Re: [Qemu-devel] [PATCH V2 3/5] virtio-blk: disable scsi passthrough by default

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Jul 15, 2015 at 01:29:59PM +0800, Jason Wang wrote:
> Disable scsi passthrough by default since it was incompatible with
> virtio 1.0. For legacy machine types, keep this on by default.
> 
> Cc: Stefan Hajnoczi <stefanha@redhat.com>
> Cc: Kevin Wolf <kwolf@redhat.com>
> Cc: qemu-block@nongnu.org
> Signed-off-by: Jason Wang <jasowang@redhat.com>

Seems risky for 2.4.  modern is off by default for now. Can't we limit
the change to when modern is enabled?

I suggested changing this from bool to on/off/auto, and
make auto mean !modern.


> ---
>  hw/block/virtio-blk.c | 2 +-
>  include/hw/compat.h   | 6 +++++-
>  2 files changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
> index 761d763..362fe53 100644
> --- a/hw/block/virtio-blk.c
> +++ b/hw/block/virtio-blk.c
> @@ -964,7 +964,7 @@ static Property virtio_blk_properties[] = {
>      DEFINE_PROP_STRING("serial", VirtIOBlock, conf.serial),
>      DEFINE_PROP_BIT("config-wce", VirtIOBlock, conf.config_wce, 0, true),
>  #ifdef __linux__
> -    DEFINE_PROP_BIT("scsi", VirtIOBlock, conf.scsi, 0, true),
> +    DEFINE_PROP_BIT("scsi", VirtIOBlock, conf.scsi, 0, false),
>  #endif
>      DEFINE_PROP_BIT("request-merging", VirtIOBlock, conf.request_merging, 0,
>                      true),
> diff --git a/include/hw/compat.h b/include/hw/compat.h
> index 4a43466..56039d8 100644
> --- a/include/hw/compat.h
> +++ b/include/hw/compat.h
> @@ -2,7 +2,11 @@
>  #define HW_COMPAT_H
>  
>  #define HW_COMPAT_2_3 \
> -        /* empty */
> +        {\
> +            .driver   = "virtio-blk-pci",\
> +            .property = "scsi",\
> +            .value    = "on",\
> +        },
>  
>  #define HW_COMPAT_2_2 \
>          /* empty */
> -- 
> 2.1.4