vfio: don't display error if no pci devices are assigned to container

Change-Id: I21429ce084cfd39af6a9997b4c1e459f5a6ef672
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/src/vlib/linux/vfio.c b/src/vlib/linux/vfio.c
index 53eed8b..0226271 100644
--- a/src/vlib/linux/vfio.c
+++ b/src/vlib/linux/vfio.c
@@ -35,7 +35,7 @@
 linux_vfio_main_t vfio_main;
 
 static int
-map_regions (vlib_main_t * vm, int fd)
+vfio_map_regions (vlib_main_t * vm, int fd)
 {
   vlib_physmem_main_t *vpm = &physmem_main;
   linux_vfio_main_t *lvm = &vfio_main;
@@ -58,7 +58,8 @@
 	  vlib_log_debug (lvm->log_default, "map DMA va:0x%lx iova:%lx "
 			  "size:0x%lx", dm.vaddr, dm.iova, dm.size);
 
-	  if ((rv = ioctl (fd, VFIO_IOMMU_MAP_DMA, &dm)))
+	  if ((rv = ioctl (fd, VFIO_IOMMU_MAP_DMA, &dm)) &&
+	      errno != EINVAL)
 	    {
 	      vlib_log_err (lvm->log_default, "map DMA va:0x%lx iova:%lx "
 			    "size:0x%lx failed, error %s (errno %d)",
@@ -78,7 +79,7 @@
   linux_vfio_main_t *lvm = &vfio_main;
 
   if (lvm->container_fd != -1)
-    map_regions (vm, lvm->container_fd);
+    vfio_map_regions (vm, lvm->container_fd);
 }
 
 static linux_pci_vfio_iommu_group_t *