On 11/05/21 10:56, Dr. David Alan Gilbert wrote:
> * Paolo Bonzini (pbonzini@redhat.com) wrote:
>> The HMP loadvm code is calling load_snapshot rather than
>> qmp_snapshot_load, in order to bypass the job infrastructure. The code
>> around it is almost the same, with one difference: hmp_loadvm is
>> restarting the VM if load_snapshot fails, qmp_snapshot_load is doing so
>> if load_snapshot succeeds.
>>
>> Fix the bug in QMP by moving the common code to load_snapshot.
>
> See my comment:
> https://lists.gnu.org/archive/html/qemu-devel/2021-05/msg01103.html
>
> but you've also lost Eric's Rb.
Sorry, I missed both replies. As Daniel pointed out, the bug is in the
QMP version. Kevin has the correct fix, I'll send the cleanup of
vm_stop/vm_start separately on top of his patch.
Paolo
> Dave
>
>> Cc: qemu-stable@nongnu.org
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> ---
>> migration/savevm.c | 16 ++++++++--------
>> monitor/hmp-cmds.c | 7 +------
>> 2 files changed, 9 insertions(+), 14 deletions(-)
>>
>> diff --git a/migration/savevm.c b/migration/savevm.c
>> index 52e2d72e4b..a899191cbf 100644
>> --- a/migration/savevm.c
>> +++ b/migration/savevm.c
>> @@ -2992,6 +2992,7 @@ bool load_snapshot(const char *name, const char *vmstate,
>> int ret;
>> AioContext *aio_context;
>> MigrationIncomingState *mis = migration_incoming_get_current();
>> + int saved_vm_running = runstate_is_running();
>>
>> if (!bdrv_all_can_snapshot(has_devices, devices, errp)) {
>> return false;
>> @@ -3024,6 +3025,8 @@ bool load_snapshot(const char *name, const char *vmstate,
>> return false;
>> }
>>
>> + vm_stop(RUN_STATE_RESTORE_VM);
>> +
>> /*
>> * Flush the record/replay queue. Now the VM state is going
>> * to change. Therefore we don't need to preserve its consistency
>> @@ -3061,13 +3064,17 @@ bool load_snapshot(const char *name, const char *vmstate,
>>
>> if (ret < 0) {
>> error_setg(errp, "Error %d while loading VM state", ret);
>> - return false;
>> + goto err_restart;
>> }
>>
>> return true;
>>
>> err_drain:
>> bdrv_drain_all_end();
>> +err_restart:
>> + if (saved_vm_running) {
>> + vm_start();
>> + }
>> return false;
>> }
>>
>> @@ -3135,17 +3142,10 @@ static void snapshot_load_job_bh(void *opaque)
>> {
>> Job *job = opaque;
>> SnapshotJob *s = container_of(job, SnapshotJob, common);
>> - int orig_vm_running;
>>
>> job_progress_set_remaining(&s->common, 1);
>>
>> - orig_vm_running = runstate_is_running();
>> - vm_stop(RUN_STATE_RESTORE_VM);
>> -
>> s->ret = load_snapshot(s->tag, s->vmstate, true, s->devices, s->errp);
>> - if (s->ret && orig_vm_running) {
>> - vm_start();
>> - }
>>
>> job_progress_update(&s->common, 1);
>>
>> diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
>> index 0ad5b77477..a39436c8cb 100644
>> --- a/monitor/hmp-cmds.c
>> +++ b/monitor/hmp-cmds.c
>> @@ -1127,15 +1127,10 @@ void hmp_balloon(Monitor *mon, const QDict *qdict)
>>
>> void hmp_loadvm(Monitor *mon, const QDict *qdict)
>> {
>> - int saved_vm_running = runstate_is_running();
>> const char *name = qdict_get_str(qdict, "name");
>> Error *err = NULL;
>>
>> - vm_stop(RUN_STATE_RESTORE_VM);
>> -
>> - if (!load_snapshot(name, NULL, false, NULL, &err) && saved_vm_running) {
>> - vm_start();
>> - }
>> + load_snapshot(name, NULL, false, NULL, &err);
>> hmp_handle_error(mon, err);
>> }
>>
>> --
>> 2.26.2
>>
>>
>>