vbasedev,
VFIO_DEVICE_STATE_RUNNING,
&local_err);
if (ret) {
error_report_err(local_err);
}
}
return 0;
}
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)) {
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;
VMChangeStateHandler *prepare_cb;
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);
prepare_cb = migration->mig_flags & VFIO_MIGRATION_P2P ?
vfio_vmstate_change_prepare :
NULL;
migration->vm_state = qdev_add_vm_change_state_handler_full(
vbasedev->dev, vfio_vmstate_change, prepare_cb, vbasedev);
migration_add_notifier(&migration->migration_state,
vfio_migration_state_notifier);
return 0;
}
static void vfio_migration_deinit(VFIODevice *vbasedev)
{
VFIOMigration *migration = vbasedev->migration;
migration_remove_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();
}
static int vfio_block_migration(VFIODevice *vbasedev, Error *err, Error **errp)
{
if (vbasedev->enable_migration == ON_OFF_AUTO_ON) {
error_propagate(errp, err);
return -EINVAL;
}
vbasedev->migration_blocker = error_copy(err);
error_free(err);
return migrate_add_blocker_normal(&vbasedev->migration_blocker, errp);
}
/* ---------------------------------------------------------------------- */
int64_t vfio_mig_bytes_transferred(void)
{
return bytes_transferred;
}
void vfio_reset_bytes_transferred(void)
{
bytes_transferred = 0;
}
/*
* Return true when either migration initialized or blocker registered.
* Currently only return false when adding blocker fails which will
* de-register vfio device.
*/
bool vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
{
Error *err = NULL;
int ret;
if (vbasedev->enable_migration == ON_OFF_AUTO_OFF) {
error_setg(&err, "%s: Migration is disabled for VFIO device",
vbasedev->name);
return !vfio_block_migration(vbasedev, err, errp);
}
ret = vfio_migration_init(vbasedev);
if (ret) {
if (ret == -ENOTTY) {
error_setg(&err, "%s: VFIO migration is not supported in kernel",
vbasedev->name);
} else {
error_setg(&err,
"%s: Migration couldn't be initialized for VFIO device, "
"err: %d (%s)",
vbasedev->name, ret, strerror(-ret));
}
return !vfio_block_migration(vbasedev, err, errp);
}
if ((!vbasedev->dirty_pages_supported ||
vbasedev->device_dirty_page_tracking == ON_OFF_AUTO_OFF) &&
!vbasedev->iommu_dirty_tracking) {
if (vbasedev->enable_migration == ON_OFF_AUTO_AUTO) {
error_setg(&err,
"%s: VFIO device doesn't support device and "
"IOMMU dirty tracking", vbasedev->name);
goto add_blocker;
}
warn_report("%s: VFIO device doesn't support device and "
"IOMMU dirty tracking", vbasedev->name);
}
ret = vfio_block_multiple_devices_migration(vbasedev, errp);
if (ret) {
goto out_deinit;
}
if (vfio_viommu_preset(vbasedev)) {
error_setg(&err, "%s: Migration is currently not supported "
"with vIOMMU enabled", vbasedev->name);
goto add_blocker;
}
trace_vfio_migration_realize(vbasedev->name);
return true;
add_blocker:
ret = vfio_block_migration(vbasedev, err, errp);
out_deinit:
if (ret) {
vfio_migration_deinit(vbasedev);
}
return !ret;
}
void vfio_migration_exit(VFIODevice *vbasedev)
{
if (vbasedev->migration) {
vfio_migration_deinit(vbasedev);
}
migrate_del_blocker(&vbasedev->migration_blocker);
}
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