[PATCH 1/2] Add serial number support for virtio_blk

[john cooper <john.cooper@xxxxxxxxxxxxxxxxxx>]

--
john.cooper@xxxxxxxxxxxxxxxxxx

 hw/virtio-blk.c |   15 ++++++++++++++-
 hw/virtio-blk.h |    3 +++
 sysemu.h        |    4 +++-
 3 files changed, 20 insertions(+), 2 deletions(-)
=================================================================
--- a/qemu/hw/virtio-blk.h
+++ b/qemu/hw/virtio-blk.h
@@ -28,6 +28,7 @@
 #define VIRTIO_BLK_F_SIZE_MAX   1       /* Indicates maximum segment size */
 #define VIRTIO_BLK_F_SEG_MAX    2       /* Indicates maximum # of segments */
 #define VIRTIO_BLK_F_GEOMETRY   4       /* Indicates support of legacy geometry */
+#define VIRTIO_BLK_F_SN		7       /* serial number supported */
 
 struct virtio_blk_config
 {
@@ -37,6 +38,8 @@ 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. */
=================================================================
--- a/qemu/hw/virtio-blk.c
+++ b/qemu/hw/virtio-blk.c
@@ -22,6 +22,7 @@ typedef struct VirtIOBlock
     BlockDriverState *bs;
     VirtQueue *vq;
     void *rq;
+    char serial_str[BLOCK_SERIAL_STRLEN + 1];
 } VirtIOBlock;
 
 static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev)
@@ -238,6 +239,8 @@ static void virtio_blk_reset(VirtIODevic
     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);
@@ -252,12 +255,17 @@ static void virtio_blk_update_config(Vir
     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)
 {
-    return (1 << VIRTIO_BLK_F_SEG_MAX | 1 << VIRTIO_BLK_F_GEOMETRY);
+    VirtIOBlock *s = to_virtio_blk(vdev);
+    char ser_set = strcmp(s->serial_str, "0");
+
+    return (1 << VIRTIO_BLK_F_SEG_MAX | 1 << VIRTIO_BLK_F_GEOMETRY |
+        (ser_set ? 1 << VIRTIO_BLK_F_SN : 0));
 }
 
 static void virtio_blk_save(QEMUFile *f, void *opaque)
@@ -298,6 +306,7 @@ void *virtio_blk_init(PCIBus *bus, Block
     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,
@@ -314,6 +323,10 @@ void *virtio_blk_init(PCIBus *bus, Block
     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->devfn = s->vdev.pci_dev.devfn;
     bdrv_guess_geometry(s->bs, &cylinders, &heads, &secs);
     bdrv_set_geometry_hint(s->bs, cylinders, heads, secs);
=================================================================
--- a/qemu/sysemu.h
+++ b/qemu/sysemu.h
@@ -133,13 +133,15 @@ typedef enum {
     BLOCK_ERR_STOP_ANY
 } BlockInterfaceErrorAction;
 
+#define BLOCK_SERIAL_STRLEN 20
+
 typedef struct DriveInfo {
     BlockDriverState *bdrv;
     BlockInterfaceType type;
     int bus;
     int unit;
     BlockInterfaceErrorAction onerror;
-    char serial[21];
+    char serial[BLOCK_SERIAL_STRLEN + 1];
     int used;
     int drive_opt_idx;
 } DriveInfo;