RE: [RFC 07/27] vhost: change to single IOTLB cache per device

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

Hi Maxime,

> -----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 07/27] vhost: change to single IOTLB cache per device
> 
> This patch simplifies IOTLB implementation and improves
> IOTLB memory consumption by having a single IOTLB cache
> per device, instead of having one per queue.
> 
> In order to not impact performance, it keeps an IOTLB lock
> per virtqueue, so that there is no contention between
> multiple queue trying to acquire it.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  lib/vhost/iotlb.c      | 212 +++++++++++++++++++----------------------
>  lib/vhost/iotlb.h      |  43 ++++++---
>  lib/vhost/vhost.c      |  18 ++--
>  lib/vhost/vhost.h      |  16 ++--
>  lib/vhost/vhost_user.c |  25 +++--
>  5 files changed, 160 insertions(+), 154 deletions(-)
> 

[...]

> diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
> index d60e39b6bc..81ebef0137 100644
> --- a/lib/vhost/vhost_user.c
> +++ b/lib/vhost/vhost_user.c
> @@ -7,7 +7,7 @@
>   * The vhost-user protocol connection is an external interface, so it
> must be
>   * robust against invalid inputs.
>   *
> - * This is important because the vhost-user frontend is only one step
> removed
> +* This is important because the vhost-user frontend is only one step
> removed

This is changed by accident?

Thanks,
Chenbo

>   * from the guest.  Malicious guests that have escaped will then launch
> further
>   * attacks from the vhost-user frontend.
>   *
> @@ -237,6 +237,8 @@ vhost_backend_cleanup(struct virtio_net *dev)
>  	}
> 
>  	dev->postcopy_listening = 0;
> +
> +	vhost_user_iotlb_destroy(dev);
>  }
> 
>  static void
> @@ -539,7 +541,6 @@ numa_realloc(struct virtio_net **pdev, struct
> vhost_virtqueue **pvq)
>  	if (vq != dev->virtqueue[vq->index]) {
>  		VHOST_LOG_CONFIG(dev->ifname, INFO, "reallocated virtqueue on
> node %d\n", node);
>  		dev->virtqueue[vq->index] = vq;
> -		vhost_user_iotlb_init(dev, vq);
>  	}
> 
>  	if (vq_is_packed(dev)) {
> @@ -664,6 +665,8 @@ numa_realloc(struct virtio_net **pdev, struct
> vhost_virtqueue **pvq)
>  		return;
>  	}
>  	dev->guest_pages = gp;
> +
> +	vhost_user_iotlb_init(dev);
>  }
>  #else
>  static void
> @@ -1360,8 +1363,7 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
> 
>  		/* Flush IOTLB cache as previous HVAs are now invalid */
>  		if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> -			for (i = 0; i < dev->nr_vring; i++)
> -				vhost_user_iotlb_flush_all(dev, dev->virtqueue[i]);
> +			vhost_user_iotlb_flush_all(dev);
> 
>  		free_mem_region(dev);
>  		rte_free(dev->mem);
> @@ -2194,7 +2196,7 @@ vhost_user_get_vring_base(struct virtio_net **pdev,
>  	ctx->msg.size = sizeof(ctx->msg.payload.state);
>  	ctx->fd_num = 0;
> 
> -	vhost_user_iotlb_flush_all(dev, vq);
> +	vhost_user_iotlb_flush_all(dev);
> 
>  	vring_invalidate(dev, vq);
> 
> @@ -2639,15 +2641,14 @@ 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);
> +
>  		for (i = 0; i < dev->nr_vring; i++) {
>  			struct vhost_virtqueue *vq = dev->virtqueue[i];
> 
>  			if (!vq)
>  				continue;
> 
> -			vhost_user_iotlb_cache_insert(dev, vq, imsg->iova, vva,
> -					len, imsg->perm);
> -
>  			if (is_vring_iotlb(dev, vq, imsg)) {
>  				rte_spinlock_lock(&vq->access_lock);
>  				translate_ring_addresses(&dev, &vq);
> @@ -2657,15 +2658,14 @@ vhost_user_iotlb_msg(struct virtio_net **pdev,
>  		}
>  		break;
>  	case VHOST_IOTLB_INVALIDATE:
> +		vhost_user_iotlb_cache_remove(dev, imsg->iova, imsg->size);
> +
>  		for (i = 0; i < dev->nr_vring; i++) {
>  			struct vhost_virtqueue *vq = dev->virtqueue[i];
> 
>  			if (!vq)
>  				continue;
> 
> -			vhost_user_iotlb_cache_remove(dev, vq, imsg->iova,
> -					imsg->size);
> -
>  			if (is_vring_iotlb(dev, vq, imsg)) {
>  				rte_spinlock_lock(&vq->access_lock);
>  				vring_invalidate(dev, vq);
> @@ -2674,8 +2674,7 @@ vhost_user_iotlb_msg(struct virtio_net **pdev,
>  		}
>  		break;
>  	default:
> -		VHOST_LOG_CONFIG(dev->ifname, ERR,
> -			"invalid IOTLB message type (%d)\n",
> +		VHOST_LOG_CONFIG(dev->ifname, ERR, "invalid IOTLB message type
> (%d)\n",
>  			imsg->type);
>  		return RTE_VHOST_MSG_RESULT_ERR;
>  	}
> --
> 2.39.2