Re: [PATCH v6 10/21] vfio/pci: Allow the selection of a given iommu backend

[Cédric Le Goater]

On 11/14/23 11:09, Zhenzhong Duan wrote:

From: Eric Auger <eric.au...@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.william...@redhat.com>
Signed-off-by: Eric Auger <eric.au...@redhat.com>
Signed-off-by: Yi Liu <yi.l....@intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com>

Reviewed-by: Cédric Le Goater <c...@redhat.com>

Thanks,

C.

---
  hw/vfio/pci.c | 6 ++++++
  1 file changed, 6 insertions(+)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index d00c3472c7..c5984b0598 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -19,6 +19,7 @@
   */

#include "qemu/osdep.h"

+#include CONFIG_DEVICES /* CONFIG_IOMMUFD */
  #include <linux/vfio.h>
  #include <sys/ioctl.h>

@@ -42,6 +43,7 @@

  #include "qapi/error.h"
  #include "migration/blocker.h"
  #include "migration/qemu-file.h"
+#include "sysemu/iommufd.h"

#define TYPE_VFIO_PCI_NOHOTPLUG "vfio-pci-nohotplug" @@ -3386,6 +3388,10 @@ 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(),
  };