vfio/iommufd: change process

Finish CPR by change the owning process of the iommufd device in
post load.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Link: https://lore.kernel.org/qemu-devel/1751493538-202042-19-git-send-email-steven.sistare@oracle.com
[ clg: Fixed missing "qemu/error-report.h" include ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>

Author: Steve Sistare

hw/vfio/cpr-iommufd.c

@@ -5,6 +5,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/error-report.h"
 #include "qapi/error.h"
 #include "hw/vfio/vfio-cpr.h"
 #include "hw/vfio/vfio-device.h"
@@ -112,10 +113,40 @@ static bool vfio_cpr_supported(IOMMUFDBackend *be, Error **errp)
     return true;
 }
 
+static int iommufd_cpr_pre_save(void *opaque)
+{
+    IOMMUFDBackend *be = opaque;
+
+    /*
+     * The process has not changed yet, but proactively try the ioctl,
+     * and it will fail if any DMA mappings are not supported.
+     */
+    if (!iommufd_change_process_capable(be)) {
+        error_report("some memory regions do not support "
+                     "IOMMU_IOAS_CHANGE_PROCESS");
+        return -1;
+    }
+    return 0;
+}
+
+static int iommufd_cpr_post_load(void *opaque, int version_id)
+{
+     IOMMUFDBackend *be = opaque;
+     Error *local_err = NULL;
+
+     if (!iommufd_change_process(be, &local_err)) {
+        error_report_err(local_err);
+        return -1;
+     }
+     return 0;
+}
+
 static const VMStateDescription iommufd_cpr_vmstate = {
     .name = "iommufd",
     .version_id = 0,
     .minimum_version_id = 0,
+    .pre_save = iommufd_cpr_pre_save,
+    .post_load = iommufd_cpr_post_load,
     .needed = cpr_incoming_needed,
     .fields = (VMStateField[]) {
         VMSTATE_END_OF_LIST()