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

Arseniy Krasnov
2022-08-17T05:01:27Z

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