intel_iommu: Add migration support with x-flts=on

When x-flts=on, we set up bindings to nested HWPT in host, after
migration, VFIO device binds to nesting parent HWPT by default.
We need to re-establish the bindings to nested HWPT, or else device
DMA will break.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20260106061304.314546-18-zhenzhong.duan@intel.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 08236b85ee67bdb41fb6a9ccbd60ac164e825064..f971cdd14c78fd80df26c0f67d4abc8cfb35645d 100644 (file)
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -4090,6 +4090,13 @@ static int vtd_post_load(void *opaque, int version_id)
      */
     vtd_switch_address_space_all(iommu);
 
+    /*
+     * Bindings to nested HWPT in host is set up dynamically depending
+     * on pasid entry configuration from guest. After migration, we
+     * need to re-establish the bindings before restoring device's DMA.
+     */
+    vtd_replay_pasid_bindings_all(iommu);
+
     return 0;
 }