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pve-qemu-qoup/debian/patches/pve/0017-PVE-add-savevm-async-for-background-state-snapshots.patch
Fiona Ebner 86460aef76 fix #4507: add patch to automatically increase NOFILE soft limit 
In many configurations, e.g. multiple vNICs with multiple queues or
with many Ceph OSDs, the default soft limit of 1024 is not enough.
QEMU is supposed to work fine with file descriptors >= 1024 and does
not use select() on POSIX. Bump the soft limit to the allowed hard
limit to avoid issues with the aforementioned configurations.

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
2024-02-06 10:33:12 +01:00

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Dietmar Maurer <dietmar@proxmox.com>
Date: Mon, 6 Apr 2020 12:16:46 +0200
Subject: [PATCH] PVE: add savevm-async for background state snapshots
Put qemu_savevm_state_{header,setup} into the main loop and the rest
of the iteration into a coroutine. The former need to lock the
iothread (and we can't unlock it in the coroutine), and the latter
can't deal with being in a separate thread, so a coroutine it must
be.
Truncate output file at 1024 boundary.
Do not block the VM and save the state on aborting a snapshot, as the
snapshot will be invalid anyway.
Also, when aborting, wait for the target file to be closed, otherwise a
client might run into race-conditions when trying to remove the file
still opened by QEMU.
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
Signed-off-by: Dietmar Maurer <dietmar@proxmox.com>
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
[SR: improve aborting
register yank before migration_incoming_state_destroy]
Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
[FE: further improve aborting
adapt to removal of QEMUFileOps
improve condition for entering final stage
adapt to QAPI and other changes for 8.0]
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
hmp-commands-info.hx | 13 +
hmp-commands.hx | 17 ++
include/migration/snapshot.h | 2 +
include/monitor/hmp.h | 3 +
migration/meson.build | 1 +
migration/savevm-async.c | 531 +++++++++++++++++++++++++++++++++++
monitor/hmp-cmds.c | 38 +++
qapi/migration.json | 34 +++
qapi/misc.json | 16 ++
qemu-options.hx | 12 +
softmmu/vl.c | 10 +
11 files changed, 677 insertions(+)
create mode 100644 migration/savevm-async.c
diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
index f5b37eb74a..10fdd822e0 100644
--- a/hmp-commands-info.hx
+++ b/hmp-commands-info.hx
@@ -525,6 +525,19 @@ SRST
Show current migration parameters.
ERST
+ {
+ .name = "savevm",
+ .args_type = "",
+ .params = "",
+ .help = "show savevm status",
+ .cmd = hmp_info_savevm,
+ },
+
+SRST
+ ``info savevm``
+ Show savevm status.
+ERST
+
{
.name = "balloon",
.args_type = "",
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 2cbd0f77a0..e352f86872 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1865,3 +1865,20 @@ SRST
List event channels in the guest
ERST
#endif
+
+ {
+ .name = "savevm-start",
+ .args_type = "statefile:s?",
+ .params = "[statefile]",
+ .help = "Prepare for snapshot and halt VM. Save VM state to statefile.",
+ .cmd = hmp_savevm_start,
+ },
+
+ {
+ .name = "savevm-end",
+ .args_type = "",
+ .params = "",
+ .help = "Resume VM after snaphot.",
+ .cmd = hmp_savevm_end,
+ .coroutine = true,
+ },
diff --git a/include/migration/snapshot.h b/include/migration/snapshot.h
index e72083b117..c846d37806 100644
--- a/include/migration/snapshot.h
+++ b/include/migration/snapshot.h
@@ -61,4 +61,6 @@ bool delete_snapshot(const char *name,
bool has_devices, strList *devices,
Error **errp);
+int load_snapshot_from_blockdev(const char *filename, Error **errp);
+
#endif
diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
index 13f9a2dedb..7a7def7530 100644
--- a/include/monitor/hmp.h
+++ b/include/monitor/hmp.h
@@ -28,6 +28,7 @@ void hmp_info_status(Monitor *mon, const QDict *qdict);
void hmp_info_uuid(Monitor *mon, const QDict *qdict);
void hmp_info_chardev(Monitor *mon, const QDict *qdict);
void hmp_info_mice(Monitor *mon, const QDict *qdict);
+void hmp_info_savevm(Monitor *mon, const QDict *qdict);
void hmp_info_migrate(Monitor *mon, const QDict *qdict);
void hmp_info_migrate_capabilities(Monitor *mon, const QDict *qdict);
void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict);
@@ -94,6 +95,8 @@ void hmp_closefd(Monitor *mon, const QDict *qdict);
void hmp_mouse_move(Monitor *mon, const QDict *qdict);
void hmp_mouse_button(Monitor *mon, const QDict *qdict);
void hmp_mouse_set(Monitor *mon, const QDict *qdict);
+void hmp_savevm_start(Monitor *mon, const QDict *qdict);
+void hmp_savevm_end(Monitor *mon, const QDict *qdict);
void hmp_sendkey(Monitor *mon, const QDict *qdict);
void coroutine_fn hmp_screendump(Monitor *mon, const QDict *qdict);
void hmp_chardev_add(Monitor *mon, const QDict *qdict);
diff --git a/migration/meson.build b/migration/meson.build
index 37ddcb5d60..07f6057acc 100644
--- a/migration/meson.build
+++ b/migration/meson.build
@@ -26,6 +26,7 @@ system_ss.add(files(
'options.c',
'postcopy-ram.c',
'savevm.c',
+ 'savevm-async.c',
'socket.c',
'tls.c',
'threadinfo.c',
diff --git a/migration/savevm-async.c b/migration/savevm-async.c
new file mode 100644
index 0000000000..e9fc18fb10
--- /dev/null
+++ b/migration/savevm-async.c
@@ -0,0 +1,531 @@
+#include "qemu/osdep.h"
+#include "migration/channel-savevm-async.h"
+#include "migration/migration.h"
+#include "migration/migration-stats.h"
+#include "migration/options.h"
+#include "migration/savevm.h"
+#include "migration/snapshot.h"
+#include "migration/global_state.h"
+#include "migration/ram.h"
+#include "migration/qemu-file.h"
+#include "sysemu/sysemu.h"
+#include "sysemu/runstate.h"
+#include "block/block.h"
+#include "sysemu/block-backend.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qerror.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qapi-commands-migration.h"
+#include "qapi/qapi-commands-misc.h"
+#include "qapi/qapi-commands-block.h"
+#include "qemu/cutils.h"
+#include "qemu/timer.h"
+#include "qemu/main-loop.h"
+#include "qemu/rcu.h"
+#include "qemu/yank.h"
+
+/* #define DEBUG_SAVEVM_STATE */
+
+#ifdef DEBUG_SAVEVM_STATE
+#define DPRINTF(fmt, ...) \
+ do { printf("savevm-async: " fmt, ## __VA_ARGS__); } while (0)
+#else
+#define DPRINTF(fmt, ...) \
+ do { } while (0)
+#endif
+
+enum {
+ SAVE_STATE_DONE,
+ SAVE_STATE_ERROR,
+ SAVE_STATE_ACTIVE,
+ SAVE_STATE_COMPLETED,
+ SAVE_STATE_CANCELLED
+};
+
+
+static struct SnapshotState {
+ BlockBackend *target;
+ size_t bs_pos;
+ int state;
+ Error *error;
+ Error *blocker;
+ int saved_vm_running;
+ QEMUFile *file;
+ int64_t total_time;
+ QEMUBH *finalize_bh;
+ Coroutine *co;
+ QemuCoSleep target_close_wait;
+} snap_state;
+
+static bool savevm_aborted(void)
+{
+ return snap_state.state == SAVE_STATE_CANCELLED ||
+ snap_state.state == SAVE_STATE_ERROR;
+}
+
+SaveVMInfo *qmp_query_savevm(Error **errp)
+{
+ SaveVMInfo *info = g_malloc0(sizeof(*info));
+ struct SnapshotState *s = &snap_state;
+
+ if (s->state != SAVE_STATE_DONE) {
+ info->has_bytes = true;
+ info->bytes = s->bs_pos;
+ switch (s->state) {
+ case SAVE_STATE_ERROR:
+ info->status = g_strdup("failed");
+ info->has_total_time = true;
+ info->total_time = s->total_time;
+ if (s->error) {
+ info->error = g_strdup(error_get_pretty(s->error));
+ }
+ break;
+ case SAVE_STATE_ACTIVE:
+ info->status = g_strdup("active");
+ info->has_total_time = true;
+ info->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME)
+ - s->total_time;
+ break;
+ case SAVE_STATE_COMPLETED:
+ info->status = g_strdup("completed");
+ info->has_total_time = true;
+ info->total_time = s->total_time;
+ break;
+ }
+ }
+
+ return info;
+}
+
+static int save_snapshot_cleanup(void)
+{
+ int ret = 0;
+
+ DPRINTF("save_snapshot_cleanup\n");
+
+ snap_state.total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) -
+ snap_state.total_time;
+
+ if (snap_state.file) {
+ ret = qemu_fclose(snap_state.file);
+ snap_state.file = NULL;
+ }
+
+ if (snap_state.target) {
+ if (!savevm_aborted()) {
+ /* try to truncate, but ignore errors (will fail on block devices).
+ * note1: bdrv_read() need whole blocks, so we need to round up
+ * note2: PVE requires 1024 (BDRV_SECTOR_SIZE*2) alignment
+ */
+ size_t size = QEMU_ALIGN_UP(snap_state.bs_pos, BDRV_SECTOR_SIZE*2);
+ blk_truncate(snap_state.target, size, false, PREALLOC_MODE_OFF, 0, NULL);
+ }
+ blk_op_unblock_all(snap_state.target, snap_state.blocker);
+ error_free(snap_state.blocker);
+ snap_state.blocker = NULL;
+ blk_unref(snap_state.target);
+ snap_state.target = NULL;
+
+ qemu_co_sleep_wake(&snap_state.target_close_wait);
+ }
+
+ return ret;
+}
+
+static void G_GNUC_PRINTF(1, 2) save_snapshot_error(const char *fmt, ...)
+{
+ va_list ap;
+ char *msg;
+
+ va_start(ap, fmt);
+ msg = g_strdup_vprintf(fmt, ap);
+ va_end(ap);
+
+ DPRINTF("save_snapshot_error: %s\n", msg);
+
+ if (!snap_state.error) {
+ error_set(&snap_state.error, ERROR_CLASS_GENERIC_ERROR, "%s", msg);
+ }
+
+ g_free (msg);
+
+ snap_state.state = SAVE_STATE_ERROR;
+}
+
+static void process_savevm_finalize(void *opaque)
+{
+ int ret;
+ AioContext *iohandler_ctx = iohandler_get_aio_context();
+ MigrationState *ms = migrate_get_current();
+
+ bool aborted = savevm_aborted();
+
+#ifdef DEBUG_SAVEVM_STATE
+ int64_t start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+#endif
+
+ qemu_bh_delete(snap_state.finalize_bh);
+ snap_state.finalize_bh = NULL;
+ snap_state.co = NULL;
+
+ /* We need to own the target bdrv's context for the following functions,
+ * so move it back. It can stay in the main context and live out its live
+ * there, since we're done with it after this method ends anyway.
+ */
+ aio_context_acquire(iohandler_ctx);
+ blk_set_aio_context(snap_state.target, qemu_get_aio_context(), NULL);
+ aio_context_release(iohandler_ctx);
+
+ ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
+ if (ret < 0) {
+ save_snapshot_error("vm_stop_force_state error %d", ret);
+ }
+
+ if (!aborted) {
+ /* skip state saving if we aborted, snapshot will be invalid anyway */
+ (void)qemu_savevm_state_complete_precopy(snap_state.file, false, false);
+ ret = qemu_file_get_error(snap_state.file);
+ if (ret < 0) {
+ save_snapshot_error("qemu_savevm_state_complete_precopy error %d", ret);
+ }
+ }
+
+ DPRINTF("state saving complete\n");
+ DPRINTF("timing: process_savevm_finalize (state saving) took %ld ms\n",
+ qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - start_time);
+
+ /* clear migration state */
+ migrate_set_state(&ms->state, MIGRATION_STATUS_SETUP,
+ ret || aborted ? MIGRATION_STATUS_FAILED : MIGRATION_STATUS_COMPLETED);
+ ms->to_dst_file = NULL;
+
+ qemu_savevm_state_cleanup();
+
+ ret = save_snapshot_cleanup();
+ if (ret < 0) {
+ save_snapshot_error("save_snapshot_cleanup error %d", ret);
+ } else if (snap_state.state == SAVE_STATE_ACTIVE) {
+ snap_state.state = SAVE_STATE_COMPLETED;
+ } else if (aborted) {
+ /*
+ * If there was an error, there's no need to set a new one here.
+ * If the snapshot was canceled, leave setting the state to
+ * qmp_savevm_end(), which is waked by save_snapshot_cleanup().
+ */
+ } else {
+ save_snapshot_error("process_savevm_cleanup: invalid state: %d",
+ snap_state.state);
+ }
+ if (snap_state.saved_vm_running) {
+ vm_start();
+ snap_state.saved_vm_running = false;
+ }
+
+ DPRINTF("timing: process_savevm_finalize (full) took %ld ms\n",
+ qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - start_time);
+}
+
+static void coroutine_fn process_savevm_co(void *opaque)
+{
+ int ret;
+ int64_t maxlen;
+ BdrvNextIterator it;
+ BlockDriverState *bs = NULL;
+
+#ifdef DEBUG_SAVEVM_STATE
+ int64_t start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+#endif
+
+ ret = qemu_file_get_error(snap_state.file);
+ if (ret < 0) {
+ save_snapshot_error("qemu_savevm_state_setup failed");
+ return;
+ }
+
+ while (snap_state.state == SAVE_STATE_ACTIVE) {
+ uint64_t pending_size, pend_precopy, pend_postcopy;
+ uint64_t threshold = 400 * 1000;
+
+ /*
+ * pending_{estimate,exact} are expected to be called without iothread
+ * lock. Similar to what is done in migration.c, call the exact variant
+ * only once pend_precopy in the estimate is below the threshold.
+ */
+ qemu_mutex_unlock_iothread();
+ qemu_savevm_state_pending_estimate(&pend_precopy, &pend_postcopy);
+ if (pend_precopy <= threshold) {
+ qemu_savevm_state_pending_exact(&pend_precopy, &pend_postcopy);
+ }
+ qemu_mutex_lock_iothread();
+ pending_size = pend_precopy + pend_postcopy;
+
+ /*
+ * A guest reaching this cutoff is dirtying lots of RAM. It should be
+ * large enough so that the guest can't dirty this much between the
+ * check and the guest actually being stopped, but it should be small
+ * enough to avoid long downtimes for non-hibernation snapshots.
+ */
+ maxlen = blk_getlength(snap_state.target) - 100*1024*1024;
+
+ /* Note that there is no progress for pend_postcopy when iterating */
+ if (pend_precopy > threshold && snap_state.bs_pos + pending_size < maxlen) {
+ ret = qemu_savevm_state_iterate(snap_state.file, false);
+ if (ret < 0) {
+ save_snapshot_error("qemu_savevm_state_iterate error %d", ret);
+ break;
+ }
+ DPRINTF("savevm iterate pending size %lu ret %d\n", pending_size, ret);
+ } else {
+ qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
+ global_state_store();
+
+ DPRINTF("savevm iterate complete\n");
+ break;
+ }
+ }
+
+ DPRINTF("timing: process_savevm_co took %ld ms\n",
+ qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - start_time);
+
+#ifdef DEBUG_SAVEVM_STATE
+ int64_t start_time_flush = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+#endif
+ /* If a drive runs in an IOThread we can flush it async, and only
+ * need to sync-flush whatever IO happens between now and
+ * vm_stop_force_state. bdrv_next can only be called from main AioContext,
+ * so move there now and after every flush.
+ */
+ aio_co_reschedule_self(qemu_get_aio_context());
+ for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
+ /* target has BDRV_O_NO_FLUSH, no sense calling bdrv_flush on it */
+ if (bs == blk_bs(snap_state.target)) {
+ continue;
+ }
+
+ AioContext *bs_ctx = bdrv_get_aio_context(bs);
+ if (bs_ctx != qemu_get_aio_context()) {
+ DPRINTF("savevm: async flushing drive %s\n", bs->filename);
+ aio_co_reschedule_self(bs_ctx);
+ bdrv_graph_co_rdlock();
+ bdrv_flush(bs);
+ bdrv_graph_co_rdunlock();
+ aio_co_reschedule_self(qemu_get_aio_context());
+ }
+ }
+
+ DPRINTF("timing: async flushing took %ld ms\n",
+ qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - start_time_flush);
+
+ qemu_bh_schedule(snap_state.finalize_bh);
+}
+
+void qmp_savevm_start(const char *statefile, Error **errp)
+{
+ Error *local_err = NULL;
+ MigrationState *ms = migrate_get_current();
+ AioContext *iohandler_ctx = iohandler_get_aio_context();
+
+ int bdrv_oflags = BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH;
+
+ if (snap_state.state != SAVE_STATE_DONE) {
+ error_set(errp, ERROR_CLASS_GENERIC_ERROR,
+ "VM snapshot already started\n");
+ return;
+ }
+
+ if (migration_is_running(ms->state)) {
+ error_set(errp, ERROR_CLASS_GENERIC_ERROR, QERR_MIGRATION_ACTIVE);
+ return;
+ }
+
+ if (migrate_block()) {
+ error_set(errp, ERROR_CLASS_GENERIC_ERROR,
+ "Block migration and snapshots are incompatible");
+ return;
+ }
+
+ /* initialize snapshot info */
+ snap_state.saved_vm_running = runstate_is_running();
+ snap_state.bs_pos = 0;
+ snap_state.total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+ snap_state.blocker = NULL;
+ snap_state.target_close_wait = (QemuCoSleep){ .to_wake = NULL };
+
+ if (snap_state.error) {
+ error_free(snap_state.error);
+ snap_state.error = NULL;
+ }
+
+ if (!statefile) {
+ vm_stop(RUN_STATE_SAVE_VM);
+ snap_state.state = SAVE_STATE_COMPLETED;
+ return;
+ }
+
+ if (qemu_savevm_state_blocked(errp)) {
+ return;
+ }
+
+ /* Open the image */
+ QDict *options = NULL;
+ options = qdict_new();
+ qdict_put_str(options, "driver", "raw");
+ snap_state.target = blk_new_open(statefile, NULL, options, bdrv_oflags, &local_err);
+ if (!snap_state.target) {
+ error_set(errp, ERROR_CLASS_GENERIC_ERROR, "failed to open '%s'", statefile);
+ goto restart;
+ }
+
+ QIOChannel *ioc = QIO_CHANNEL(qio_channel_savevm_async_new(snap_state.target,
+ &snap_state.bs_pos));
+ snap_state.file = qemu_file_new_output(ioc);
+
+ if (!snap_state.file) {
+ error_set(errp, ERROR_CLASS_GENERIC_ERROR, "failed to open '%s'", statefile);
+ goto restart;
+ }
+
+ /*
+ * qemu_savevm_* paths use migration code and expect a migration state.
+ * State is cleared in process_savevm_co, but has to be initialized
+ * here (blocking main thread, from QMP) to avoid race conditions.
+ */
+ migrate_init(ms);
+ memset(&mig_stats, 0, sizeof(mig_stats));
+ memset(&compression_counters, 0, sizeof(compression_counters));
+ ms->to_dst_file = snap_state.file;
+
+ error_setg(&snap_state.blocker, "block device is in use by savevm");
+ blk_op_block_all(snap_state.target, snap_state.blocker);
+
+ snap_state.state = SAVE_STATE_ACTIVE;
+ snap_state.finalize_bh = qemu_bh_new(process_savevm_finalize, &snap_state);
+ snap_state.co = qemu_coroutine_create(&process_savevm_co, NULL);
+ qemu_mutex_unlock_iothread();
+ qemu_savevm_state_header(snap_state.file);
+ qemu_savevm_state_setup(snap_state.file);
+ qemu_mutex_lock_iothread();
+
+ /* Async processing from here on out happens in iohandler context, so let
+ * the target bdrv have its home there.
+ */
+ blk_set_aio_context(snap_state.target, iohandler_ctx, &local_err);
+
+ aio_co_schedule(iohandler_ctx, snap_state.co);
+
+ return;
+
+restart:
+
+ save_snapshot_error("setup failed");
+
+ if (snap_state.saved_vm_running) {
+ vm_start();
+ snap_state.saved_vm_running = false;
+ }
+}
+
+void coroutine_fn qmp_savevm_end(Error **errp)
+{
+ int64_t timeout;
+
+ if (snap_state.state == SAVE_STATE_DONE) {
+ error_set(errp, ERROR_CLASS_GENERIC_ERROR,
+ "VM snapshot not started\n");
+ return;
+ }
+
+ if (snap_state.state == SAVE_STATE_ACTIVE) {
+ snap_state.state = SAVE_STATE_CANCELLED;
+ goto wait_for_close;
+ }
+
+ if (snap_state.saved_vm_running) {
+ vm_start();
+ snap_state.saved_vm_running = false;
+ }
+
+ snap_state.state = SAVE_STATE_DONE;
+
+wait_for_close:
+ if (!snap_state.target) {
+ DPRINTF("savevm-end: no target file open\n");
+ return;
+ }
+
+ /* wait until cleanup is done before returning, this ensures that after this
+ * call exits the statefile will be closed and can be removed immediately */
+ DPRINTF("savevm-end: waiting for cleanup\n");
+ timeout = 30L * 1000 * 1000 * 1000;
+ qemu_co_sleep_ns_wakeable(&snap_state.target_close_wait,
+ QEMU_CLOCK_REALTIME, timeout);
+ if (snap_state.target) {
+ save_snapshot_error("timeout waiting for target file close in "
+ "qmp_savevm_end");
+ /* we cannot assume the snapshot finished in this case, so leave the
+ * state alone - caller has to figure something out */
+ return;
+ }
+
+ // File closed and no other error, so ensure next snapshot can be started.
+ if (snap_state.state != SAVE_STATE_ERROR) {
+ snap_state.state = SAVE_STATE_DONE;
+ }
+
+ DPRINTF("savevm-end: cleanup done\n");
+}
+
+int load_snapshot_from_blockdev(const char *filename, Error **errp)
+{
+ BlockBackend *be;
+ Error *local_err = NULL;
+ Error *blocker = NULL;
+
+ QEMUFile *f;
+ size_t bs_pos = 0;
+ int ret = -EINVAL;
+
+ be = blk_new_open(filename, NULL, NULL, 0, &local_err);
+
+ if (!be) {
+ error_setg(errp, "Could not open VM state file");
+ goto the_end;
+ }
+
+ error_setg(&blocker, "block device is in use by load state");
+ blk_op_block_all(be, blocker);
+
+ /* restore the VM state */
+ f = qemu_file_new_input(QIO_CHANNEL(qio_channel_savevm_async_new(be, &bs_pos)));
+ if (!f) {
+ error_setg(errp, "Could not open VM state file");
+ goto the_end;
+ }
+
+ qemu_system_reset(SHUTDOWN_CAUSE_NONE);
+ ret = qemu_loadvm_state(f);
+
+ /* dirty bitmap migration has a special case we need to trigger manually */
+ dirty_bitmap_mig_before_vm_start();
+
+ qemu_fclose(f);
+
+ /* state_destroy assumes a real migration which would have added a yank */
+ yank_register_instance(MIGRATION_YANK_INSTANCE, &error_abort);
+
+ migration_incoming_state_destroy();
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Error while loading VM state");
+ goto the_end;
+ }
+
+ ret = 0;
+
+ the_end:
+ if (be) {
+ blk_op_unblock_all(be, blocker);
+ error_free(blocker);
+ blk_unref(be);
+ }
+ return ret;
+}
diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
index 6c559b48c8..91be698308 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -22,6 +22,7 @@
#include "monitor/monitor-internal.h"
#include "qapi/error.h"
#include "qapi/qapi-commands-control.h"
+#include "qapi/qapi-commands-migration.h"
#include "qapi/qapi-commands-misc.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qerror.h"
@@ -443,3 +444,40 @@ void hmp_info_mtree(Monitor *mon, const QDict *qdict)
mtree_info(flatview, dispatch_tree, owner, disabled);
}
+
+void hmp_savevm_start(Monitor *mon, const QDict *qdict)
+{
+ Error *errp = NULL;
+ const char *statefile = qdict_get_try_str(qdict, "statefile");
+
+ qmp_savevm_start(statefile, &errp);
+ hmp_handle_error(mon, errp);
+}
+
+void coroutine_fn hmp_savevm_end(Monitor *mon, const QDict *qdict)
+{
+ Error *errp = NULL;
+
+ qmp_savevm_end(&errp);
+ hmp_handle_error(mon, errp);
+}
+
+void hmp_info_savevm(Monitor *mon, const QDict *qdict)
+{
+ SaveVMInfo *info;
+ info = qmp_query_savevm(NULL);
+
+ if (info->status) {
+ monitor_printf(mon, "savevm status: %s\n", info->status);
+ monitor_printf(mon, "total time: %" PRIu64 " milliseconds\n",
+ info->total_time);
+ } else {
+ monitor_printf(mon, "savevm status: not running\n");
+ }
+ if (info->has_bytes) {
+ monitor_printf(mon, "Bytes saved: %"PRIu64"\n", info->bytes);
+ }
+ if (info->error) {
+ monitor_printf(mon, "Error: %s\n", info->error);
+ }
+}
diff --git a/qapi/migration.json b/qapi/migration.json
index 8843e74b59..aca0ca1ac1 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -291,6 +291,40 @@
'*dirty-limit-throttle-time-per-round': 'uint64',
'*dirty-limit-ring-full-time': 'uint64'} }
+##
+# @SaveVMInfo:
+#
+# Information about current migration process.
+#
+# @status: string describing the current savevm status.
+# This can be 'active', 'completed', 'failed'.
+# If this field is not returned, no savevm process
+# has been initiated
+#
+# @error: string containing error message is status is failed.
+#
+# @total-time: total amount of milliseconds since savevm started.
+# If savevm has ended, it returns the total save time
+#
+# @bytes: total amount of data transfered
+#
+# Since: 1.3
+##
+{ 'struct': 'SaveVMInfo',
+ 'data': {'*status': 'str', '*error': 'str',
+ '*total-time': 'int', '*bytes': 'int'} }
+
+##
+# @query-savevm:
+#
+# Returns information about current savevm process.
+#
+# Returns: @SaveVMInfo
+#
+# Since: 1.3
+##
+{ 'command': 'query-savevm', 'returns': 'SaveVMInfo' }
+
##
# @query-migrate:
#
diff --git a/qapi/misc.json b/qapi/misc.json
index cda2effa81..94a58bb0bf 100644
--- a/qapi/misc.json
+++ b/qapi/misc.json
@@ -456,6 +456,22 @@
##
{ 'command': 'query-fdsets', 'returns': ['FdsetInfo'] }
+##
+# @savevm-start:
+#
+# Prepare for snapshot and halt VM. Save VM state to statefile.
+#
+##
+{ 'command': 'savevm-start', 'data': { '*statefile': 'str' } }
+
+##
+# @savevm-end:
+#
+# Resume VM after a snapshot.
+#
+##
+{ 'command': 'savevm-end', 'coroutine': true }
+
##
# @CommandLineParameterType:
#
diff --git a/qemu-options.hx b/qemu-options.hx
index 8073f5edf5..dc1ececc9c 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -4483,6 +4483,18 @@ SRST
Start right away with a saved state (``loadvm`` in monitor)
ERST
+DEF("loadstate", HAS_ARG, QEMU_OPTION_loadstate, \
+ "-loadstate file\n" \
+ " start right away with a saved state\n",
+ QEMU_ARCH_ALL)
+SRST
+``-loadstate file``
+ Start right away with a saved state. This option does not rollback
+ disk state like @code{loadvm}, so user must make sure that disk
+ have correct state. @var{file} can be any valid device URL. See the section
+ for "Device URL Syntax" for more information.
+ERST
+
#ifndef _WIN32
DEF("daemonize", 0, QEMU_OPTION_daemonize, \
"-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL)
diff --git a/softmmu/vl.c b/softmmu/vl.c
index ba6ad8a8df..ddeace306e 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -164,6 +164,7 @@ static const char *accelerators;
static bool have_custom_ram_size;
static const char *ram_memdev_id;
static QDict *machine_opts_dict;
+static const char *loadstate;
static QTAILQ_HEAD(, ObjectOption) object_opts = QTAILQ_HEAD_INITIALIZER(object_opts);
static QTAILQ_HEAD(, DeviceOption) device_opts = QTAILQ_HEAD_INITIALIZER(device_opts);
static int display_remote;
@@ -2647,6 +2648,12 @@ void qmp_x_exit_preconfig(Error **errp)
if (loadvm) {
load_snapshot(loadvm, NULL, false, NULL, &error_fatal);
+ } else if (loadstate) {
+ Error *local_err = NULL;
+ if (load_snapshot_from_blockdev(loadstate, &local_err) < 0) {
+ error_report_err(local_err);
+ autostart = 0;
+ }
}
if (replay_mode != REPLAY_MODE_NONE) {
replay_vmstate_init();
@@ -3196,6 +3203,9 @@ void qemu_init(int argc, char **argv)
case QEMU_OPTION_loadvm:
loadvm = optarg;
break;
+ case QEMU_OPTION_loadstate:
+ loadstate = optarg;
+ break;
case QEMU_OPTION_full_screen:
dpy.has_full_screen = true;
dpy.full_screen = true;
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