Re: [Qemu-devel] [PATCH RFC] virtio: set any_layout in virtio core

[Jason Wang]

On 07/22/2015 05:36 PM, Michael S. Tsirkin wrote:
> Virtio 1 requires this, 

I think you mean transitional not virtio 1?

> and all devices are clean by now,
> so let's do it!
>
> Exceptions:
>     - virtio-blk
>     - compat machine types
>
> Signed-off-by: Michael S. Tsirkin <address@hidden>
> ---
>
> Untested - consider this pseudo-code - it just seems easier to write it
> in C than try to explain it.
>
>  include/hw/compat.h        | 22 +++++++++++++++++++++-
>  include/hw/virtio/virtio.h |  4 +++-
>  hw/block/virtio-blk.c      |  1 +
>  hw/net/virtio-net.c        |  2 --
>  hw/scsi/virtio-scsi.c      |  2 --
>  5 files changed, 25 insertions(+), 6 deletions(-)
>
> diff --git a/include/hw/compat.h b/include/hw/compat.h
> index 4a43466..94c8097 100644
> --- a/include/hw/compat.h
> +++ b/include/hw/compat.h
> @@ -2,7 +2,27 @@
>  #define HW_COMPAT_H
>  
>  #define HW_COMPAT_2_3 \
> -        /* empty */
> +        {\
> +            .driver   = "virtio-blk-pci",\
> +            .property = "any_layout",\
> +            .value    = "off",\
> +        },{\
> +            .driver   = "virtio-balloon-pci",\
> +            .property = "any_layout",\
> +            .value    = "off",\
> +        },{\
> +            .driver   = "virtio-serial-pci",\
> +            .property = "any_layout",\
> +            .value    = "off",\

In send_control_msg() it has

...
    if (!virtqueue_pop(vq, &elem)) {
        return 0;
    }

    memcpy(elem.in_sg[0].iov_base, buf, len);
...

So looks like serial is not ready for any layout.

> +        },{\
> +            .driver   = "virtio-9p-pci",\
> +            .property = "any_layout",\
> +            .value    = "off",\

In handle_9p_output() it has

...
        BUG_ON(pdu->elem.out_sg[0].iov_len < 7);
...

So looks like 9p does not support any layout at least.

> +        },{\
> +            .driver   = "virtio-rng-pci",\
> +            .property = "any_layout",\
> +            .value    = "off",\
> +        },
>  
>  #define HW_COMPAT_2_2 \
>          /* empty */
> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> index 473fb75..fbb3c06 100644
> --- a/include/hw/virtio/virtio.h
> +++ b/include/hw/virtio/virtio.h
> @@ -214,7 +214,9 @@ typedef struct VirtIORNGConf VirtIORNGConf;
>      DEFINE_PROP_BIT64("event_idx", _state, _field,        \
>                        VIRTIO_RING_F_EVENT_IDX, true),     \
>      DEFINE_PROP_BIT64("notify_on_empty", _state, _field,  \
> -                      VIRTIO_F_NOTIFY_ON_EMPTY, true)
> +                      VIRTIO_F_NOTIFY_ON_EMPTY, true) \
> +    DEFINE_PROP_BIT64("any_layout", _state, _field,  \
> +                      VIRTIO_F_ANY_LAYOUT, true)
>  
>  hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n);
>  hwaddr virtio_queue_get_avail_addr(VirtIODevice *vdev, int n);
> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
> index 6aefda4..015b9b5 100644
> --- a/hw/block/virtio-blk.c
> +++ b/hw/block/virtio-blk.c
> @@ -731,6 +731,7 @@ static uint64_t virtio_blk_get_features(VirtIODevice 
> *vdev, uint64_t features)
>      virtio_add_feature(&features, VIRTIO_BLK_F_TOPOLOGY);
>      virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE);
>      virtio_add_feature(&features, VIRTIO_BLK_F_SCSI);
> +    virtio_clear_feature(&features, VIRTIO_F_ANY_LAYOUT);
>  
>      if (s->conf.config_wce) {
>          virtio_add_feature(&features, VIRTIO_BLK_F_CONFIG_WCE);
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 304d3dd..e203058 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -1777,8 +1777,6 @@ static void virtio_net_instance_init(Object *obj)
>  }
>  
>  static Property virtio_net_properties[] = {
> -    DEFINE_PROP_BIT("any_layout", VirtIONet, host_features,
> -                    VIRTIO_F_ANY_LAYOUT, true),
>      DEFINE_PROP_BIT("csum", VirtIONet, host_features, VIRTIO_NET_F_CSUM, 
> true),
>      DEFINE_PROP_BIT("guest_csum", VirtIONet, host_features,
>                      VIRTIO_NET_F_GUEST_CSUM, true),
> diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
> index f7d3c7c..d17698d 100644
> --- a/hw/scsi/virtio-scsi.c
> +++ b/hw/scsi/virtio-scsi.c
> @@ -953,8 +953,6 @@ static Property virtio_scsi_properties[] = {
>                                                    0xFFFF),
>      DEFINE_PROP_UINT32("cmd_per_lun", VirtIOSCSI, 
> parent_obj.conf.cmd_per_lun,
>                                                    128),
> -    DEFINE_PROP_BIT("any_layout", VirtIOSCSI, host_features,
> -                                              VIRTIO_F_ANY_LAYOUT, true),
>      DEFINE_PROP_BIT("hotplug", VirtIOSCSI, host_features,
>                                             VIRTIO_SCSI_F_HOTPLUG, true),
>      DEFINE_PROP_BIT("param_change", VirtIOSCSI, host_features,