[PATCH v6 14/21] vfio/ap: Allow the selection of a given iommu backend

[Zhenzhong Duan]

Now we support two types of iommu backends, let's add the capability
to select one of them. This depends on whether an iommufd object has
been linked with the vfio-ap device:

if the user wants to use the legacy backend, it shall not
link the vfio-ap device with any iommufd object:

 -device vfio-ap,sysfsdev=/sys/bus/mdev/devices/XXX

This is called the legacy mode/backend.

If the user wants to use the iommufd backend (/dev/iommu) it
shall pass an iommufd object id in the vfio-ap device options:

 -object iommufd,id=iommufd0
 -device vfio-ap,sysfsdev=/sys/bus/mdev/devices/XXX,iommufd=iommufd0

Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
---
 hw/vfio/ap.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
index bbf69ff55a..80629609ae 100644
--- a/hw/vfio/ap.c
+++ b/hw/vfio/ap.c
@@ -11,10 +11,12 @@
  */
 
 #include "qemu/osdep.h"
+#include CONFIG_DEVICES /* CONFIG_IOMMUFD */
 #include <linux/vfio.h>
 #include <sys/ioctl.h>
 #include "qapi/error.h"
 #include "hw/vfio/vfio-common.h"
+#include "sysemu/iommufd.h"
 #include "hw/s390x/ap-device.h"
 #include "qemu/error-report.h"
 #include "qemu/event_notifier.h"
@@ -204,6 +206,10 @@ static void vfio_ap_unrealize(DeviceState *dev)
 
 static Property vfio_ap_properties[] = {
     DEFINE_PROP_STRING("sysfsdev", VFIOAPDevice, vdev.sysfsdev),
+#ifdef CONFIG_IOMMUFD
+    DEFINE_PROP_LINK("iommufd", VFIOAPDevice, vdev.iommufd,
+                     TYPE_IOMMUFD_BACKEND, IOMMUFDBackend *),
+#endif
     DEFINE_PROP_END_OF_LIST(),
 };
 
-- 
2.34.1