From: Avihai Horon <avihaih@nvidia.com>
To: <qemu-devel@nongnu.org>
Cc: "Alex Williamson" <alex.williamson@redhat.com>,
"Cédric Le Goater" <clg@redhat.com>,
"Markus Armbruster" <armbru@redhat.com>,
"Michael Roth" <michael.roth@amd.com>,
"Eric Blake" <eblake@redhat.com>, "Peter Xu" <peterx@redhat.com>,
"Fabiano Rosas" <farosas@suse.de>,
"Joao Martins" <joao.m.martins@oracle.com>,
"Maor Gottlieb" <maorg@nvidia.com>,
"Avihai Horon" <avihaih@nvidia.com>
Subject: [PATCH v2 3/3] vfio/migration: Don't emit STOP_COPY VFIO migration QAPI event twice
Date: Thu, 9 May 2024 12:09:54 +0300 [thread overview]
Message-ID: <20240509090954.16447-4-avihaih@nvidia.com> (raw)
In-Reply-To: <20240509090954.16447-1-avihaih@nvidia.com>
When migrating a VFIO device that supports pre-copy, it is transitioned
to STOP_COPY twice: once in vfio_vmstate_change() and second time in
vfio_save_complete_precopy().
The second transition is harmless, as it's a STOP_COPY->STOP_COPY no-op
transition. However, with the newly added VFIO migration QAPI event, the
STOP_COPY event is undesirably emitted twice.
Prevent this by returning early in vfio_migration_set_state() if
new_state is the same as current device state.
Note that the STOP_COPY transition in vfio_save_complete_precopy() is
essential for VFIO devices that don't support pre-copy, for migrating an
already stopped guest and for snapshots.
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
---
hw/vfio/migration.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 5a359c4c78..14ef9c924e 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -143,6 +143,10 @@ static int vfio_migration_set_state(VFIODevice *vbasedev,
(struct vfio_device_feature_mig_state *)feature->data;
int ret;
+ if (new_state == migration->device_state) {
+ return 0;
+ }
+
feature->argsz = sizeof(buf);
feature->flags =
VFIO_DEVICE_FEATURE_SET | VFIO_DEVICE_FEATURE_MIG_DEVICE_STATE;
--
2.26.3
next prev parent reply other threads:[~2024-05-09 9:11 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-09 9:09 [PATCH v2 0/3] qapi/vfio: Add VFIO migration QAPI event Avihai Horon
2024-05-09 9:09 ` [PATCH v2 1/3] " Avihai Horon
2024-05-13 14:15 ` Cédric Le Goater
2024-05-09 9:09 ` [PATCH v2 2/3] vfio/migration: Emit " Avihai Horon
2024-05-13 14:01 ` Cédric Le Goater
2024-05-13 14:34 ` Avihai Horon
2024-05-13 14:43 ` Cédric Le Goater
2024-05-13 14:48 ` Avihai Horon
2024-05-09 9:09 ` Avihai Horon [this message]
2024-05-13 14:13 ` [PATCH v2 3/3] vfio/migration: Don't emit STOP_COPY VFIO migration QAPI event twice Cédric Le Goater
2024-05-13 14:38 ` Avihai Horon
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