diff -r ebede381efe8 tools/libxl/libxl_pci.c
--- a/tools/libxl/libxl_pci.c	Tue Jul 27 18:09:22 2010 +0100
+++ b/tools/libxl/libxl_pci.c	Fri Jul 30 15:39:41 2010 +0100
@@ -360,7 +360,7 @@
 out:
     if (!libxl_is_stubdom(ctx, domid, NULL)) {
         rc = xc_assign_device(ctx->xch, domid, pcidev->value);
-        if (rc < 0) {
+        if (rc < 0 && (hvm || ENOSYS != errno)) {
             XL_LOG_ERRNOVAL(ctx, XL_LOG_ERROR, rc, "xc_assign_device failed");
             return ERROR_FAIL;
         }
@@ -453,7 +453,7 @@
 
     if (!libxl_is_stubdom(ctx, domid, NULL)) {
         rc = xc_deassign_device(ctx->xch, domid, pcidev->value);
-        if (rc < 0)
+        if (rc < 0 && (hvm || ENOSYS != errno))
             XL_LOG_ERRNOVAL(ctx, XL_LOG_ERROR, rc, "xc_deassign_device failed");
     }