vhost-vdpa: reset vendor specific mapping to initial state in .release

Devices with on-chip IOMMU or vendor specific IOTLB implementation may
need to restore iotlb mapping to the initial or default state using the
.reset_map op, as it's desirable for some parent devices to not work
with DMA ops and maintain a simple IOMMU model with .reset_map. In
particular, device reset should not cause mapping to go away on such
IOTLB model, so persistent mapping is implied across reset. Before the
userspace process using vhost-vdpa is gone, give it a chance to reset
iotlb back to the initial state in vhost_vdpa_cleanup().

Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <1697880319-4937-3-git-send-email-si-wei.liu@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 851535f57b958937c64fdcf2465afcc2ae51bdbf..c6bfe9bdde42273e4b14be0babafa1752abc3672 100644 (file)
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -131,6 +131,15 @@ static struct vhost_vdpa_as *vhost_vdpa_find_alloc_as(struct vhost_vdpa *v,
        return vhost_vdpa_alloc_as(v, asid);
 }
 
+static void vhost_vdpa_reset_map(struct vhost_vdpa *v, u32 asid)
+{
+       struct vdpa_device *vdpa = v->vdpa;
+       const struct vdpa_config_ops *ops = vdpa->config;
+
+       if (ops->reset_map)
+               ops->reset_map(vdpa, asid);
+}
+
 static int vhost_vdpa_remove_as(struct vhost_vdpa *v, u32 asid)
 {
        struct vhost_vdpa_as *as = asid_to_as(v, asid);
@@ -140,6 +149,14 @@ static int vhost_vdpa_remove_as(struct vhost_vdpa *v, u32 asid)
 
        hlist_del(&as->hash_link);
        vhost_vdpa_iotlb_unmap(v, &as->iotlb, 0ULL, 0ULL - 1, asid);
+       /*
+        * Devices with vendor specific IOMMU may need to restore
+        * iotlb to the initial or default state, which cannot be
+        * cleaned up in the all range unmap call above. Give them
+        * a chance to clean up or reset the map to the desired
+        * state.
+        */
+       vhost_vdpa_reset_map(v, asid);
        kfree(as);
 
        return 0;