[PATCH v2 12/12] vfio: Remove 64-bit IOVA address space assumption

[Eric Auger]

Now we retrieve the usable IOVA ranges from the host,
we now the physical IOMMU aperture and we can remove
the assumption of 64b IOVA space when calling
vfio_host_win_add().

This works fine in general but in case of an IOMMU memory
region this becomes more tricky. For instance the virtio-iommu
MR has a 64b aperture by default. If the physical IOMMU has a
smaller aperture (typically the case for VTD), this means we
would need to resize the IOMMU MR when this latter is linked
to a container. However this happens on vfio_listener_region_add()
when calling the IOMMU MR set_iova_ranges() callback and this
would mean we would have a recursive call the
vfio_listener_region_add(). This looks like a wrong usage of
the memory API causing duplicate IOMMU MR notifier registration
for instance.

Until we find a better solution, make sure the vfio_find_hostwin()
is not called anymore for IOMMU region.

Signed-off-by: Eric Auger <eric.auger@redhat.com>

---

I have not found any working solution to the IOMMU MR resizing.
So I can remove this patch or remove the check for IOMMU MR. Maybe
this is an issue which can be handled separately?
---
 hw/vfio/common.c | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 26da38de05..40cac1ca91 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -1112,13 +1112,6 @@ static void vfio_listener_region_add(MemoryListener 
*listener,
 #endif
     }
 
-    hostwin = vfio_find_hostwin(container, iova, end);
-    if (!hostwin) {
-        error_setg(&err, "Container %p can't map guest IOVA region"
-                   " 0x%"HWADDR_PRIx"..0x%"HWADDR_PRIx, container, iova, end);
-        goto fail;
-    }
-
     memory_region_ref(section->mr);
 
     if (memory_region_is_iommu(section->mr)) {
@@ -1177,6 +1170,14 @@ static void vfio_listener_region_add(MemoryListener 
*listener,
         return;
     }
 
+    hostwin = vfio_find_hostwin(container, iova, end);
+    if (!hostwin) {
+        error_setg(&err, "Container %p can't map guest IOVA region"
+                   " 0x%"HWADDR_PRIx"..0x%"HWADDR_PRIx, container, iova, end);
+        goto fail;
+    }
+
+
     /* Here we assume that memory_region_is_ram(section->mr)==true */
 
     /*
@@ -2594,12 +2595,10 @@ static int vfio_connect_container(VFIOGroup *group, 
AddressSpace *as,
         vfio_get_iommu_info_migration(container, info);
         g_free(info);
 
-        /*
-         * FIXME: We should parse VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE
-         * information to get the actual window extent rather than assume
-         * a 64-bit IOVA address space.
-         */
-        vfio_host_win_add(container, 0, (hwaddr)-1, container->pgsizes);
+        g_assert(container->nr_iovas);
+        vfio_host_win_add(container, 0,
+                          container->iova_ranges[container->nr_iovas - 1].end,
+                          container->pgsizes);
 
         break;
     }
-- 
2.41.0