Re: [Qemu-devel] [PATCH 14/15] hw/block/virtio-blk: create num_queues vqs if dataplane is enabled

[Paolo Bonzini <pbonzini@redhat.com>]

Il 30/07/2014 13:39, Ming Lei ha scritto:
> Now we only support multi vqs for dataplane case.
> 
> Signed-off-by: Ming Lei <ming.lei@canonical.com>
> ---
>  hw/block/virtio-blk.c          |   18 +++++++++++++++++-
>  include/hw/virtio/virtio-blk.h |    1 +
>  2 files changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
> index ab99156..44e9956 100644
> --- a/hw/block/virtio-blk.c
> +++ b/hw/block/virtio-blk.c
> @@ -556,6 +556,7 @@ static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config)
>      blkcfg.physical_block_exp = get_physical_block_exp(s->conf);
>      blkcfg.alignment_offset = 0;
>      blkcfg.wce = bdrv_enable_write_cache(s->bs);
> +    stw_p(&blkcfg.num_queues, s->blk.num_queues);
>      memcpy(config, &blkcfg, sizeof(struct virtio_blk_config));
>  }
>  
> @@ -590,6 +591,12 @@ static uint32_t virtio_blk_get_features(VirtIODevice *vdev, uint32_t features)
>      if (bdrv_is_read_only(s->bs))
>          features |= 1 << VIRTIO_BLK_F_RO;
>  
> +#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
> +    if (s->blk.num_queues > 1) {
> +        features |= 1 << VIRTIO_BLK_F_MQ;
> +    }
> +#endif
> +
>      return features;
>  }
>  
> @@ -739,8 +746,13 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp)
>  #ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
>      Error *err = NULL;
>  #endif
> +    int i;
>      static int virtio_blk_id;
>  
> +#ifndef CONFIG_VIRTIO_BLK_DATA_PLANE
> +    blk->num_queues = 1;
> +#endif
> +
>      if (!blk->conf.bs) {
>          error_setg(errp, "drive property not set");
>          return;
> @@ -765,7 +777,10 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp)
>      s->rq = NULL;
>      s->sector_mask = (s->conf->logical_block_size / BDRV_SECTOR_SIZE) - 1;
>  
> -    s->vq = virtio_add_queue(vdev, 128, virtio_blk_handle_output);
> +    s->vqs = g_malloc0(sizeof(VirtQueue *) * blk->num_queues);
> +    for (i = 0; i < blk->num_queues; i++)
> +        s->vqs[i] = virtio_add_queue(vdev, 128, virtio_blk_handle_output);
> +    s->vq = s->vqs[0];
>      s->complete_request = virtio_blk_complete_request;
>  #ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
>      virtio_blk_data_plane_create(vdev, blk, &s->dataplane, &err);
> @@ -802,6 +817,7 @@ static void virtio_blk_device_unrealize(DeviceState *dev, Error **errp)
>      qemu_del_vm_change_state_handler(s->change);
>      unregister_savevm(dev, "virtio-blk", s);
>      blockdev_mark_auto_del(s->bs);
> +    g_free(s->vqs);
>      virtio_cleanup(vdev);
>  }
>  
> diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
> index ad70c9a..b4609dd 100644
> --- a/include/hw/virtio/virtio-blk.h
> +++ b/include/hw/virtio/virtio-blk.h
> @@ -132,6 +132,7 @@ typedef struct VirtIOBlock {
>      VirtIODevice parent_obj;
>      BlockDriverState *bs;
>      VirtQueue *vq;
> +    VirtQueue **vqs;
>      void *rq;
>      QEMUBH *bh;
>      BlockConf *conf;
> 

Dataplane must not be a change to the guest ABI.  If you implement this
feature you have to implement it for both dataplane and non-dataplne.

Paolo