[PATCH v7 12/27] vfio/platform: 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-platform device:

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

 -device vfio-platform,host=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-platform device options:

 -object iommufd,id=iommufd0
 -device vfio-platform,host=XXX,iommufd=iommufd0

Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
---
 hw/vfio/platform.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hw/vfio/platform.c b/hw/vfio/platform.c
index 8e3d4ac458..98ae4bc655 100644
--- a/hw/vfio/platform.c
+++ b/hw/vfio/platform.c
@@ -15,11 +15,13 @@
  */
 
 #include "qemu/osdep.h"
+#include CONFIG_DEVICES /* CONFIG_IOMMUFD */
 #include "qapi/error.h"
 #include <sys/ioctl.h>
 #include <linux/vfio.h>
 
 #include "hw/vfio/vfio-platform.h"
+#include "sysemu/iommufd.h"
 #include "migration/vmstate.h"
 #include "qemu/error-report.h"
 #include "qemu/lockable.h"
@@ -649,6 +651,10 @@ static Property vfio_platform_dev_properties[] = {
     DEFINE_PROP_UINT32("mmap-timeout-ms", VFIOPlatformDevice,
                        mmap_timeout, 1100),
     DEFINE_PROP_BOOL("x-irqfd", VFIOPlatformDevice, irqfd_allowed, true),
+#ifdef CONFIG_IOMMUFD
+    DEFINE_PROP_LINK("iommufd", VFIOPlatformDevice, vbasedev.iommufd,
+                     TYPE_IOMMUFD_BACKEND, IOMMUFDBackend *),
+#endif
     DEFINE_PROP_END_OF_LIST(),
 };
 
-- 
2.34.1