diff --git a/arch/x86/kernel/pci-nommu_64.c b/arch/x86/kernel/pci-nommu_64.c
index a4e8ccf..1da9cf9 100644
--- a/arch/x86/kernel/pci-nommu_64.c
+++ b/arch/x86/kernel/pci-nommu_64.c
@@ -32,6 +32,7 @@
 	dma_addr_t bus = paddr;
 	if (!check_addr("map_single", hwdev, bus, size))
 				return bad_dma_address;
+	flush_write_buffers();
 	return bus;
 }
 
@@ -64,6 +65,7 @@
 			return 0;
 		s->dma_length = s->length;
 	}
+	flush_write_buffers();
 	return nents;
 }