diff --git a/hw/xen_blkif.h b/hw/xen_blkif.h
index 738b8fe..bb4ff02 100644
--- a/hw/xen_blkif.h
+++ b/hw/xen_blkif.h
@@ -16,8 +16,9 @@ struct blkif_common_response {
 	char dummy;
 };
 
+/* XXX move this into a proper header */
+#define __aligned(x)	__attribute__((__aligned__(x)))
 /* i386 protocol version */
-#pragma pack(push, 4)
 struct blkif_x86_32_request {
 	uint8_t        operation;    /* BLKIF_OP_???                         */
 	uint8_t        nr_segments;  /* number of segments                   */
@@ -25,15 +26,14 @@ struct blkif_x86_32_request {
 	uint64_t       id;           /* private guest value, echoed in resp  */
 	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
 	struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
-};
+} __aligned(4);
 struct blkif_x86_32_response {
 	uint64_t        id;              /* copied from request */
 	uint8_t         operation;       /* copied from request */
 	int16_t         status;          /* BLKIF_RSP_???       */
-};
+} __aligned(4);
 typedef struct blkif_x86_32_request blkif_x86_32_request_t;
 typedef struct blkif_x86_32_response blkif_x86_32_response_t;
-#pragma pack(pop)
 
 /* x86_64 protocol version */
 struct blkif_x86_64_request {