Re: [Qemu-devel] [PATCH 1.0] virtio-blk: pass full status to the guest

[Anthony Liguori]

On 11/02/2011 07:19 AM, Paolo Bonzini wrote:
> When SCSI passthrough is being used by the guest with virtio-blk, the
> guest is not able to detect disk failures.  This is because the status
> field is expected by the guest driver to include also the msg_status,
> host_status and driver_status fields, but the device is only passing
> down the SCSI status.
>
> The patch fixes this, and also makes sure that the guest always sees a
> CHECK_CONDITION status when there is valid sense data.
> ---

Applied.  Thanks.

Regards,

Anthony Liguori

>         Sorry for missing the -rc deadline, testing this requires
>         Fibre Channel stuff so I needed someone to do it for me. :)
>
>   hw/virtio-blk.c |   16 +++++++++++++++-
>   1 files changed, 15 insertions(+), 1 deletions(-)
>
> diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
> index 179747a..8beaa20 100644
> --- a/hw/virtio-blk.c
> +++ b/hw/virtio-blk.c
> @@ -16,6 +16,7 @@
>   #include "trace.h"
>   #include "blockdev.h"
>   #include "virtio-blk.h"
> +#include "scsi-defs.h"
>   #ifdef __linux__
>   # include<scsi/sg.h>
>   #endif
> @@ -231,7 +232,20 @@ static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
>           status = VIRTIO_BLK_S_OK;
>       }
>
> -    stl_p(&req->scsi->errors, hdr.status);
> +    /*
> +     * From SCSI-Generic-HOWTO: "Some lower level drivers (e.g. ide-scsi)
> +     * clear the masked_status field [hence status gets cleared too, see
> +     * block/scsi_ioctl.c] even when a CHECK_CONDITION or COMMAND_TERMINATED
> +     * status has occurred.  However they do set DRIVER_SENSE in driver_status
> +     * field. Also a (sb_len_wr>  0) indicates there is a sense buffer.
> +     */
> +    if (hdr.status == 0&&  hdr.sb_len_wr>  0) {
> +        hdr.status = CHECK_CONDITION;
> +    }
> +
> +    stl_p(&req->scsi->errors,
> +          hdr.status | (hdr.msg_status<<  8) |
> +          (hdr.host_status<<  16) | (hdr.driver_status<<  24));
>       stl_p(&req->scsi->residual, hdr.resid);
>       stl_p(&req->scsi->sense_len, hdr.sb_len_wr);
>       stl_p(&req->scsi->data_len, hdr.dxfer_len);