diff --git a/arch/x86_64/pci/mmconfig.c b/arch/x86_64/pci/mmconfig.c
index d4e25f38..b493ed9 100644
--- a/arch/x86_64/pci/mmconfig.c
+++ b/arch/x86_64/pci/mmconfig.c
@@ -75,8 +75,10 @@
 	char __iomem *addr;
 
 	/* Why do we have this when nobody checks it. How about a BUG()!? -AK */
-	if (unlikely(!value || (bus > 255) || (devfn > 255) || (reg > 4095)))
+	if (unlikely(!value || (bus > 255) || (devfn > 255) || (reg > 4095))) {
+		*value = -1;
 		return -EINVAL;
+	}
 
 	addr = pci_dev_base(seg, bus, devfn);
 	if (!addr)