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

Bobby Eshleman
2022-08-17T16:24:55Z

On Wed, Aug 17, 2022 at 05:42:08AM +0000, Arseniy Krasnov wrote:
> On 17.08.2022 08:01, Arseniy Krasnov wrote:
> > On 16.08.2022 05:32, Bobby Eshleman wrote:
> >> 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.
> > Hello,
> >
> > sorry, i don't understand, how this maintains message boundaries? Or it
> > is unnecessary for SOCK_DGRAM?
> >
> > Thanks
> >>>
> >>> 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);
> ^^^
> May be, this generic data waiting logic should be in af_vsock.c, as for stream/seqpacket?
> In this way, another transport which supports SOCK_DGRAM could reuse it.

I think that is a great idea. I'll test that change for v2.

Thanks.

> >>>
> >>> @@ -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
> >>>
> >>
> >> ---------------------------------------------------------------------
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> >> For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org
> >>
> >
>