On 04/05/2017 10:42, Pavel Dovgalyuk wrote:
> From: Pavel Dovgalyuk <pavel.dovga...@ispras.ru>
>
> This patch does not allows saving/loading vmstate when
> replay events queue is not empty. There is no reliable
> way to save events queue, because it describes internal
> coroutine state. Therefore saving and loading operations
> should be deferred to another record/replay step.
Can it actually be non-empty after bdrv_drain_all?
Paolo
> Signed-off-by: Pavel Dovgalyuk <pavel.dovga...@ispras.ru>
> ---
> include/sysemu/replay.h | 3 +++
> migration/savevm.c | 13 +++++++++++++
> replay/replay-snapshot.c | 6 ++++++
> 3 files changed, 22 insertions(+)
>
> diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h
> index f1c0712795..5c9db2a2ef 100644
> --- a/include/sysemu/replay.h
> +++ b/include/sysemu/replay.h
> @@ -164,5 +164,8 @@ void replay_audio_in(int *recorded, void *samples, int
> *wpos, int size);
> /*! Called at the start of execution.
> Loads or saves initial vmstate depending on execution mode. */
> void replay_vmstate_init(void);
> +/*! Called to ensure that replay state is consistent and VM snapshot
> + can be created */
> +bool replay_can_snapshot(void);
>
> #endif
> diff --git a/migration/savevm.c b/migration/savevm.c
> index 03ae1bdeb4..358d22170d 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -54,6 +54,7 @@
> #include "qemu/cutils.h"
> #include "io/channel-buffer.h"
> #include "io/channel-file.h"
> +#include "sysemu/replay.h"
>
> #ifndef ETH_P_RARP
> #define ETH_P_RARP 0x8035
> @@ -2083,6 +2084,12 @@ int save_vmstate(Monitor *mon, const char *name)
> Error *local_err = NULL;
> AioContext *aio_context;
>
> + if (!replay_can_snapshot()) {
> + monitor_printf(mon, "Record/replay does not allow making snapshot
> right now. "
> + "Try stopping at another step.\n");
> + return ret;
> + }
> +
> if (!bdrv_all_can_snapshot(&bs)) {
> monitor_printf(mon, "Device '%s' is writable but does not "
> "support snapshots.\n", bdrv_get_device_name(bs));
> @@ -2244,6 +2251,12 @@ int load_vmstate(const char *name)
> AioContext *aio_context;
> MigrationIncomingState *mis = migration_incoming_get_current();
>
> + if (!replay_can_snapshot()) {
> + error_report("Record/replay does not allow loading snapshot right
> now. "
> + "Try stopping at another step.\n");
> + return -EINVAL;
> + }
> +
> if (!bdrv_all_can_snapshot(&bs)) {
> error_report("Device '%s' is writable but does not support
> snapshots.",
> bdrv_get_device_name(bs));
> diff --git a/replay/replay-snapshot.c b/replay/replay-snapshot.c
> index 65e2d375c2..438d82ec33 100644
> --- a/replay/replay-snapshot.c
> +++ b/replay/replay-snapshot.c
> @@ -76,3 +76,9 @@ void replay_vmstate_init(void)
> }
> }
> }
> +
> +bool replay_can_snapshot(void)
> +{
> + return replay_mode == REPLAY_MODE_NONE
> + || !replay_has_events();
> +}
>
