vfio/migration: Change vIOMMU blocker from global to per device

Contrary to multiple device blocker which needs to consider already-attached
devices to unblock/block dynamically, the vIOMMU migration blocker is a device
specific config. Meaning it only needs to know whether the device is bypassing
or not the vIOMMU (via machine property, or per pxb-pcie::bypass_iommu), and
does not need the state of currently present devices. For this reason, the
vIOMMU global migration blocker can be consolidated into the per-device
migration blocker, allowing us to remove some unnecessary code.

This change also makes vfio_mig_active() more accurate as it doesn't check for
global blocker.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 1db7d52ab2..e6e5e85f75 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -878,9 +878,10 @@ int vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
         return ret;
     }
 
-    ret = vfio_block_giommu_migration(vbasedev, errp);
-    if (ret) {
-        return ret;
+    if (vfio_viommu_preset(vbasedev)) {
+        error_setg(&err, "%s: Migration is currently not supported "
+                   "with vIOMMU enabled", vbasedev->name);
+        return vfio_block_migration(vbasedev, err, errp);
     }
 
     trace_vfio_migration_realize(vbasedev->name);