Re: [dpdk-dev] [PATCH v3] vhost: fix vhost user virtqueue not accessible

[Tiwei Bie <tiwei.bie@intel.com>]

On Wed, Oct 30, 2019 at 10:56:02PM +0800, Marvin Liu wrote:
> Log feature is disabled in vhost user, so that log address was invalid
> when checking. Check whether log address is valid can workaround it.
> Also log address should be translated in packed ring virtqueue.
> 
> Fixes: 04cfc7fdbfca ("vhost: translate incoming log address to gpa")
> 
> Signed-off-by: Marvin Liu <yong.liu@intel.com>
> ---
>  lib/librte_vhost/vhost_user.c | 30 +++++++++++++-----------------
>  1 file changed, 13 insertions(+), 17 deletions(-)
> 
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index 61ef699ac..7754d2467 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -641,11 +641,23 @@ translate_ring_addresses(struct virtio_net *dev, int vq_index)
>  	struct vhost_vring_addr *addr = &vq->ring_addrs;
>  	uint64_t len, expected_len;
>  
> +	dev = numa_realloc(dev, vq_index);

We need to update `vq->desc` first before doing numa_realloc.
https://github.com/DPDK/dpdk/blob/19397c7bf2545e6adab41b657a1f1da3c7344e7b/lib/librte_vhost/vhost_user.c#L445

> +	vq = dev->virtqueue[vq_index];
> +	if (addr->flags & (1 << VHOST_VRING_F_LOG)) {

`vq` can be reallocated by numa_realloc.
We need to update the `addr` pointer before using it.

Thanks,
Tiwei


> +		vq->log_guest_addr =
> +			translate_log_addr(dev, vq, addr->log_guest_addr);
> +		if (vq->log_guest_addr == 0) {
> +			RTE_LOG(DEBUG, VHOST_CONFIG,
> +					"(%d) failed to map log_guest_addr.\n",
> +					dev->vid);
> +			return dev;
> +		}
> +	}
> +
>  	if (vq_is_packed(dev)) {
>  		len = sizeof(struct vring_packed_desc) * vq->size;
>  		vq->desc_packed = (struct vring_packed_desc *)(uintptr_t)
>  			ring_addr_to_vva(dev, vq, addr->desc_user_addr, &len);
> -		vq->log_guest_addr = 0;
>  		if (vq->desc_packed == NULL ||
>  				len != sizeof(struct vring_packed_desc) *
>  				vq->size) {
> @@ -655,10 +667,6 @@ translate_ring_addresses(struct virtio_net *dev, int vq_index)
>  			return dev;
>  		}
>  
> -		dev = numa_realloc(dev, vq_index);
> -		vq = dev->virtqueue[vq_index];
> -		addr = &vq->ring_addrs;
> -
>  		len = sizeof(struct vring_packed_desc_event);
>  		vq->driver_event = (struct vring_packed_desc_event *)
>  					(uintptr_t)ring_addr_to_vva(dev,
> @@ -701,10 +709,6 @@ translate_ring_addresses(struct virtio_net *dev, int vq_index)
>  		return dev;
>  	}
>  
> -	dev = numa_realloc(dev, vq_index);
> -	vq = dev->virtqueue[vq_index];
> -	addr = &vq->ring_addrs;
> -
>  	len = sizeof(struct vring_avail) + sizeof(uint16_t) * vq->size;
>  	if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX))
>  		len += sizeof(uint16_t);
> @@ -741,14 +745,6 @@ translate_ring_addresses(struct virtio_net *dev, int vq_index)
>  		vq->last_avail_idx = vq->used->idx;
>  	}
>  
> -	vq->log_guest_addr =
> -		translate_log_addr(dev, vq, addr->log_guest_addr);
> -	if (vq->log_guest_addr == 0) {
> -		RTE_LOG(DEBUG, VHOST_CONFIG,
> -			"(%d) failed to map log_guest_addr .\n",
> -			dev->vid);
> -		return dev;
> -	}
>  	vq->access_ok = 1;
>  
>  	VHOST_LOG_DEBUG(VHOST_CONFIG, "(%d) mapped address desc: %p\n",
> -- 
> 2.17.1
>