[PATCH v6 6/9] vhost: always take IOTLB lock

[Xia, Chenbo]

> -----Original Message-----
> From: David Marchand <david.marchand at redhat.com>
> Sent: Tuesday, February 7, 2023 6:45 PM
> To: dev at dpdk.org
> Cc: maxime.coquelin at redhat.com; stephen at networkplumber.org; Xia, Chenbo
> <chenbo.xia at intel.com>; Hu, Jiayu <jiayu.hu at intel.com>; Wang, YuanX
> <yuanx.wang at intel.com>; Ding, Xuan <xuan.ding at intel.com>;
> mb at smartsharesystems.com
> Subject: [PATCH v6 6/9] vhost: always take IOTLB lock
> 
> clang does not support conditionally held locks when statically analysing
> taken locks with thread safety checks.
> Always take iotlb locks regardless of VIRTIO_F_IOMMU_PLATFORM feature.
> 
> Signed-off-by: David Marchand <david.marchand at redhat.com>
> Acked-by: Morten Brørup <mb at smartsharesystems.com>
> Reviewed-by: Maxime Coquelin <maxime.coquelin at redhat.com>
> ---
>  lib/vhost/vhost.c      |  8 +++-----
>  lib/vhost/virtio_net.c | 24 ++++++++----------------
>  2 files changed, 11 insertions(+), 21 deletions(-)
> 
> diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
> index 8bccdd8584..1e0c30791e 100644
> --- a/lib/vhost/vhost.c
> +++ b/lib/vhost/vhost.c
> @@ -563,10 +563,9 @@ vring_translate(struct virtio_net *dev, struct
> vhost_virtqueue *vq)
>  }
> 
>  void
> -vring_invalidate(struct virtio_net *dev, struct vhost_virtqueue *vq)
> +vring_invalidate(struct virtio_net *dev __rte_unused, struct
> vhost_virtqueue *vq)
>  {
> -	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> -		vhost_user_iotlb_wr_lock(vq);
> +	vhost_user_iotlb_wr_lock(vq);
> 
>  	vq->access_ok = false;
>  	vq->desc = NULL;
> @@ -574,8 +573,7 @@ vring_invalidate(struct virtio_net *dev, struct
> vhost_virtqueue *vq)
>  	vq->used = NULL;
>  	vq->log_guest_addr = 0;
> 
> -	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> -		vhost_user_iotlb_wr_unlock(vq);
> +	vhost_user_iotlb_wr_unlock(vq);
>  }
> 
>  static void
> diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
> index 6672caac49..49fc46e127 100644
> --- a/lib/vhost/virtio_net.c
> +++ b/lib/vhost/virtio_net.c
> @@ -1688,8 +1688,7 @@ virtio_dev_rx(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  	if (unlikely(!vq->enabled))
>  		goto out_access_unlock;
> 
> -	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> -		vhost_user_iotlb_rd_lock(vq);
> +	vhost_user_iotlb_rd_lock(vq);
> 
>  	if (unlikely(!vq->access_ok))
>  		if (unlikely(vring_translate(dev, vq) < 0))
> @@ -1707,8 +1706,7 @@ virtio_dev_rx(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  	vhost_queue_stats_update(dev, vq, pkts, nb_tx);
> 
>  out:
> -	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> -		vhost_user_iotlb_rd_unlock(vq);
> +	vhost_user_iotlb_rd_unlock(vq);
> 
>  out_access_unlock:
>  	rte_spinlock_unlock(&vq->access_lock);
> @@ -2499,8 +2497,7 @@ virtio_dev_rx_async_submit(struct virtio_net *dev,
> struct vhost_virtqueue *vq,
>  	if (unlikely(!vq->enabled || !vq->async))
>  		goto out_access_unlock;
> 
> -	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> -		vhost_user_iotlb_rd_lock(vq);
> +	vhost_user_iotlb_rd_lock(vq);
> 
>  	if (unlikely(!vq->access_ok))
>  		if (unlikely(vring_translate(dev, vq) < 0))
> @@ -2520,8 +2517,7 @@ virtio_dev_rx_async_submit(struct virtio_net *dev,
> struct vhost_virtqueue *vq,
>  	vq->stats.inflight_submitted += nb_tx;
> 
>  out:
> -	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> -		vhost_user_iotlb_rd_unlock(vq);
> +	vhost_user_iotlb_rd_unlock(vq);
> 
>  out_access_unlock:
>  	rte_spinlock_unlock(&vq->access_lock);
> @@ -3543,8 +3539,7 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
>  		goto out_access_unlock;
>  	}
> 
> -	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> -		vhost_user_iotlb_rd_lock(vq);
> +	vhost_user_iotlb_rd_lock(vq);
> 
>  	if (unlikely(!vq->access_ok))
>  		if (unlikely(vring_translate(dev, vq) < 0)) {
> @@ -3603,8 +3598,7 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
>  	vhost_queue_stats_update(dev, vq, pkts, count);
> 
>  out:
> -	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> -		vhost_user_iotlb_rd_unlock(vq);
> +	vhost_user_iotlb_rd_unlock(vq);
> 
>  out_access_unlock:
>  	rte_spinlock_unlock(&vq->access_lock);
> @@ -4150,8 +4144,7 @@ rte_vhost_async_try_dequeue_burst(int vid, uint16_t
> queue_id,
>  		goto out_access_unlock;
>  	}
> 
> -	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> -		vhost_user_iotlb_rd_lock(vq);
> +	vhost_user_iotlb_rd_lock(vq);
> 
>  	if (unlikely(vq->access_ok == 0))
>  		if (unlikely(vring_translate(dev, vq) < 0)) {
> @@ -4215,8 +4208,7 @@ rte_vhost_async_try_dequeue_burst(int vid, uint16_t
> queue_id,
>  	vhost_queue_stats_update(dev, vq, pkts, count);
> 
>  out:
> -	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> -		vhost_user_iotlb_rd_unlock(vq);
> +	vhost_user_iotlb_rd_unlock(vq);
> 
>  out_access_unlock:
>  	rte_spinlock_unlock(&vq->access_lock);
> --
> 2.39.1

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