vfio/ap: Allow the selection of a given iommu backend

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>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>

diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
index bbf69ff55ae8a922d0ab6d6f966a9a2283cdd2a3..80629609aebbff9156f78c9bbde5dc6c293ac84e 100644 (file)
--- 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(),
 };