/* Called with iotlb_lock read-locked */
uint64_t
__vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
uint64_t iova, uint64_t size, uint8_t perm)
{
uint64_t vva, tmp_size;
if (unlikely(!size))
return 0;
tmp_size = size;
vva = vhost_user_iotlb_cache_find(vq, iova, &tmp_size, perm);
if (tmp_size == size)
return vva;
if (!vhost_user_iotlb_pending_miss(vq, iova + tmp_size, perm)) {
/*
* iotlb_lock is read-locked for a full burst,
* but it only protects the iotlb cache.
* In case of IOTLB miss, we might block on the socket,
* which could cause a deadlock with QEMU if an IOTLB update
* is being handled. We can safely unlock here to avoid it.
*/
vhost_user_iotlb_rd_unlock(vq);
vhost_user_iotlb_pending_insert(vq, iova + tmp_size, perm);
vhost_user_iotlb_miss(dev, iova + tmp_size, perm);
vhost_user_iotlb_rd_lock(vq);
}
return 0;
}
/*
* Converts ring address to Vhost virtual address.
* If IOMMU is enabled, the ring address is a guest IO virtual address,
* else it is a QEMU virtual address.
*/
static uint64_t
ring_addr_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
uint64_t ra, uint64_t *size)
{
if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)) {
uint64_t vva;
vva = vhost_user_iotlb_cache_find(vq, ra,
size, VHOST_ACCESS_RW);
if (!vva)
vhost_user_iotlb_miss(dev, ra, VHOST_ACCESS_RW);
return vva;
}
return qva_to_vva(dev, ra, size);
}