[Qemu-devel] Re: [PATCH] fix virtio_blk serial pci config breakage, v2

[Anthony Liguori <anthony@codemonkey.ws>]

john cooper wrote:
> This is a re-work of the previous version where the
> associated data was being funneled through a free
> PCI BAR mapping.  Here a request for the identify
> information results in a virtqueue command utilizing
> the scaffolding introduced by Rusty's recent patch.
>
> Signed-off-by: john cooper <john.cooper@redhat.com>
> ---
>
>
> diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
> index dad4ef0..e754277 100644
> --- a/hw/virtio-blk.c
> +++ b/hw/virtio-blk.c
> @@ -25,6 +25,7 @@ typedef struct VirtIOBlock
>     BlockDriverState *bs;
>     VirtQueue *vq;
>     void *rq;
> +    uint16_t identify[VIRTIO_BLK_ID_LEN];
> } VirtIOBlock;
>
> static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev)
> @@ -32,6 +33,48 @@ static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev)
>     return (VirtIOBlock *)vdev;
> }
>
> +/* store identify data in little endian format
> + */
> +static inline void put_le16(uint16_t *p, unsigned int v)
> +{
> +    *p = cpu_to_le16(v);
> +}
> +
> +/* copy to *dst from *src, nul pad dst tail as needed to len bytes
> + */
> +static inline void padstr(char *dst, const char *src, int len)
> +{
> +    while (len--)
> +        *dst++ = *src ? *src++ : '\0';
> +}
> +
> +/* setup simulated identify data as appropriate for virtio block device
> + *
> + * ref: AT Attachment 8 - ATA/ATAPI Command Set (ATA8-ACS)
> + */
> +static inline void virtio_identify_template(VirtIOBlock *s)
> +{
> +    uint16_t *p = s->identify;
> +    uint64_t lba_sectors;
> +
> +    memset(p, 0, sizeof(uint16_t) * VIRTIO_BLK_ID_LEN);
> +    put_le16(p + 0, 0x0);                            /* ATA device */
> +    padstr((char *)(p + 23), QEMU_VERSION, 8);       /* firmware 
> revision */
> +    padstr((char *)(p + 27), "QEMU VIRT_BLK", 40);   /* model# */
> +    put_le16(p + 47, 0x80ff);                        /* max xfer 255 
> sectors */
> +    put_le16(p + 49, 0x0b00);                        /* support 
> IORDY/LBA/DMA */
> +    put_le16(p + 59, 0x1ff);                         /* cur xfer 255 
> sectors */
> +    put_le16(p + 80, 0x1f0);                         /* support 
> ATA8/7/6/5/4 */
> +    put_le16(p + 81, 0x16);
> +    put_le16(p + 82, 0x400);
> +    put_le16(p + 83, 0x400);
> +    bdrv_get_geometry(s->bs, &lba_sectors);
> +    put_le16(p + 100, lba_sectors);
> +    put_le16(p + 101, lba_sectors >> 16);
> +    put_le16(p + 102, lba_sectors >> 32);
> +    put_le16(p + 103, lba_sectors >> 48);
> +}
> +
> typedef struct VirtIOBlockReq
> {
>     VirtIOBlock *dev;
> @@ -243,6 +286,11 @@ static void virtio_blk_handle_output(VirtIODevice 
> *vdev, VirtQueue *vq)
>
>         if (req->out->type & VIRTIO_BLK_T_SCSI_CMD) {
>             virtio_blk_handle_scsi(req);
> +        }
> +        else if (req->out->type & VIRTIO_BLK_T_GET_ID) {

CodingStyle.

> +            memcpy(req->elem.in_sg[0].iov_base, s->identify,
> +                req->elem.in_sg[0].iov_len);
> +        virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);

Weird indentation.

Regards,

Anthony Liguori