qemu-kvm/SOURCES/kvm-vfio-migration-Skip-log_sync-during-migration-SETUP-.patch

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2023-11-07 09:43:59 +00:00
From 76208f7824d5139ac8d86140b0e01031b67638cc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= <clg@redhat.com>
Date: Wed, 12 Jul 2023 17:46:56 +0200
Subject: [PATCH 04/37] vfio/migration: Skip log_sync during migration SETUP
state
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RH-Author: Cédric Le Goater <clg@redhat.com>
RH-MergeRequest: 179: vfio: live migration support
RH-Bugzilla: 2192818
RH-Acked-by: Eric Auger <eric.auger@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Commit: [2/28] 4c340992b472ac4627b57705f4e971f14bbb0846 (clegoate/qemu-kvm-c9s)
Bugzilla: https://bugzilla.redhat.com/2192818
commit ff180c6bd7a8
Author: Avihai Horon <avihaih@nvidia.com>
Date: Mon Apr 3 16:00:00 2023 +0300
vfio/migration: Skip log_sync during migration SETUP state
Currently, VFIO log_sync can be issued while migration is in SETUP
state. However, doing this log_sync is at best redundant and at worst
can fail.
Redundant -- all RAM is marked dirty in migration SETUP state and is
transferred only after migration is set to ACTIVE state, so doing
log_sync during migration SETUP is pointless.
Can fail -- there is a time window, between setting migration state to
SETUP and starting dirty tracking by RAM save_live_setup handler, during
which dirty tracking is still not started. Any VFIO log_sync call that
is issued during this time window will fail. For example, this error can
be triggered by migrating a VM when a GUI is active, which constantly
calls log_sync.
Fix it by skipping VFIO log_sync while migration is in SETUP state.
Fixes: 758b96b61d5c ("vfio/migrate: Move switch of dirty tracking into vfio_memory_listener")
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Link: https://lore.kernel.org/r/20230403130000.6422-1-avihaih@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
hw/vfio/common.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 4d01ea3515..78358ede27 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -478,7 +478,8 @@ static bool vfio_devices_all_dirty_tracking(VFIOContainer *container)
VFIODevice *vbasedev;
MigrationState *ms = migrate_get_current();
- if (!migration_is_setup_or_active(ms->state)) {
+ if (ms->state != MIGRATION_STATUS_ACTIVE &&
+ ms->state != MIGRATION_STATUS_DEVICE) {
return false;
}
--
2.39.3