vitalif
/
mirror_qemu
mirror of https://github.com/proxmox/mirror_qemu
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
mirror_qemu/hw/vfio/migration.c

691 lines
21 KiB
C
Raw Blame History

/*
* 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/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)
/*
* 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";
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;
}
/* Returns 1 if end-of-stream is reached, 0 if more data and -errno if error */
static int 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) {
return -errno;
}
if (data_size == 0) {
return 1;
}
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);
}
/* ---------------------------------------------------------------------- */
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;
}
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;
vfio_migration_cleanup(vbasedev);
trace_vfio_save_cleanup(vbasedev->name);
}
/*
* 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)
/*
* Only exact function is implemented and not estimate function. The reason is
* that during pre-copy phase of migration the estimate function is called
* repeatedly while pending RAM size is over the threshold, thus migration
* can't converge and querying the VFIO device pending data size is useless.
*/
static void vfio_state_pending_exact(void *opaque, uint64_t *must_precopy,
uint64_t *can_postcopy)
{
VFIODevice *vbasedev = opaque;
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;
trace_vfio_state_pending_exact(vbasedev->name, *must_precopy, *can_postcopy,
stop_copy_size);
}
static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
{
VFIODevice *vbasedev = opaque;
int ret;
/* We reach here with device state STOP only */
ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP_COPY,
VFIO_DEVICE_STATE_STOP);
if (ret) {
return ret;
}
do {
ret = vfio_save_block(f, vbasedev->migration);
if (ret < 0) {
return ret;
}
} while (!ret);
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;
}
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 const SaveVMHandlers savevm_vfio_handlers = {
.save_setup = vfio_save_setup,
.save_cleanup = vfio_save_cleanup,
.state_pending_exact = vfio_state_pending_exact,
.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,
};
/* ---------------------------------------------------------------------- */
static void vfio_vmstate_change(void *opaque, bool running, RunState state)
{
VFIODevice *vbasedev = opaque;
enum vfio_device_mig_state new_state;
int ret;
if (running) {
new_state = VFIO_DEVICE_STATE_RUNNING;
} else {
new_state = 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;
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;
}
}
Reference in New Issue View Git Blame Copy Permalink