vfio: Use vfio type1 v2 IOMMU interface

The difference between v1 and v2 is fairly subtle, simply more
deterministic behavior for unmaps.  The v1 interface allows the user
to attempt to unmap sub-regions of previous mappings, returning
success with zero size if unable to comply.  This was a reflection of
the underlying IOMMU API.  The v2 interface requires that the user
may only unmap fully contained mappings, ie. an unmap cannot intersect
or bisect a previous mapping, but may cover multiple mappings.  QEMU
never made use of the sub-region v1 support anyway, so we can support
either v1 or v2.  We'll favor v2 since it's newer.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index b230ef102bae027ce421867e1f6b288185b3868f..c5d15510dd2b653bd2eeb41a4baf36e6a3f27d3f 100644 (file)
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -662,7 +662,10 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as)
     container = g_malloc0(sizeof(*container));
     container->space = space;
     container->fd = fd;
-    if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1_IOMMU)) {
+    if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1_IOMMU) ||
+        ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1v2_IOMMU)) {
+        bool v2 = !!ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1v2_IOMMU);
+
         ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd);
         if (ret) {
             error_report("vfio: failed to set group container: %m");
@@ -670,7 +673,8 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as)
             goto free_container_exit;
         }
 
-        ret = ioctl(fd, VFIO_SET_IOMMU, VFIO_TYPE1_IOMMU);
+        ret = ioctl(fd, VFIO_SET_IOMMU,
+                    v2 ? VFIO_TYPE1v2_IOMMU : VFIO_TYPE1_IOMMU);
         if (ret) {
             error_report("vfio: failed to set iommu for container: %m");
             ret = -errno;