RE: [RFC 08/27] vhost: add offset field to IOTLB entries

["Xia, Chenbo" <chenbo.xia@intel.com>]

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Friday, March 31, 2023 11:43 PM
> To: dev@dpdk.org; david.marchand@redhat.com; Xia, Chenbo
> <chenbo.xia@intel.com>; mkp@redhat.com; fbl@redhat.com;
> jasowang@redhat.com; Liang, Cunming <cunming.liang@intel.com>; Xie, Yongji
> <xieyongji@bytedance.com>; echaudro@redhat.com; eperezma@redhat.com;
> amorenoz@redhat.com
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> Subject: [RFC 08/27] vhost: add offset field to IOTLB entries
> 
> This patch is a preliminary work to prepare for VDUSE
> support, for which we need to keep track of the mmaped base
> address and offset in order to be able to unmap it later
> when IOTLB entry is invalidated.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  lib/vhost/iotlb.c      | 30 ++++++++++++++++++------------
>  lib/vhost/iotlb.h      |  2 +-
>  lib/vhost/vhost_user.c |  2 +-
>  3 files changed, 20 insertions(+), 14 deletions(-)
> 
> diff --git a/lib/vhost/iotlb.c b/lib/vhost/iotlb.c
> index a91115cf1c..51f118bc48 100644
> --- a/lib/vhost/iotlb.c
> +++ b/lib/vhost/iotlb.c
> @@ -17,6 +17,7 @@ struct vhost_iotlb_entry {
> 
>  	uint64_t iova;
>  	uint64_t uaddr;
> +	uint64_t uoffset;
>  	uint64_t size;
>  	uint8_t perm;
>  };
> @@ -27,15 +28,18 @@ static bool
>  vhost_user_iotlb_share_page(struct vhost_iotlb_entry *a, struct
> vhost_iotlb_entry *b,
>  		uint64_t align)
>  {
> -	uint64_t a_end, b_start;
> +	uint64_t a_start, a_end, b_start;
> 
>  	if (a == NULL || b == NULL)
>  		return false;
> 
> +	a_start = a->uaddr + a->uoffset;
> +	b_start = b->uaddr + b->uoffset;
> +
>  	/* Assumes entry a lower than entry b */
> -	RTE_ASSERT(a->uaddr < b->uaddr);
> -	a_end = RTE_ALIGN_CEIL(a->uaddr + a->size, align);
> -	b_start = RTE_ALIGN_FLOOR(b->uaddr, align);
> +	RTE_ASSERT(a_start < b_start);
> +	a_end = RTE_ALIGN_CEIL(a_start + a->size, align);
> +	b_start = RTE_ALIGN_FLOOR(b_start, align);
> 
>  	return a_end > b_start;
>  }
> @@ -43,11 +47,12 @@ vhost_user_iotlb_share_page(struct vhost_iotlb_entry
> *a, struct vhost_iotlb_entr
>  static void
>  vhost_user_iotlb_set_dump(struct virtio_net *dev, struct
> vhost_iotlb_entry *node)
>  {
> -	uint64_t align;
> +	uint64_t align, start;
> 
> -	align = hua_to_alignment(dev->mem, (void *)(uintptr_t)node->uaddr);
> +	start = node->uaddr + node->uoffset;
> +	align = hua_to_alignment(dev->mem, (void *)(uintptr_t)start);
> 
> -	mem_set_dump((void *)(uintptr_t)node->uaddr, node->size, false,
> align);
> +	mem_set_dump((void *)(uintptr_t)start, node->size, false, align);
>  }
> 
>  static void
> @@ -56,10 +61,10 @@ vhost_user_iotlb_clear_dump(struct virtio_net *dev,
> struct vhost_iotlb_entry *no
>  {
>  	uint64_t align, start, end;
> 
> -	start = node->uaddr;
> -	end = node->uaddr + node->size;
> +	start = node->uaddr + node->uoffset;
> +	end = start + node->size;
> 
> -	align = hua_to_alignment(dev->mem, (void *)(uintptr_t)node->uaddr);
> +	align = hua_to_alignment(dev->mem, (void *)(uintptr_t)start);
> 
>  	/* Skip first page if shared with previous entry. */
>  	if (vhost_user_iotlb_share_page(prev, node, align))
> @@ -234,7 +239,7 @@ vhost_user_iotlb_cache_random_evict(struct virtio_net
> *dev)
> 
>  void
>  vhost_user_iotlb_cache_insert(struct virtio_net *dev, uint64_t iova,
> uint64_t uaddr,
> -				uint64_t size, uint8_t perm)
> +				uint64_t uoffset, uint64_t size, uint8_t perm)
>  {
>  	struct vhost_iotlb_entry *node, *new_node;
> 
> @@ -256,6 +261,7 @@ vhost_user_iotlb_cache_insert(struct virtio_net *dev,
> uint64_t iova, uint64_t ua
> 
>  	new_node->iova = iova;
>  	new_node->uaddr = uaddr;
> +	new_node->uoffset = uoffset;
>  	new_node->size = size;
>  	new_node->perm = perm;
> 
> @@ -344,7 +350,7 @@ vhost_user_iotlb_cache_find(struct virtio_net *dev,
> uint64_t iova, uint64_t *siz
> 
>  		offset = iova - node->iova;
>  		if (!vva)
> -			vva = node->uaddr + offset;
> +			vva = node->uaddr + node->uoffset + offset;
> 
>  		mapped += node->size - offset;
>  		iova = node->iova + node->size;
> diff --git a/lib/vhost/iotlb.h b/lib/vhost/iotlb.h
> index 3490b9e6be..bee36c5903 100644
> --- a/lib/vhost/iotlb.h
> +++ b/lib/vhost/iotlb.h
> @@ -58,7 +58,7 @@ vhost_user_iotlb_wr_unlock_all(struct virtio_net *dev)
>  }
> 
>  void vhost_user_iotlb_cache_insert(struct virtio_net *dev, uint64_t iova,
> uint64_t uaddr,
> -					uint64_t size, uint8_t perm);
> +					uint64_t uoffset, uint64_t size, uint8_t
> perm);
>  void vhost_user_iotlb_cache_remove(struct virtio_net *dev, uint64_t iova,
> uint64_t size);
>  uint64_t vhost_user_iotlb_cache_find(struct virtio_net *dev, uint64_t
> iova,
>  					uint64_t *size, uint8_t perm);
> diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
> index 81ebef0137..93673d3902 100644
> --- a/lib/vhost/vhost_user.c
> +++ b/lib/vhost/vhost_user.c
> @@ -2641,7 +2641,7 @@ vhost_user_iotlb_msg(struct virtio_net **pdev,
>  		if (!vva)
>  			return RTE_VHOST_MSG_RESULT_ERR;
> 
> -		vhost_user_iotlb_cache_insert(dev, imsg->iova, vva, len, imsg-
> >perm);
> +		vhost_user_iotlb_cache_insert(dev, imsg->iova, vva, 0, len,
> imsg->perm);
> 
>  		for (i = 0; i < dev->nr_vring; i++) {
>  			struct vhost_virtqueue *vq = dev->virtqueue[i];
> --
> 2.39.2

Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>