Add support for kernel control to virtio-net. For the vhost-*-kernel devices, the ioctl to set the backend only provides the socket to vhost-net but does not start the handling of the virtqueues. The handling of the virtqueues is started and stopped by the kernel.
Signed-off-by: Vincent Whitchurch <[email protected]> --- drivers/vhost/net.c | 106 ++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 98 insertions(+), 8 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index b5590b7862a9..977cfa89b216 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -144,6 +144,9 @@ struct vhost_net { struct page_frag page_frag; /* Refcount bias of page frag */ int refcnt_bias; + /* Used for storing backend sockets when stopped under kernel control */ + struct socket *tx_sock; + struct socket *rx_sock; }; static unsigned vhost_net_zcopy_mask __read_mostly; @@ -1293,6 +1296,8 @@ static struct vhost_dev *vhost_net_open(struct vhost *vhost) n = kvmalloc(sizeof *n, GFP_KERNEL | __GFP_RETRY_MAYFAIL); if (!n) return ERR_PTR(-ENOMEM); + n->tx_sock = NULL; + n->rx_sock = NULL; vqs = kmalloc_array(VHOST_NET_VQ_MAX, sizeof(*vqs), GFP_KERNEL); if (!vqs) { kvfree(n); @@ -1364,6 +1369,20 @@ static struct socket *vhost_net_stop_vq(struct vhost_net *n, return sock; } +/* Stops the virtqueue but doesn't unconsume the tap ring */ +static struct socket *__vhost_net_stop_vq(struct vhost_net *n, + struct vhost_virtqueue *vq) +{ + struct socket *sock; + + mutex_lock(&vq->mutex); + sock = vhost_vq_get_backend(vq); + vhost_net_disable_vq(n, vq); + vhost_vq_set_backend(vq, NULL); + mutex_unlock(&vq->mutex); + return sock; +} + static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, struct socket **rx_sock) { @@ -1394,6 +1413,57 @@ static void vhost_net_flush(struct vhost_net *n) } } +static void vhost_net_start_vq(struct vhost_net *n, struct vhost_virtqueue *vq, + struct socket *sock) +{ + mutex_lock(&vq->mutex); + vhost_vq_set_backend(vq, sock); + vhost_vq_init_access(vq); + vhost_net_enable_vq(n, vq); + mutex_unlock(&vq->mutex); +} + +static void vhost_net_dev_start_vq(struct vhost_dev *dev, u16 idx) +{ + struct vhost_net *n = container_of(dev, struct vhost_net, dev); + + if (WARN_ON(idx >= ARRAY_SIZE(n->vqs))) + return; + + if (idx == VHOST_NET_VQ_RX) { + vhost_net_start_vq(n, &n->vqs[idx].vq, n->rx_sock); + n->rx_sock = NULL; + } else if (idx == VHOST_NET_VQ_TX) { + vhost_net_start_vq(n, &n->vqs[idx].vq, n->tx_sock); + n->tx_sock = NULL; + } + + vhost_net_flush_vq(n, idx); +} + +static void vhost_net_dev_stop_vq(struct vhost_dev *dev, u16 idx) +{ + struct vhost_net *n = container_of(dev, struct vhost_net, dev); + struct socket *sock; + + if (WARN_ON(idx >= ARRAY_SIZE(n->vqs))) + return; + + if (!vhost_vq_get_backend(&n->vqs[idx].vq)) + return; + + sock = __vhost_net_stop_vq(n, &n->vqs[idx].vq); + + vhost_net_flush(n); + synchronize_rcu(); + vhost_net_flush(n); + + if (idx == VHOST_NET_VQ_RX) + n->rx_sock = sock; + else if (idx == VHOST_NET_VQ_TX) + n->tx_sock = sock; +} + static void vhost_net_release(struct vhost_dev *dev) { struct vhost_net *n = container_of(dev, struct vhost_net, dev); @@ -1405,6 +1475,14 @@ static void vhost_net_release(struct vhost_dev *dev) vhost_dev_stop(&n->dev); vhost_dev_cleanup(&n->dev); vhost_net_vq_reset(n); + if (n->tx_sock) { + WARN_ON(tx_sock); + tx_sock = n->tx_sock; + } + if (n->rx_sock) { + WARN_ON(rx_sock); + rx_sock = n->rx_sock; + } if (tx_sock) sockfd_put(tx_sock); if (rx_sock) @@ -1518,7 +1596,7 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) mutex_lock(&vq->mutex); /* Verify that ring has been setup correctly. */ - if (!vhost_vq_access_ok(vq)) { + if (!vhost_kernel(vq) && !vhost_vq_access_ok(vq)) { r = -EFAULT; goto err_vq; } @@ -1539,14 +1617,17 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) } vhost_net_disable_vq(n, vq); - vhost_vq_set_backend(vq, sock); + if (!vhost_kernel(vq)) + vhost_vq_set_backend(vq, sock); vhost_net_buf_unproduce(nvq); - r = vhost_vq_init_access(vq); - if (r) - goto err_used; - r = vhost_net_enable_vq(n, vq); - if (r) - goto err_used; + if (!vhost_kernel(vq)) { + r = vhost_vq_init_access(vq); + if (r) + goto err_used; + r = vhost_net_enable_vq(n, vq); + if (r) + goto err_used; + } if (index == VHOST_NET_VQ_RX) nvq->rx_ring = get_tap_ptr_ring(fd); @@ -1572,6 +1653,13 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) sockfd_put(oldsock); } + if (vhost_kernel(vq)) { + if (index == VHOST_NET_VQ_TX) + n->tx_sock = sock; + else if (index == VHOST_NET_VQ_RX) + n->rx_sock = sock; + } + return 0; err_used: @@ -1733,6 +1821,8 @@ static const struct vhost_ops vhost_net_ops = { .open = vhost_net_open, .release = vhost_net_release, .ioctl = vhost_net_ioctl, + .start_vq = vhost_net_dev_start_vq, + .stop_vq = vhost_net_dev_stop_vq, }; static struct vhost *vhost_net; -- 2.28.0 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
