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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Dietmar Maurer <dietmar@proxmox.com>
Date: Tue, 10 Mar 2020 13:49:27 +0100
Subject: [PATCH 17/32] PVE: internal snapshot async
Truncate at 1024 boundary (Fabian Ebner will send a patch for stable)
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
Signed-off-by: Dietmar Maurer <dietmar@proxmox.com>
---
Makefile.objs | 1 +
hmp-commands-info.hx | 13 +
hmp-commands.hx | 32 +++
include/migration/snapshot.h | 1 +
include/monitor/hmp.h | 5 +
monitor/hmp-cmds.c | 57 +++++
qapi/migration.json | 34 +++
qapi/misc.json | 32 +++
qemu-options.hx | 13 +
savevm-async.c | 464 +++++++++++++++++++++++++++++++++++
vl.c | 10 +
11 files changed, 662 insertions(+)
create mode 100644 savevm-async.c
diff --git a/Makefile.objs b/Makefile.objs
index 11ba1a36bd..f97b40f232 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -48,6 +48,7 @@ common-obj-y += bootdevice.o iothread.o
common-obj-y += dump/
common-obj-y += job-qmp.o
common-obj-y += monitor/
+common-obj-y += savevm-async.o
common-obj-y += net/
common-obj-y += qdev-monitor.o device-hotplug.o
common-obj-$(CONFIG_WIN32) += os-win32.o
diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
index 257ee7d7a3..139e673bea 100644
--- a/hmp-commands-info.hx
+++ b/hmp-commands-info.hx
@@ -608,6 +608,19 @@ STEXI
@item info migrate_cache_size
@findex info migrate_cache_size
Show current migration xbzrle cache size.
+ETEXI
+
+ {
+ .name = "savevm",
+ .args_type = "",
+ .params = "",
+ .help = "show savevm status",
+ .cmd = hmp_info_savevm,
+ },
+
+STEXI
+@item info savevm
+show savevm status
ETEXI
{
diff --git a/hmp-commands.hx b/hmp-commands.hx
index cfcc044ce4..104288322d 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1945,3 +1945,35 @@ ETEXI
STEXI
@end table
ETEXI
+
+ {
+ .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 = "snapshot-drive",
+ .args_type = "device:s,name:s",
+ .params = "device name",
+ .help = "Create internal snapshot.",
+ .cmd = hmp_snapshot_drive,
+ },
+
+ {
+ .name = "delete-drive-snapshot",
+ .args_type = "device:s,name:s",
+ .params = "device name",
+ .help = "Delete internal snapshot.",
+ .cmd = hmp_delete_drive_snapshot,
+ },
+
+ {
+ .name = "savevm-end",
+ .args_type = "",
+ .params = "",
+ .help = "Resume VM after snaphot.",
+ .cmd = hmp_savevm_end,
+ },
diff --git a/include/migration/snapshot.h b/include/migration/snapshot.h
index c85b6ec75b..4411b7121d 100644
--- a/include/migration/snapshot.h
+++ b/include/migration/snapshot.h
@@ -17,5 +17,6 @@
int save_snapshot(const char *name, Error **errp);
int load_snapshot(const char *name, 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 a0e9511440..c6ee8295f0 100644
--- a/include/monitor/hmp.h
+++ b/include/monitor/hmp.h
@@ -25,6 +25,7 @@ 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);
@@ -102,6 +103,10 @@ void hmp_netdev_add(Monitor *mon, const QDict *qdict);
void hmp_netdev_del(Monitor *mon, const QDict *qdict);
void hmp_getfd(Monitor *mon, const QDict *qdict);
void hmp_closefd(Monitor *mon, const QDict *qdict);
+void hmp_savevm_start(Monitor *mon, const QDict *qdict);
+void hmp_snapshot_drive(Monitor *mon, const QDict *qdict);
+void hmp_delete_drive_snapshot(Monitor *mon, const QDict *qdict);
+void hmp_savevm_end(Monitor *mon, const QDict *qdict);
void hmp_sendkey(Monitor *mon, const QDict *qdict);
void hmp_screendump(Monitor *mon, const QDict *qdict);
void hmp_nbd_server_start(Monitor *mon, const QDict *qdict);
diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
index 2e725ed818..90aa34be25 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -2607,6 +2607,63 @@ void hmp_info_memory_devices(Monitor *mon, const QDict *qdict)
hmp_handle_error(mon, &err);
}
+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 != NULL, statefile, &errp);
+ hmp_handle_error(mon, &errp);
+}
+
+void hmp_snapshot_drive(Monitor *mon, const QDict *qdict)
+{
+ Error *errp = NULL;
+ const char *name = qdict_get_str(qdict, "name");
+ const char *device = qdict_get_str(qdict, "device");
+
+ qmp_snapshot_drive(device, name, &errp);
+ hmp_handle_error(mon, &errp);
+}
+
+void hmp_delete_drive_snapshot(Monitor *mon, const QDict *qdict)
+{
+ Error *errp = NULL;
+ const char *name = qdict_get_str(qdict, "name");
+ const char *device = qdict_get_str(qdict, "device");
+
+ qmp_delete_drive_snapshot(device, name, &errp);
+ hmp_handle_error(mon, &errp);
+}
+
+void 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->has_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->has_error) {
+ monitor_printf(mon, "Error: %s\n", info->error);
+ }
+}
+
void hmp_info_iothreads(Monitor *mon, const QDict *qdict)
{
IOThreadInfoList *info_list = qmp_query_iothreads(NULL);
diff --git a/qapi/migration.json b/qapi/migration.json
index b7348d0c8b..2792409977 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -222,6 +222,40 @@
'*compression': 'CompressionStats',
'*socket-address': ['SocketAddress'] } }
+##
+# @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 ed65ed27e3..4c4618a574 100644
--- a/qapi/misc.json
+++ b/qapi/misc.json
@@ -1368,6 +1368,38 @@
##
{ 'command': 'query-fdsets', 'returns': ['FdsetInfo'] }
+##
+# @savevm-start:
+#
+# Prepare for snapshot and halt VM. Save VM state to statefile.
+#
+##
+{ 'command': 'savevm-start', 'data': { '*statefile': 'str' } }
+
+##
+# @snapshot-drive:
+#
+# Create an internal drive snapshot.
+#
+##
+{ 'command': 'snapshot-drive', 'data': { 'device': 'str', 'name': 'str' } }
+
+##
+# @delete-drive-snapshot:
+#
+# Delete a drive snapshot.
+#
+##
+{ 'command': 'delete-drive-snapshot', 'data': { 'device': 'str', 'name': 'str' } }
+
+##
+# @savevm-end:
+#
+# Resume VM after a snapshot.
+#
+##
+{ 'command': 'savevm-end' }
+
##
# @AcpiTableOptions:
#
diff --git a/qemu-options.hx b/qemu-options.hx
index 65c9473b73..4cb2681bfc 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3818,6 +3818,19 @@ STEXI
Start right away with a saved state (@code{loadvm} in monitor)
ETEXI
+DEF("loadstate", HAS_ARG, QEMU_OPTION_loadstate, \
+ "-loadstate file\n" \
+ " start right away with a saved state\n",
+ QEMU_ARCH_ALL)
+STEXI
+@item -loadstate @var{file}
+@findex -loadstate
+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.
+ETEXI
+
#ifndef _WIN32
DEF("daemonize", 0, QEMU_OPTION_daemonize, \
"-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL)
diff --git a/savevm-async.c b/savevm-async.c
new file mode 100644
index 0000000000..54ceeae26c
--- /dev/null
+++ b/savevm-async.c
@@ -0,0 +1,464 @@
+#include "qemu/osdep.h"
+#include "migration/migration.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/main-loop.h"
+#include "qemu/rcu.h"
+
+/* #define DEBUG_SAVEVM_STATE */
+
+/* used while emulated sync operation in progress */
+#define NOT_DONE -EINPROGRESS
+
+#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 *cleanup_bh;
+ QemuThread thread;
+} snap_state;
+
+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->has_status = true;
+ info->status = g_strdup("failed");
+ info->has_total_time = true;
+ info->total_time = s->total_time;
+ if (s->error) {
+ info->has_error = true;
+ info->error = g_strdup(error_get_pretty(s->error));
+ }
+ break;
+ case SAVE_STATE_ACTIVE:
+ info->has_status = true;
+ 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->has_status = true;
+ 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);
+ }
+
+ if (snap_state.target) {
+ /* 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, 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;
+ }
+
+ return ret;
+}
+
+static void 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 int block_state_close(void *opaque, Error **errp)
+{
+ snap_state.file = NULL;
+ return blk_flush(snap_state.target);
+}
+
+typedef struct BlkRwCo {
+ int64_t offset;
+ QEMUIOVector *qiov;
+ ssize_t ret;
+} BlkRwCo;
+
+static void coroutine_fn block_state_write_entry(void *opaque) {
+ BlkRwCo *rwco = opaque;
+ rwco->ret = blk_co_pwritev(snap_state.target, rwco->offset, rwco->qiov->size,
+ rwco->qiov, 0);
+}
+
+static ssize_t block_state_writev_buffer(void *opaque, struct iovec *iov,
+ int iovcnt, int64_t pos, Error **errp)
+{
+ QEMUIOVector qiov;
+ BlkRwCo rwco;
+
+ assert(pos == snap_state.bs_pos);
+ rwco = (BlkRwCo) {
+ .offset = pos,
+ .qiov = &qiov,
+ .ret = NOT_DONE,
+ };
+
+ qemu_iovec_init_external(&qiov, iov, iovcnt);
+
+ if (qemu_in_coroutine()) {
+ block_state_write_entry(&rwco);
+ } else {
+ Coroutine *co = qemu_coroutine_create(&block_state_write_entry, &rwco);
+ bdrv_coroutine_enter(blk_bs(snap_state.target), co);
+ BDRV_POLL_WHILE(blk_bs(snap_state.target), rwco.ret == NOT_DONE);
+ }
+ if (rwco.ret < 0) {
+ return rwco.ret;
+ }
+
+ snap_state.bs_pos += qiov.size;
+ return qiov.size;
+}
+
+static const QEMUFileOps block_file_ops = {
+ .writev_buffer = block_state_writev_buffer,
+ .close = block_state_close,
+};
+
+static void process_savevm_cleanup(void *opaque)
+{
+ int ret;
+ qemu_bh_delete(snap_state.cleanup_bh);
+ snap_state.cleanup_bh = NULL;
+ qemu_mutex_unlock_iothread();
+ qemu_thread_join(&snap_state.thread);
+ qemu_mutex_lock_iothread();
+ 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 {
+ 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;
+ }
+}
+
+static void *process_savevm_thread(void *opaque)
+{
+ int ret;
+ int64_t maxlen;
+
+ rcu_register_thread();
+
+ qemu_savevm_state_header(snap_state.file);
+ qemu_savevm_state_setup(snap_state.file);
+ ret = qemu_file_get_error(snap_state.file);
+
+ if (ret < 0) {
+ save_snapshot_error("qemu_savevm_state_setup failed");
+ rcu_unregister_thread();
+ return NULL;
+ }
+
+ while (snap_state.state == SAVE_STATE_ACTIVE) {
+ uint64_t pending_size, pend_precopy, pend_compatible, pend_postcopy;
+
+ qemu_savevm_state_pending(snap_state.file, 0, &pend_precopy, &pend_compatible, &pend_postcopy);
+ pending_size = pend_precopy + pend_compatible + pend_postcopy;
+
+ maxlen = blk_getlength(snap_state.target) - 30*1024*1024;
+
+ if (pending_size > 400000 && snap_state.bs_pos + pending_size < maxlen) {
+ qemu_mutex_lock_iothread();
+ ret = qemu_savevm_state_iterate(snap_state.file, false);
+ if (ret < 0) {
+ save_snapshot_error("qemu_savevm_state_iterate error %d", ret);
+ break;
+ }
+ qemu_mutex_unlock_iothread();
+ DPRINTF("savevm inerate pending size %lu ret %d\n", pending_size, ret);
+ } else {
+ qemu_mutex_lock_iothread();
+ qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
+ ret = global_state_store();
+ if (ret) {
+ save_snapshot_error("global_state_store error %d", ret);
+ break;
+ }
+ ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
+ if (ret < 0) {
+ save_snapshot_error("vm_stop_force_state error %d", ret);
+ break;
+ }
+ DPRINTF("savevm inerate finished\n");
+ /* upstream made the return value here inconsistent
+ * (-1 instead of 'ret' in one case and 0 after flush which can
+ * still set a file error...)
+ */
+ (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_iterate error %d", ret);
+ break;
+ }
+ qemu_savevm_state_cleanup();
+ DPRINTF("save complete\n");
+ break;
+ }
+ }
+
+ qemu_bh_schedule(snap_state.cleanup_bh);
+ qemu_mutex_unlock_iothread();
+
+ rcu_unregister_thread();
+ return NULL;
+}
+
+void qmp_savevm_start(bool has_statefile, const char *statefile, Error **errp)
+{
+ Error *local_err = NULL;
+
+ 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;
+ }
+
+ /* 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;
+
+ if (snap_state.error) {
+ error_free(snap_state.error);
+ snap_state.error = NULL;
+ }
+
+ if (!has_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;
+ }
+
+ snap_state.file = qemu_fopen_ops(&snap_state, &block_file_ops);
+
+ if (!snap_state.file) {
+ error_set(errp, ERROR_CLASS_GENERIC_ERROR, "failed to open '%s'", statefile);
+ goto restart;
+ }
+
+
+ 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.cleanup_bh = qemu_bh_new(process_savevm_cleanup, &snap_state);
+ qemu_thread_create(&snap_state.thread, "savevm-async", process_savevm_thread,
+ NULL, QEMU_THREAD_JOINABLE);
+
+ return;
+
+restart:
+
+ save_snapshot_error("setup failed");
+
+ if (snap_state.saved_vm_running) {
+ vm_start();
+ }
+}
+
+void qmp_savevm_end(Error **errp)
+{
+ 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;
+ return;
+ }
+
+ if (snap_state.saved_vm_running) {
+ vm_start();
+ }
+
+ snap_state.state = SAVE_STATE_DONE;
+}
+
+// FIXME: Deprecated
+void qmp_snapshot_drive(const char *device, const char *name, Error **errp)
+{
+ // Compatibility to older qemu-server.
+ qmp_blockdev_snapshot_internal_sync(device, name, errp);
+}
+
+// FIXME: Deprecated
+void qmp_delete_drive_snapshot(const char *device, const char *name,
+ Error **errp)
+{
+ // Compatibility to older qemu-server.
+ (void)qmp_blockdev_snapshot_delete_internal_sync(device, false, NULL,
+ true, name, errp);
+}
+
+static ssize_t loadstate_get_buffer(void *opaque, uint8_t *buf, int64_t pos,
+ size_t size, Error **errp)
+{
+ BlockBackend *be = opaque;
+ int64_t maxlen = blk_getlength(be);
+ if (pos > maxlen) {
+ return -EIO;
+ }
+ if ((pos + size) > maxlen) {
+ size = maxlen - pos - 1;
+ }
+ if (size == 0) {
+ return 0;
+ }
+ return blk_pread(be, pos, buf, size);
+}
+
+static const QEMUFileOps loadstate_file_ops = {
+ .get_buffer = loadstate_get_buffer,
+};
+
+int load_snapshot_from_blockdev(const char *filename, Error **errp)
+{
+ BlockBackend *be;
+ Error *local_err = NULL;
+ Error *blocker = NULL;
+
+ QEMUFile *f;
+ 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_fopen_ops(be, &loadstate_file_ops);
+ 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);
+
+ qemu_fclose(f);
+ 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/vl.c b/vl.c
index 6a65a64bfd..1616f55a38 100644
--- a/vl.c
+++ b/vl.c
@@ -2840,6 +2840,7 @@ int main(int argc, char **argv, char **envp)
int optind;
const char *optarg;
const char *loadvm = NULL;
+ const char *loadstate = NULL;
MachineClass *machine_class;
const char *cpu_option;
const char *vga_model = NULL;
@@ -3430,6 +3431,9 @@ int main(int argc, char **argv, char **envp)
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;
@@ -4442,6 +4446,12 @@ int main(int argc, char **argv, char **envp)
autostart = 0;
exit(1);
}
+ } 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();
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