1 files changed, 18 insertions, 8 deletions

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 7c3d636025..8a8d074e18 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -363,21 +363,31 @@ bool vfio_mig_active(void)
 
 static Error *multiple_devices_migration_blocker;
 
-static unsigned int vfio_migratable_device_num(void)
+/*
+ * Multiple devices migration is allowed only if all devices support P2P
+ * migration. Single device migration is allowed regardless of P2P migration
+ * support.
+ */
+static bool vfio_multiple_devices_migration_is_supported(void)
 {
     VFIOGroup *group;
     VFIODevice *vbasedev;
     unsigned int device_num = 0;
+    bool all_support_p2p = true;
 
     QLIST_FOREACH(group, &vfio_group_list, next) {
         QLIST_FOREACH(vbasedev, &group->device_list, next) {
             if (vbasedev->migration) {
                 device_num++;
+
+                if (!(vbasedev->migration->mig_flags & VFIO_MIGRATION_P2P)) {
+                    all_support_p2p = false;
+                }
             }
         }
     }
 
-    return device_num;
+    return all_support_p2p || device_num <= 1;
 }
 
 int vfio_block_multiple_devices_migration(VFIODevice *vbasedev, Error **errp)
@@ -385,19 +395,19 @@ int vfio_block_multiple_devices_migration(VFIODevice *vbasedev, Error **errp)
     int ret;
 
     if (multiple_devices_migration_blocker ||
-        vfio_migratable_device_num() <= 1) {
+        vfio_multiple_devices_migration_is_supported()) {
         return 0;
     }
 
     if (vbasedev->enable_migration == ON_OFF_AUTO_ON) {
-        error_setg(errp, "Migration is currently not supported with multiple "
-                         "VFIO devices");
+        error_setg(errp, "Multiple VFIO devices migration is supported only if "
+                         "all of them support P2P migration");
         return -EINVAL;
     }
 
     error_setg(&multiple_devices_migration_blocker,
-               "Migration is currently not supported with multiple "
-               "VFIO devices");
+               "Multiple VFIO devices migration is supported only if all of "
+               "them support P2P migration");
     ret = migrate_add_blocker(multiple_devices_migration_blocker, errp);
     if (ret < 0) {
         error_free(multiple_devices_migration_blocker);
@@ -410,7 +420,7 @@ int vfio_block_multiple_devices_migration(VFIODevice *vbasedev, Error **errp)
 void vfio_unblock_multiple_devices_migration(void)
 {
     if (!multiple_devices_migration_blocker ||
-        vfio_migratable_device_num() > 1) {
+        !vfio_multiple_devices_migration_is_supported()) {
         return;
     }