[RFC 12/27] vhost: add IOTLB cache entry removal callback

[Xia, Chenbo]

Hi Maxime,

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin at redhat.com>
> Sent: Friday, March 31, 2023 11:43 PM
> To: dev at dpdk.org; david.marchand at redhat.com; Xia, Chenbo
> <chenbo.xia at intel.com>; mkp at redhat.com; fbl at redhat.com;
> jasowang at redhat.com; Liang, Cunming <cunming.liang at intel.com>; Xie, Yongji
> <xieyongji at bytedance.com>; echaudro at redhat.com; eperezma at redhat.com;
> amorenoz at redhat.com
> Cc: Maxime Coquelin <maxime.coquelin at redhat.com>
> Subject: [RFC 12/27] vhost: add IOTLB cache entry removal callback
> 
> VDUSE will need to munmap() the IOTLB entry on removal
> from the cache, as it performs mmap() before insertion.
> 
> This patch introduces a callback that VDUSE layer will
> implement to achieve this.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
> ---
>  lib/vhost/iotlb.c | 12 ++++++++++++
>  lib/vhost/vhost.h |  4 ++++
>  2 files changed, 16 insertions(+)
> 
> diff --git a/lib/vhost/iotlb.c b/lib/vhost/iotlb.c
> index 188dfb8e38..86b0be62b4 100644
> --- a/lib/vhost/iotlb.c
> +++ b/lib/vhost/iotlb.c
> @@ -25,6 +25,15 @@ struct vhost_iotlb_entry {
> 
>  #define IOTLB_CACHE_SIZE 2048
> 
> +static void
> +vhost_user_iotlb_remove_notify(struct virtio_net *dev, struct
> vhost_iotlb_entry *entry)
> +{
> +	if (dev->backend_ops->iotlb_remove_notify == NULL)
> +		return;
> +
> +	dev->backend_ops->iotlb_remove_notify(entry->uaddr, entry->uoffset,
> entry->size);
> +}
> +
>  static bool
>  vhost_user_iotlb_share_page(struct vhost_iotlb_entry *a, struct
> vhost_iotlb_entry *b)
>  {
> @@ -198,6 +207,7 @@ vhost_user_iotlb_cache_remove_all(struct virtio_net
> *dev)
>  		vhost_user_iotlb_set_dump(node);
> 
>  		TAILQ_REMOVE(&dev->iotlb_list, node, next);
> +		vhost_user_iotlb_remove_notify(dev, node);
>  		vhost_user_iotlb_pool_put(dev, node);
>  	}
> 
> @@ -223,6 +233,7 @@ vhost_user_iotlb_cache_random_evict(struct virtio_net
> *dev)
>  			vhost_user_iotlb_clear_dump(node, prev_node, next_node);
> 
>  			TAILQ_REMOVE(&dev->iotlb_list, node, next);
> +			vhost_user_iotlb_remove_notify(dev, node);
>  			vhost_user_iotlb_pool_put(dev, node);
>  			dev->iotlb_cache_nr--;
>  			break;
> @@ -314,6 +325,7 @@ vhost_user_iotlb_cache_remove(struct virtio_net *dev,
> uint64_t iova, uint64_t si
>  			vhost_user_iotlb_clear_dump(node, prev_node, next_node);
> 
>  			TAILQ_REMOVE(&dev->iotlb_list, node, next);
> +			vhost_user_iotlb_remove_notify(dev, node);
>  			vhost_user_iotlb_pool_put(dev, node);
>  			dev->iotlb_cache_nr--;
>  		} else {
> diff --git a/lib/vhost/vhost.h b/lib/vhost/vhost.h
> index cc5c707205..2ad26f6951 100644
> --- a/lib/vhost/vhost.h
> +++ b/lib/vhost/vhost.h
> @@ -89,10 +89,14 @@
>  	for (iter = val; iter < num; iter++)
>  #endif
> 
> +struct virtio_net;

Adding this in patch 13 could be better since this patch is not using it.

Thanks,
Chenbo

> +typedef void (*vhost_iotlb_remove_notify)(uint64_t addr, uint64_t off,
> uint64_t size);
> +
>  /**
>   * Structure that contains backend-specific ops.
>   */
>  struct vhost_backend_ops {
> +	vhost_iotlb_remove_notify iotlb_remove_notify;
>  };
> 
>  /**
> --
> 2.39.2