[Qemu-devel] Re: [PATCH 3/3] virtio block device

[Anthony Liguori]

Dor Laor wrote:
> Anthony Liguori wrote:
>
> Subject: [PATCH 3/3] virtio block device
> +
> +static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
> +{
> +    VirtIOBlock *s = to_virtio_blk(vdev);
> +    VirtQueueElement elem;
> +    unsigned int count;
> +
> +    while ((count = virtqueue_pop(vq, &elem)) != 0) {
> +       struct virtio_blk_inhdr *in;
> +       struct virtio_blk_outhdr *out;
> +       unsigned int wlen;
> +       off_t off;
> +       int i;
> +
> +       out = (void *)elem.out_sg[0].iov_base;
> +       in = (void *)elem.in_sg[elem.in_num - 1].iov_base;
> +       off = out->sector;
> +
> +       if (out->type & VIRTIO_BLK_T_SCSI_CMD) {
> +           wlen = sizeof(*in);
> +           in->status = VIRTIO_BLK_S_UNSUPP;
> +       } else if (out->type & VIRTIO_BLK_T_OUT) {
> +           wlen = sizeof(*in);
> +
> +           for (i = 1; i < elem.out_num; i++) {
> +               bdrv_write(s->bs, off,
> +                          elem.out_sg[i].iov_base,
> +                          elem.out_sg[i].iov_len / 512);
> +               off += elem.out_sg[i].iov_len / 512;
> +           }
> +
> +           in->status = VIRTIO_BLK_S_OK;
> +       } else {
> +           wlen = sizeof(*in);
> +
> +           for (i = 0; i < elem.in_num - 1; i++) {
> +               bdrv_read(s->bs, off,
> +                         elem.in_sg[i].iov_base,
> +                         elem.in_sg[i].iov_len / 512);
> +               off += elem.in_sg[i].iov_len / 512;
> +               wlen += elem.in_sg[i].iov_len;
> +           }
> +
> +           in->status = VIRTIO_BLK_S_OK;
> +       }
> +
> +       virtqueue_push(vq, &elem, wlen);
> +       virtio_notify(vdev, vq);
> +    }
>
>
>
> The notify here should also be outside the while loop.
>   

Yeah, that's in the optimization patch.

> ===================================================================
> --- qemu.orig/sysemu.h  2007-12-04 13:51:49.000000000 -0600
> +++ qemu/sysemu.h       2007-12-04 14:18:57.000000000 -0600
> @@ -117,7 +117,7 @@
>  #endif
>
>  typedef enum {
> -    IF_IDE, IF_SCSI, IF_FLOPPY, IF_PFLASH, IF_MTD, IF_SD
> +    IF_IDE, IF_SCSI, IF_FLOPPY, IF_PFLASH, IF_MTD, IF_SD, IF_VIRTIO
>  } BlockInterfaceType;
>
>  typedef struct DriveInfo {
> Index: qemu/hw/pc.c
> ===================================================================
> --- qemu.orig/hw/pc.c   2007-12-04 13:51:49.000000000 -0600
> +++ qemu/hw/pc.c        2007-12-04 14:18:57.000000000 -0600
> @@ -1008,6 +1008,18 @@
>             }
>          }
>      }
> +
> +    /* Add virtio block devices */
> +    if (pci_enabled) {
> +       int index;
> +       int unit_id = 0;
> +
> +       while ((index = drive_get_index(IF_VIRTIO, 0, unit_id)) != -1) {
> +           virtio_blk_init(pci_bus, 0x5002, 0x2258,
>
>
>
>
> The pci vendor id should be identical to the network (0x6900)
>   

Indeed!  That's for catching that.

Regards,

Anthony Liguori

> regards,
> Dor.
>