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authorAvihai Horon <avihaih@nvidia.com>2023-09-06 18:08:52 +0300
committerCédric Le Goater <clg@redhat.com>2023-09-11 08:34:06 +0200
commitbf7ef7a2da3e61dc104f26c679c9465e3fbe7dde (patch)
tree8ae92216df15dcd7d8a1215c298758fcad122fad /hw/vfio
parent08fc4cb51774f763dcc6fd74637aa9e00eb6a0ba (diff)
vfio/migration: Block VFIO migration with postcopy migration
VFIO migration is not compatible with postcopy migration. A VFIO device in the destination can't handle page faults for pages that have not been sent yet. Doing such migration will cause the VM to crash in the destination: qemu-system-x86_64: VFIO_MAP_DMA failed: Bad address qemu-system-x86_64: vfio_dma_map(0x55a28c7659d0, 0xc0000, 0xb000, 0x7f1b11a00000) = -14 (Bad address) qemu: hardware error: vfio: DMA mapping failed, unable to continue To prevent this, block VFIO migration with postcopy migration. Reported-by: Yanghang Liu <yanghliu@redhat.com> Signed-off-by: Avihai Horon <avihaih@nvidia.com> Tested-by: Yanghang Liu <yanghliu@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Cédric Le Goater <clg@redhat.com>
Diffstat (limited to 'hw/vfio')
-rw-r--r--hw/vfio/migration.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 71855468fe..20994dc1d6 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -335,6 +335,27 @@ static bool vfio_precopy_supported(VFIODevice *vbasedev)
/* ---------------------------------------------------------------------- */
+static int vfio_save_prepare(void *opaque, Error **errp)
+{
+ VFIODevice *vbasedev = opaque;
+
+ /*
+ * Snapshot doesn't use postcopy, so allow snapshot even if postcopy is on.
+ */
+ if (runstate_check(RUN_STATE_SAVE_VM)) {
+ return 0;
+ }
+
+ if (migrate_postcopy_ram()) {
+ error_setg(
+ errp, "%s: VFIO migration is not supported with postcopy migration",
+ vbasedev->name);
+ return -EOPNOTSUPP;
+ }
+
+ return 0;
+}
+
static int vfio_save_setup(QEMUFile *f, void *opaque)
{
VFIODevice *vbasedev = opaque;
@@ -640,6 +661,7 @@ static bool vfio_switchover_ack_needed(void *opaque)
}
static const SaveVMHandlers savevm_vfio_handlers = {
+ .save_prepare = vfio_save_prepare,
.save_setup = vfio_save_setup,
.save_cleanup = vfio_save_cleanup,
.state_pending_estimate = vfio_state_pending_estimate,