Re: [PATCH v2 6/8] vhost-user-blk: make it possible to disable write-zeroes/discard

[Raphael Norwitz]

On Fri, Aug 26, 2022 at 05:32:46PM +0300, Daniil Tatianin wrote:
> It is useful to have the ability to disable these features for
> compatibility with older VMs that don't have these implemented.
> 
> Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>

Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>

> ---
>  hw/block/vhost-user-blk.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
> index 9117222456..4c9727e08c 100644
> --- a/hw/block/vhost-user-blk.c
> +++ b/hw/block/vhost-user-blk.c
> @@ -259,8 +259,6 @@ static uint64_t vhost_user_blk_get_features(VirtIODevice 
> *vdev,
>      virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE);
>      virtio_add_feature(&features, VIRTIO_BLK_F_FLUSH);
>      virtio_add_feature(&features, VIRTIO_BLK_F_RO);
> -    virtio_add_feature(&features, VIRTIO_BLK_F_DISCARD);
> -    virtio_add_feature(&features, VIRTIO_BLK_F_WRITE_ZEROES);
>  
>      if (s->config_wce) {
>          virtio_add_feature(&features, VIRTIO_BLK_F_CONFIG_WCE);
> @@ -592,6 +590,10 @@ static Property vhost_user_blk_properties[] = {
>                         VHOST_USER_BLK_AUTO_NUM_QUEUES),
>      DEFINE_PROP_UINT32("queue-size", VHostUserBlk, queue_size, 128),
>      DEFINE_PROP_BIT("config-wce", VHostUserBlk, config_wce, 0, true),
> +    DEFINE_PROP_BIT64("discard", VHostUserBlk, parent_obj.host_features,
> +                      VIRTIO_BLK_F_DISCARD, true),
> +    DEFINE_PROP_BIT64("write-zeroes", VHostUserBlk, parent_obj.host_features,
> +                      VIRTIO_BLK_F_WRITE_ZEROES, true),
>      DEFINE_PROP_END_OF_LIST(),
>  };
>  
> -- 
> 2.25.1
>