qemu-kvm/SOURCES/kvm-vfio-migration-Block-VFIO-migration-with-postcopy-migration.patch
eabdullin 214c1e4174 - dump: Add arch cleanup function
- target/s390x/arch_dump: Add arch cleanup function for PV
 dumps
- target/s390x/dump: Remove unneeded dump info function pointer
 init
2024-01-25 14:58:15 +03:00

70 lines
2.3 KiB
Diff

From bf7ef7a2da3e61dc104f26c679c9465e3fbe7dde Mon Sep 17 00:00:00 2001
From: Avihai Horon <avihaih@nvidia.com>
Date: Wed, 6 Sep 2023 18:08:52 +0300
Subject: [PATCH] vfio/migration: Block VFIO migration with postcopy migration
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
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>
---
hw/vfio/migration.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 71855468fe98..20994dc1d60b 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,