From: Erik Fastermann <e.fastermann@proxmox.com>
To: pve-devel@lists.proxmox.com
Cc: Erik Fastermann <e.fastermann@proxmox.com>
Subject: [PATCH qemu v2 9/9] savevm-async: restore run state from before snapshot
Date: Mon, 7 Sep 2026 11:47:43 +0200 [thread overview]
Message-ID: <20260907094744.131193-10-e.fastermann@proxmox.com> (raw)
In-Reply-To: <20260907094744.131193-1-e.fastermann@proxmox.com>
A snapshot of a paused VM left it in finish-migrate, where it stayed
until the VM was restarted. vm_needs_start only recorded whether the VM
had been running, so there was nothing to restore a paused VM to.
Store the run state instead and put it back, similar to
migration_iteration_finish().
Signed-off-by: Erik Fastermann <e.fastermann@proxmox.com>
---
...async-for-background-state-snapshots.patch | 57 ++++++++++++-------
...add-optional-buffer-size-to-QEMUFile.patch | 6 +-
...se-migration-blocker-check-for-snaps.patch | 4 +-
3 files changed, 41 insertions(+), 26 deletions(-)
diff --git a/debian/patches/pve/0017-PVE-add-savevm-async-for-background-state-snapshots.patch b/debian/patches/pve/0017-PVE-add-savevm-async-for-background-state-snapshots.patch
index 94908d7..9a4a049 100644
--- a/debian/patches/pve/0017-PVE-add-savevm-async-for-background-state-snapshots.patch
+++ b/debian/patches/pve/0017-PVE-add-savevm-async-for-background-state-snapshots.patch
@@ -40,7 +40,8 @@ Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
[EF: drop QIOChannel reference
free migration vmdesc
release resources on start failure path
- include reason when file open fails]
+ include reason when file open fails
+ restore run state from before snapshot]
Signed-off-by: Erik Fastermann <e.fastermann@proxmox.com>
---
hmp-commands-info.hx | 13 +
@@ -48,13 +49,13 @@ Signed-off-by: Erik Fastermann <e.fastermann@proxmox.com>
include/migration/snapshot.h | 2 +
include/monitor/hmp.h | 3 +
migration/meson.build | 1 +
- migration/savevm-async.c | 634 +++++++++++++++++++++++++++++++++++
- monitor/hmp-cmds.c | 38 +++
+ migration/savevm-async.c | 648 +++++++++++++++++++++++++++++++++++
+ monitor/hmp-cmds.c | 38 ++
qapi/migration.json | 34 ++
qapi/misc.json | 25 ++
qemu-options.hx | 12 +
system/vl.c | 10 +
- 11 files changed, 789 insertions(+)
+ 11 files changed, 803 insertions(+)
create mode 100644 migration/savevm-async.c
diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
@@ -152,10 +153,10 @@ index 0222d5ea6e..90d62d5723 100644
), gnutls, zlib)
diff --git a/migration/savevm-async.c b/migration/savevm-async.c
new file mode 100644
-index 0000000000..56c60b345f
+index 0000000000..fe455016ab
--- /dev/null
+++ b/migration/savevm-async.c
-@@ -0,0 +1,634 @@
+@@ -0,0 +1,648 @@
+#include "qemu/osdep.h"
+#include "migration/channel-savevm-async.h"
+#include "migration/migration.h"
@@ -210,7 +211,7 @@ index 0000000000..56c60b345f
+ int state;
+ Error *error;
+ Error *blocker;
-+ bool vm_needs_start;
++ RunState vm_old_state;
+ bool skip_vm_start;
+ QEMUFile *file;
+ int64_t total_time;
@@ -230,6 +231,24 @@ index 0000000000..56c60b345f
+ return snap_state.state == SAVE_STATE_COMPLETED && snap_state.skip_vm_start;
+}
+
++static void restore_vm_old_state(void)
++{
++ RunState old_state = snap_state.vm_old_state;
++
++ if (old_state == RUN_STATE__MAX) {
++ return;
++ }
++ snap_state.vm_old_state = RUN_STATE__MAX;
++
++ if (runstate_is_live(old_state)) {
++ if (!should_skip_vm_start() && !runstate_check(RUN_STATE_SHUTDOWN)) {
++ vm_start();
++ }
++ } else if (runstate_check(RUN_STATE_FINISH_MIGRATE)) {
++ runstate_set(old_state);
++ }
++}
++
+SaveVMInfo *qmp_query_savevm(Error **errp)
+{
+ SaveVMInfo *info = g_malloc0(sizeof(*info));
@@ -352,7 +371,7 @@ index 0000000000..56c60b345f
+ */
+ blk_set_aio_context(snap_state.target, qemu_get_aio_context(), NULL);
+
-+ snap_state.vm_needs_start = runstate_is_running();
++ snap_state.vm_old_state = runstate_get();
+ ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
+ if (ret < 0) {
+ save_snapshot_error("vm_stop_force_state error %d", ret);
@@ -396,12 +415,7 @@ index 0000000000..56c60b345f
+ save_snapshot_error("process_savevm_cleanup: invalid state: %d",
+ snap_state.state);
+ }
-+ if (snap_state.vm_needs_start) {
-+ if (!should_skip_vm_start()) {
-+ vm_start();
-+ }
-+ snap_state.vm_needs_start = false;
-+ }
++ restore_vm_old_state();
+
+ DPRINTF("timing: process_savevm_finalize (full) took %ld ms\n",
+ qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - start_time);
@@ -529,12 +543,18 @@ index 0000000000..56c60b345f
+ return;
+ }
+
++ if (runstate_check(RUN_STATE_INMIGRATE)) {
++ error_setg(errp, "There's an incoming migration in progress");
++ return;
++ }
++
+ /* initialize snapshot info */
+ 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 };
+ snap_state.skip_vm_start = has_skip_vm_start && skip_vm_start;
++ snap_state.vm_old_state = RUN_STATE__MAX;
+
+ if (snap_state.error) {
+ error_free(snap_state.error);
@@ -542,7 +562,7 @@ index 0000000000..56c60b345f
+ }
+
+ if (!statefile) {
-+ snap_state.vm_needs_start = runstate_is_running();
++ snap_state.vm_old_state = runstate_get();
+ vm_stop(RUN_STATE_SAVE_VM);
+ snap_state.state = SAVE_STATE_COMPLETED;
+ return;
@@ -703,12 +723,7 @@ index 0000000000..56c60b345f
+ return;
+ }
+
-+ if (snap_state.vm_needs_start) {
-+ if (!should_skip_vm_start()) {
-+ vm_start();
-+ }
-+ snap_state.vm_needs_start = false;
-+ }
++ restore_vm_old_state();
+
+ qemu_coroutine_enter(wait_for_close);
+}
diff --git a/debian/patches/pve/0018-PVE-add-optional-buffer-size-to-QEMUFile.patch b/debian/patches/pve/0018-PVE-add-optional-buffer-size-to-QEMUFile.patch
index 4345f42..e29c721 100644
--- a/debian/patches/pve/0018-PVE-add-optional-buffer-size-to-QEMUFile.patch
+++ b/debian/patches/pve/0018-PVE-add-optional-buffer-size-to-QEMUFile.patch
@@ -186,10 +186,10 @@ index a390554208..eda093b16a 100644
G_DEFINE_AUTOPTR_CLEANUP_FUNC(QEMUFile, qemu_fclose)
diff --git a/migration/savevm-async.c b/migration/savevm-async.c
-index 56c60b345f..a460970dd5 100644
+index fe455016ab..91a3f404fb 100644
--- a/migration/savevm-async.c
+++ b/migration/savevm-async.c
-@@ -425,7 +425,7 @@ void qmp_savevm_start(const char *statefile, bool has_skip_vm_start,
+@@ -444,7 +444,7 @@ void qmp_savevm_start(const char *statefile, bool has_skip_vm_start,
QIOChannel *ioc = QIO_CHANNEL(qio_channel_savevm_async_new(snap_state.target,
&snap_state.bs_pos));
@@ -198,7 +198,7 @@ index 56c60b345f..a460970dd5 100644
object_unref(ioc);
if (!snap_state.file) {
-@@ -589,7 +589,7 @@ int load_snapshot_from_blockdev(const char *filename, Error **errp)
+@@ -603,7 +603,7 @@ int load_snapshot_from_blockdev(const char *filename, Error **errp)
/* restore the VM state */
QIOChannel *ioc = QIO_CHANNEL(qio_channel_savevm_async_new(be, &bs_pos));
diff --git a/debian/patches/pve/0046-savevm-async-reuse-migration-blocker-check-for-snaps.patch b/debian/patches/pve/0046-savevm-async-reuse-migration-blocker-check-for-snaps.patch
index d87875b..410f13b 100644
--- a/debian/patches/pve/0046-savevm-async-reuse-migration-blocker-check-for-snaps.patch
+++ b/debian/patches/pve/0046-savevm-async-reuse-migration-blocker-check-for-snaps.patch
@@ -136,10 +136,10 @@ index b6888daced..80eb0dcd1f 100644
bool migration_in_postcopy(void);
bool migration_postcopy_is_alive(MigrationStatus state);
diff --git a/migration/savevm-async.c b/migration/savevm-async.c
-index a460970dd5..b703c5d5a3 100644
+index 91a3f404fb..6c16000898 100644
--- a/migration/savevm-async.c
+++ b/migration/savevm-async.c
-@@ -390,7 +390,7 @@ void qmp_savevm_start(const char *statefile, bool has_skip_vm_start,
+@@ -409,7 +409,7 @@ void qmp_savevm_start(const char *statefile, bool has_skip_vm_start,
return;
}
--
2.47.3
next prev parent reply other threads:[~2026-09-07 9:49 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-07 9:47 [PATCH qemu v2 0/9] savevm-async: fix stuck paused vm after snapshot Erik Fastermann
2026-09-07 9:47 ` [PATCH qemu v2 1/9] d/patches: normalize header of pbs-restore no-cache patch Erik Fastermann
2026-09-07 9:47 ` [PATCH qemu v2 2/9] pbs-restore: keep callback data on the stack Erik Fastermann
2026-09-07 9:47 ` [PATCH qemu v2 3/9] migration/qemu-file: allocate buffer with g_malloc Erik Fastermann
2026-09-07 9:47 ` [PATCH qemu v2 4/9] migration/pbs-state: check allocation of incoming state buffer Erik Fastermann
2026-09-07 9:47 ` [PATCH qemu v2 5/9] savevm-async: drop QIOChannel reference Erik Fastermann
2026-09-08 14:22 ` Fiona Ebner
2026-09-07 9:47 ` [PATCH qemu v2 6/9] savevm-async: free migration vmdesc Erik Fastermann
2026-09-08 14:22 ` Fiona Ebner
2026-09-07 9:47 ` [PATCH qemu v2 7/9] savevm-async: release resources on start failure path Erik Fastermann
2026-09-07 9:47 ` [PATCH qemu v2 8/9] savevm-async: include reason when file open fails Erik Fastermann
2026-09-07 9:47 ` Erik Fastermann [this message]
2026-09-08 14:22 ` [PATCH qemu v2 9/9] savevm-async: restore run state from before snapshot Fiona Ebner
2026-09-08 14:21 ` partially-applied: [PATCH qemu v2 0/9] savevm-async: fix stuck paused vm after snapshot Fiona Ebner
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