Re: [PATCH 5/6] virtio/vsock: add support for dgram

Bobby Eshleman
2022-08-16T16:28:33Z

CC'ing virtio-dev@lists.oasis-open.org

On Mon, Aug 15, 2022 at 10:56:08AM -0700, Bobby Eshleman wrote:
> This patch supports dgram in virtio and on the vhost side.
>
> Signed-off-by: Jiang Wang <jiang.wang@bytedance.com>
> Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
> ---
> drivers/vhost/vsock.c | 2 +-
> include/net/af_vsock.h | 2 +
> include/uapi/linux/virtio_vsock.h | 1 +
> net/vmw_vsock/af_vsock.c | 26 +++-
> net/vmw_vsock/virtio_transport.c | 2 +-
> net/vmw_vsock/virtio_transport_common.c | 173 ++++++++++++++++++++++--
> 6 files changed, 186 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> index a5d1bdb786fe..3dc72a5647ca 100644
> --- a/drivers/vhost/vsock.c
> +++ b/drivers/vhost/vsock.c
> @@ -925,7 +925,7 @@ static int __init vhost_vsock_init(void)
> int ret;
>
> ret = vsock_core_register(&vhost_transport.transport,
> - VSOCK_TRANSPORT_F_H2G);
> + VSOCK_TRANSPORT_F_H2G | VSOCK_TRANSPORT_F_DGRAM);
> if (ret < 0)
> return ret;
>
> diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
> index 1c53c4c4d88f..37e55c81e4df 100644
> --- a/include/net/af_vsock.h
> +++ b/include/net/af_vsock.h
> @@ -78,6 +78,8 @@ struct vsock_sock {
> s64 vsock_stream_has_data(struct vsock_sock *vsk);
> s64 vsock_stream_has_space(struct vsock_sock *vsk);
> struct sock *vsock_create_connected(struct sock *parent);
> +int vsock_bind_stream(struct vsock_sock *vsk,
> + struct sockaddr_vm *addr);
>
> /**** TRANSPORT ****/
>
> diff --git a/include/uapi/linux/virtio_vsock.h b/include/uapi/linux/virtio_vsock.h
> index 857df3a3a70d..0975b9c88292 100644
> --- a/include/uapi/linux/virtio_vsock.h
> +++ b/include/uapi/linux/virtio_vsock.h
> @@ -70,6 +70,7 @@ struct virtio_vsock_hdr {
> enum virtio_vsock_type {
> VIRTIO_VSOCK_TYPE_STREAM = 1,
> VIRTIO_VSOCK_TYPE_SEQPACKET = 2,
> + VIRTIO_VSOCK_TYPE_DGRAM = 3,
> };
>
> enum virtio_vsock_op {
> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> index 1893f8aafa48..87e4ae1866d3 100644
> --- a/net/vmw_vsock/af_vsock.c
> +++ b/net/vmw_vsock/af_vsock.c
> @@ -675,6 +675,19 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
> return 0;
> }
>
> +int vsock_bind_stream(struct vsock_sock *vsk,
> + struct sockaddr_vm *addr)
> +{
> + int retval;
> +
> + spin_lock_bh(&vsock_table_lock);
> + retval = __vsock_bind_connectible(vsk, addr);
> + spin_unlock_bh(&vsock_table_lock);
> +
> + return retval;
> +}
> +EXPORT_SYMBOL(vsock_bind_stream);
> +
> static int __vsock_bind_dgram(struct vsock_sock *vsk,
> struct sockaddr_vm *addr)
> {
> @@ -2363,11 +2376,16 @@ int vsock_core_register(const struct vsock_transport *t, int features)
> }
>
> if (features & VSOCK_TRANSPORT_F_DGRAM) {
> - if (t_dgram) {
> - err = -EBUSY;
> - goto err_busy;
> + /* TODO: always chose the G2H variant over others, support nesting later */
> + if (features & VSOCK_TRANSPORT_F_G2H) {
> + if (t_dgram)
> + pr_warn("virtio_vsock: t_dgram already set\n");
> + t_dgram = t;
> + }
> +
> + if (!t_dgram) {
> + t_dgram = t;
> }
> - t_dgram = t;
> }
>
> if (features & VSOCK_TRANSPORT_F_LOCAL) {
> diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
> index 073314312683..d4526ca462d2 100644
> --- a/net/vmw_vsock/virtio_transport.c
> +++ b/net/vmw_vsock/virtio_transport.c
> @@ -850,7 +850,7 @@ static int __init virtio_vsock_init(void)
> return -ENOMEM;
>
> ret = vsock_core_register(&virtio_transport.transport,
> - VSOCK_TRANSPORT_F_G2H);
> + VSOCK_TRANSPORT_F_G2H | VSOCK_TRANSPORT_F_DGRAM);
> if (ret)
> goto out_wq;
>
> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
> index bdf16fff054f..aedb48728677 100644
> --- a/net/vmw_vsock/virtio_transport_common.c
> +++ b/net/vmw_vsock/virtio_transport_common.c
> @@ -229,7 +229,9 @@ EXPORT_SYMBOL_GPL(virtio_transport_deliver_tap_pkt);
>
> static u16 virtio_transport_get_type(struct sock *sk)
> {
> - if (sk->sk_type == SOCK_STREAM)
> + if (sk->sk_type == SOCK_DGRAM)
> + return VIRTIO_VSOCK_TYPE_DGRAM;
> + else if (sk->sk_type == SOCK_STREAM)
> return VIRTIO_VSOCK_TYPE_STREAM;
> else
> return VIRTIO_VSOCK_TYPE_SEQPACKET;
> @@ -287,22 +289,29 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
> vvs = vsk->trans;
>
> /* we can send less than pkt_len bytes */
> - if (pkt_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE)
> - pkt_len = VIRTIO_VSOCK_MAX_PKT_BUF_SIZE;
> + if (pkt_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE) {
> + if (info->type != VIRTIO_VSOCK_TYPE_DGRAM)
> + pkt_len = VIRTIO_VSOCK_MAX_PKT_BUF_SIZE;
> + else
> + return 0;
> + }
>
> - /* virtio_transport_get_credit might return less than pkt_len credit */
> - pkt_len = virtio_transport_get_credit(vvs, pkt_len);
> + if (info->type != VIRTIO_VSOCK_TYPE_DGRAM) {
> + /* virtio_transport_get_credit might return less than pkt_len credit */
> + pkt_len = virtio_transport_get_credit(vvs, pkt_len);
>
> - /* Do not send zero length OP_RW pkt */
> - if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
> - return pkt_len;
> + /* Do not send zero length OP_RW pkt */
> + if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
> + return pkt_len;
> + }
>
> skb = virtio_transport_alloc_skb(info, pkt_len,
> src_cid, src_port,
> dst_cid, dst_port,
> &err);
> if (!skb) {
> - virtio_transport_put_credit(vvs, pkt_len);
> + if (info->type != VIRTIO_VSOCK_TYPE_DGRAM)
> + virtio_transport_put_credit(vvs, pkt_len);
> return err;
> }
>
> @@ -586,6 +595,61 @@ virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
> }
> EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);
>
> +static ssize_t
> +virtio_transport_dgram_do_dequeue(struct vsock_sock *vsk,
> + struct msghdr *msg, size_t len)
> +{
> + struct virtio_vsock_sock *vvs = vsk->trans;
> + struct sk_buff *skb;
> + size_t total = 0;
> + u32 free_space;
> + int err = -EFAULT;
> +
> + spin_lock_bh(&vvs->rx_lock);
> + if (total < len && !skb_queue_empty_lockless(&vvs->rx_queue)) {
> + skb = __skb_dequeue(&vvs->rx_queue);
> +
> + total = len;
> + if (total > skb->len - vsock_metadata(skb)->off)
> + total = skb->len - vsock_metadata(skb)->off;
> + else if (total < skb->len - vsock_metadata(skb)->off)
> + msg->msg_flags |= MSG_TRUNC;
> +
> + /* sk_lock is held by caller so no one else can dequeue.
> + * Unlock rx_lock since memcpy_to_msg() may sleep.
> + */
> + spin_unlock_bh(&vvs->rx_lock);
> +
> + err = memcpy_to_msg(msg, skb->data + vsock_metadata(skb)->off, total);
> + if (err)
> + return err;
> +
> + spin_lock_bh(&vvs->rx_lock);
> +
> + virtio_transport_dec_rx_pkt(vvs, skb);
> + consume_skb(skb);
> + }
> +
> + free_space = vvs->buf_alloc - (vvs->fwd_cnt - vvs->last_fwd_cnt);
> +
> + spin_unlock_bh(&vvs->rx_lock);
> +
> + if (total > 0 && msg->msg_name) {
> + /* Provide the address of the sender. */
> + DECLARE_SOCKADDR(struct sockaddr_vm *, vm_addr, msg->msg_name);
> +
> + vsock_addr_init(vm_addr, le64_to_cpu(vsock_hdr(skb)->src_cid),
> + le32_to_cpu(vsock_hdr(skb)->src_port));
> + msg->msg_namelen = sizeof(*vm_addr);
> + }
> + return total;
> +}
> +
> +static s64 virtio_transport_dgram_has_data(struct vsock_sock *vsk)
> +{
> + return virtio_transport_stream_has_data(vsk);
> +}
> +
> int
> virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,
> struct msghdr *msg,
> @@ -611,7 +675,66 @@ virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
> struct msghdr *msg,
> size_t len, int flags)
> {
> - return -EOPNOTSUPP;
> + struct sock *sk;
> + size_t err = 0;
> + long timeout;
> +
> + DEFINE_WAIT(wait);
> +
> + sk = &vsk->sk;
> + err = 0;
> +
> + if (flags & MSG_OOB || flags & MSG_ERRQUEUE || flags & MSG_PEEK)
> + return -EOPNOTSUPP;
> +
> + lock_sock(sk);
> +
> + if (!len)
> + goto out;
> +
> + timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
> +
> + while (1) {
> + s64 ready;
> +
> + prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
> + ready = virtio_transport_dgram_has_data(vsk);
> +
> + if (ready == 0) {
> + if (timeout == 0) {
> + err = -EAGAIN;
> + finish_wait(sk_sleep(sk), &wait);
> + break;
> + }
> +
> + release_sock(sk);
> + timeout = schedule_timeout(timeout);
> + lock_sock(sk);
> +
> + if (signal_pending(current)) {
> + err = sock_intr_errno(timeout);
> + finish_wait(sk_sleep(sk), &wait);
> + break;
> + } else if (timeout == 0) {
> + err = -EAGAIN;
> + finish_wait(sk_sleep(sk), &wait);
> + break;
> + }
> + } else {
> + finish_wait(sk_sleep(sk), &wait);
> +
> + if (ready < 0) {
> + err = -ENOMEM;
> + goto out;
> + }
> +
> + err = virtio_transport_dgram_do_dequeue(vsk, msg, len);
> + break;
> + }
> + }
> +out:
> + release_sock(sk);
> + return err;
> }
> EXPORT_SYMBOL_GPL(virtio_transport_dgram_dequeue);
>
> @@ -819,13 +942,13 @@ EXPORT_SYMBOL_GPL(virtio_transport_stream_allow);
> int virtio_transport_dgram_bind(struct vsock_sock *vsk,
> struct sockaddr_vm *addr)
> {
> - return -EOPNOTSUPP;
> + return vsock_bind_stream(vsk, addr);
> }
> EXPORT_SYMBOL_GPL(virtio_transport_dgram_bind);
>
> bool virtio_transport_dgram_allow(u32 cid, u32 port)
> {
> - return false;
> + return true;
> }
> EXPORT_SYMBOL_GPL(virtio_transport_dgram_allow);
>
> @@ -861,7 +984,16 @@ virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
> struct msghdr *msg,
> size_t dgram_len)
> {
> - return -EOPNOTSUPP;
> + struct virtio_vsock_pkt_info info = {
> + .op = VIRTIO_VSOCK_OP_RW,
> + .msg = msg,
> + .pkt_len = dgram_len,
> + .vsk = vsk,
> + .remote_cid = remote_addr->svm_cid,
> + .remote_port = remote_addr->svm_port,
> + };
> +
> + return virtio_transport_send_pkt_info(vsk, &info);
> }
> EXPORT_SYMBOL_GPL(virtio_transport_dgram_enqueue);
>
> @@ -1165,6 +1297,12 @@ virtio_transport_recv_connected(struct sock *sk,
> struct virtio_vsock_hdr *hdr = vsock_hdr(skb);
> int err = 0;
>
> + if (le16_to_cpu(vsock_hdr(skb)->type) == VIRTIO_VSOCK_TYPE_DGRAM) {
> + virtio_transport_recv_enqueue(vsk, skb);
> + sk->sk_data_ready(sk);
> + return err;
> + }
> +
> switch (le16_to_cpu(hdr->op)) {
> case VIRTIO_VSOCK_OP_RW:
> virtio_transport_recv_enqueue(vsk, skb);
> @@ -1320,7 +1458,8 @@ virtio_transport_recv_listen(struct sock *sk, struct sk_buff *skb,
> static bool virtio_transport_valid_type(u16 type)
> {
> return (type == VIRTIO_VSOCK_TYPE_STREAM) ||
> - (type == VIRTIO_VSOCK_TYPE_SEQPACKET);
> + (type == VIRTIO_VSOCK_TYPE_SEQPACKET) ||
> + (type == VIRTIO_VSOCK_TYPE_DGRAM);
> }
>
> /* We are under the virtio-vsock's vsock->rx_lock or vhost-vsock's vq->mutex
> @@ -1384,6 +1523,11 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
> goto free_pkt;
> }
>
> + if (sk->sk_type == SOCK_DGRAM) {
> + virtio_transport_recv_connected(sk, skb);
> + goto out;
> + }
> +
> space_available = virtio_transport_space_update(sk, skb);
>
> /* Update CID in case it has changed after a transport reset event */
> @@ -1415,6 +1559,7 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
> break;
> }
>
> +out:
> release_sock(sk);
>
> /* Release refcnt obtained when we fetched this socket out of the
> --
> 2.35.1
>