Add serial number support for virtio_blk, V3

index dad4ef0..90825a8 100644
@@ -25,6 +25,7 @@ typedef struct VirtIOBlock
     BlockDriverState *bs;
     VirtQueue *vq;
     void *rq;
+    char serial_str[BLOCK_SERIAL_STRLEN + 1];
 } VirtIOBlock;
 
 static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev)

@@ -285,6 +286,8 @@ static void virtio_blk_reset(VirtIODevice *vdev)
     qemu_aio_flush();
 }
 
+/* coalesce internal state, copy to pci i/o region 0
+ */
 static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config)
 {
     VirtIOBlock *s = to_virtio_blk(vdev);

@@ -299,11 +302,13 @@ static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config)
     stw_raw(&blkcfg.cylinders, cylinders);
     blkcfg.heads = heads;
     blkcfg.sectors = secs;
+    memcpy(&blkcfg.serial, s->serial_str, sizeof (blkcfg.serial));
     memcpy(config, &blkcfg, sizeof(blkcfg));
 }
 
 static uint32_t virtio_blk_get_features(VirtIODevice *vdev)
 {
+    VirtIOBlock *s = to_virtio_blk(vdev);
     uint32_t features = 0;
 
     features |= (1 << VIRTIO_BLK_F_SEG_MAX);

@@ -311,6 +316,8 @@ static uint32_t virtio_blk_get_features(VirtIODevice *vdev)
 #ifdef __linux__
     features |= (1 << VIRTIO_BLK_F_SCSI);
 #endif
+    if (strcmp(s->serial_str, "0"))
+        features |= 1 << VIRTIO_BLK_F_SN;
 
     return features;
 }

@@ -353,6 +360,7 @@ void *virtio_blk_init(PCIBus *bus, BlockDriverState *bs)
     VirtIOBlock *s;
     int cylinders, heads, secs;
     static int virtio_blk_id;
+    char *ps = drive_get_serial(bs);
 
     s = (VirtIOBlock *)virtio_init_pci(bus, "virtio-blk",
                                        PCI_VENDOR_ID_REDHAT_QUMRANET,

@@ -369,6 +377,10 @@ void *virtio_blk_init(PCIBus *bus, BlockDriverState *bs)
     s->vdev.reset = virtio_blk_reset;
     s->bs = bs;
     s->rq = NULL;
+    if (strlen(ps))
+        strncpy(s->serial_str, ps, sizeof (s->serial_str));
+    else
+        snprintf(s->serial_str, sizeof (s->serial_str), "0");
     bs->private = &s->vdev.pci_dev;
     bdrv_guess_geometry(s->bs, &cylinders, &heads, &secs);
     bdrv_set_geometry_hint(s->bs, cylinders, heads, secs);

index 5ef6c36..3229394 100644
@@ -31,6 +31,7 @@
 #define VIRTIO_BLK_F_RO         5       /* Disk is read-only */
 #define VIRTIO_BLK_F_BLK_SIZE   6       /* Block size of disk is available*/
 #define VIRTIO_BLK_F_SCSI       7       /* Supports scsi command passthru */
+#define VIRTIO_BLK_F_SN         8       /* serial number supported */
 
 struct virtio_blk_config
 {

@@ -40,6 +41,8 @@ struct virtio_blk_config
     uint16_t cylinders;
     uint8_t heads;
     uint8_t sectors;
+    uint32_t _blk_size;    /* structure pad, currently unused */
+    uint8_t serial[BLOCK_SERIAL_STRLEN];
 } __attribute__((packed));
 
 /* These two define direction. */

index 1f45fd6..185b4e3 100644
@@ -141,6 +141,8 @@ typedef enum {
     BLOCK_ERR_STOP_ANY
 } BlockInterfaceErrorAction;
 
+#define BLOCK_SERIAL_STRLEN 20
+
 typedef struct DriveInfo {
     BlockDriverState *bdrv;
     BlockInterfaceType type;

@@ -149,7 +151,7 @@ typedef struct DriveInfo {
     int used;
     int drive_opt_idx;
     BlockInterfaceErrorAction onerror;
-    char serial[21];
+    char serial[BLOCK_SERIAL_STRLEN + 1];
 } DriveInfo;
 
 #define MAX_IDE_DEVS	2