diff --git a/hw/device-assignment.c b/hw/device-assignment.c
index c4c2535..d586ce4 100644
--- a/hw/device-assignment.c
+++ b/hw/device-assignment.c
@@ -618,8 +618,9 @@
              * kernels return EIO.  New kernels only allow 1/2/4 byte reads
              * so should return EINVAL for a 3 byte read */
             ret = pread(pci_dev->v_addrs[i].region->resource_fd, &val, 3, 0);
-            if (ret == 3) {
-                fprintf(stderr, "I/O port resource supports 3 byte read?!\n");
+            if (ret >= 0) {
+                fprintf(stderr, "Unexpected return from I/O port read: %d\n",
+                        ret);
                 abort();
             } else if (errno != EINVAL) {
                 fprintf(stderr, "Using raw in/out ioport access (sysfs - %s)\n",