From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57526) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d6E35-0001ZQ-DV for qemu-devel@nongnu.org; Thu, 04 May 2017 06:31:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d6E33-0006LM-2N for qemu-devel@nongnu.org; Thu, 04 May 2017 06:31:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:32880) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1d6E32-0006Jn-Pn for qemu-devel@nongnu.org; Thu, 04 May 2017 06:31:49 -0400 References: <20170504084135.7488.24715.stgit@PASHA-ISP> <20170504084210.7488.37561.stgit@PASHA-ISP> From: Paolo Bonzini Message-ID: Date: Thu, 4 May 2017 12:31:42 +0200 MIME-Version: 1.0 In-Reply-To: <20170504084210.7488.37561.stgit@PASHA-ISP> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v9 06/10] replay: fix save/load vm for non-empty queue List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Pavel Dovgalyuk , qemu-devel@nongnu.org Cc: kwolf@redhat.com, peter.maydell@linaro.org, mst@redhat.com, jasowang@redhat.com, quintela@redhat.com, kraxel@redhat.com On 04/05/2017 10:42, Pavel Dovgalyuk wrote: > From: Pavel Dovgalyuk > > 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 > --- > 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(); > +} >