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

Arseniy Krasnov
2022-08-17T05:42:28Z

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.
>>>
>>> @@ -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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>>
>