From: Eric Auger <eric.auger@redhat.com>

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-pci device:

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

-device vfio-pci,host=0000:02:00.0

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-pci device options:

 -object iommufd,id=iommufd0
 -device vfio-pci,host=0000:02:00.0,iommufd=iommufd0

Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 hw/vfio/pci.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index d7a41c8def..386c08576a 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -43,6 +43,7 @@
 #include "migration/blocker.h"
 #include "migration/qemu-file.h"
 #include "linux/iommufd.h"
+#include "sysemu/iommufd.h"
 
 #define TYPE_VFIO_PCI_NOHOTPLUG "vfio-pci-nohotplug"
 
@@ -3710,6 +3711,10 @@ static Property vfio_pci_dev_properties[] = {
      * DEFINE_PROP_STRING("vfiofd", VFIOPCIDevice, vfiofd_name),
      * DEFINE_PROP_STRING("vfiogroupfd, VFIOPCIDevice, vfiogroupfd_name),
      */
+#ifdef CONFIG_IOMMUFD
+    DEFINE_PROP_LINK("iommufd", VFIOPCIDevice, vbasedev.iommufd,
+                     TYPE_IOMMUFD_BACKEND, IOMMUFDBackend *),
+#endif
     DEFINE_PROP_END_OF_LIST(),
 };
 
-- 
2.34.1