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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 3/3] vfio/migration: Don't emit STOP_COPY state change event twice
Date: Tue, 30 Apr 2024 08:16:21 +0300	[thread overview]
Message-ID: <20240430051621.19597-4-avihaih@nvidia.com> (raw)
In-Reply-To: <20240430051621.19597-1-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 migration state change QAPI
event, the STOP_COPY state change event is undesirably emitted twice.

Prevent this by conditionally transitioning to STOP_COPY state in
vfio_save_complete_precopy().

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 | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 6bbccf6545..30a2b2ea74 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -591,14 +591,17 @@ static int vfio_save_iterate(QEMUFile *f, void *opaque)
 static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
 {
     VFIODevice *vbasedev = opaque;
+    VFIOMigration *migration = vbasedev->migration;
     ssize_t data_size;
     int ret;
 
     /* We reach here with device state STOP or STOP_COPY only */
-    ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP_COPY,
-                                   VFIO_DEVICE_STATE_STOP);
-    if (ret) {
-        return ret;
+    if (migration->device_state == VFIO_DEVICE_STATE_STOP) {
+        ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP_COPY,
+                                       VFIO_DEVICE_STATE_STOP);
+        if (ret) {
+            return ret;
+        }
     }
 
     do {
-- 
2.26.3



  parent reply	other threads:[~2024-04-30  5:17 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-30  5:16 [PATCH 0/3] qapi/vfio: Add VFIO device migration state change QAPI event Avihai Horon
2024-04-30  5:16 ` [PATCH 1/3] " Avihai Horon
2024-05-01 11:50   ` Joao Martins
2024-05-01 12:08     ` Avihai Horon
2024-05-06  4:52       ` Markus Armbruster
2024-05-06 10:07         ` Avihai Horon
2024-05-06 10:36           ` Markus Armbruster
2024-05-06 10:57             ` Avihai Horon
2024-05-02 11:19   ` Markus Armbruster
2024-05-05  7:48     ` Avihai Horon
2024-05-06  4:35       ` Markus Armbruster
2024-05-06  9:59         ` Avihai Horon
2024-04-30  5:16 ` [PATCH 2/3] vfio/migration: Emit " Avihai Horon
2024-05-01 11:50   ` Joao Martins
2024-05-01 12:28     ` Avihai Horon
2024-05-02 10:22       ` Joao Martins
2024-05-05  7:28         ` Avihai Horon
2024-05-06  4:56           ` Markus Armbruster
2024-05-06 14:38             ` Fabiano Rosas
2024-05-06 15:07               ` Peter Xu
2024-05-07  7:47                 ` Avihai Horon
2024-05-07 15:51                   ` Peter Xu
2024-05-07 16:21                     ` Avihai Horon
2024-04-30  5:16 ` Avihai Horon [this message]
2024-05-06 14:39   ` [PATCH 3/3] vfio/migration: Don't emit STOP_COPY state change event twice Cédric Le Goater
2024-05-06 15:01     ` Avihai Horon

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