Michael S. Tsirkin
2023-Jul-26 18:40 UTC
[PATCH RFC net-next v5 11/14] vhost/vsock: implement datagram support
On Wed, Jul 19, 2023 at 12:50:15AM +0000, Bobby Eshleman wrote:> This commit implements datagram support for vhost/vsock by teaching > vhost to use the common virtio transport datagram functions. > > If the virtio RX buffer is too small, then the transmission is > abandoned, the packet dropped, and EHOSTUNREACH is added to the socket's > error queue. > > Signed-off-by: Bobby Eshleman <bobby.eshleman at bytedance.com>EHOSTUNREACH?> --- > drivers/vhost/vsock.c | 62 +++++++++++++++++++++++++++++++++++++++++++++--- > net/vmw_vsock/af_vsock.c | 5 +++- > 2 files changed, 63 insertions(+), 4 deletions(-) > > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c > index d5d6a3c3f273..da14260c6654 100644 > --- a/drivers/vhost/vsock.c > +++ b/drivers/vhost/vsock.c > @@ -8,6 +8,7 @@ > */ > #include <linux/miscdevice.h> > #include <linux/atomic.h> > +#include <linux/errqueue.h> > #include <linux/module.h> > #include <linux/mutex.h> > #include <linux/vmalloc.h> > @@ -32,7 +33,8 @@ > enum { > VHOST_VSOCK_FEATURES = VHOST_FEATURES | > (1ULL << VIRTIO_F_ACCESS_PLATFORM) | > - (1ULL << VIRTIO_VSOCK_F_SEQPACKET) > + (1ULL << VIRTIO_VSOCK_F_SEQPACKET) | > + (1ULL << VIRTIO_VSOCK_F_DGRAM) > }; > > enum { > @@ -56,6 +58,7 @@ struct vhost_vsock { > atomic_t queued_replies; > > u32 guest_cid; > + bool dgram_allow; > bool seqpacket_allow; > }; > > @@ -86,6 +89,32 @@ static struct vhost_vsock *vhost_vsock_get(u32 guest_cid) > return NULL; > } > > +/* Claims ownership of the skb, do not free the skb after calling! */ > +static void > +vhost_transport_error(struct sk_buff *skb, int err) > +{ > + struct sock_exterr_skb *serr; > + struct sock *sk = skb->sk; > + struct sk_buff *clone; > + > + serr = SKB_EXT_ERR(skb); > + memset(serr, 0, sizeof(*serr)); > + serr->ee.ee_errno = err; > + serr->ee.ee_origin = SO_EE_ORIGIN_NONE; > + > + clone = skb_clone(skb, GFP_KERNEL); > + if (!clone) > + return; > + > + if (sock_queue_err_skb(sk, clone)) > + kfree_skb(clone); > + > + sk->sk_err = err; > + sk_error_report(sk); > + > + kfree_skb(skb); > +} > + > static void > vhost_transport_do_send_pkt(struct vhost_vsock *vsock, > struct vhost_virtqueue *vq) > @@ -160,9 +189,15 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock, > hdr = virtio_vsock_hdr(skb); > > /* If the packet is greater than the space available in the > - * buffer, we split it using multiple buffers. > + * buffer, we split it using multiple buffers for connectible > + * sockets and drop the packet for datagram sockets. > */won't this break things like recently proposed zerocopy? I think splitup has to be supported for all types.> if (payload_len > iov_len - sizeof(*hdr)) { > + if (le16_to_cpu(hdr->type) == VIRTIO_VSOCK_TYPE_DGRAM) { > + vhost_transport_error(skb, EHOSTUNREACH); > + continue; > + } > + > payload_len = iov_len - sizeof(*hdr); > > /* As we are copying pieces of large packet's buffer to > @@ -394,6 +429,7 @@ static bool vhost_vsock_more_replies(struct vhost_vsock *vsock) > return val < vq->num; > } > > +static bool vhost_transport_dgram_allow(u32 cid, u32 port); > static bool vhost_transport_seqpacket_allow(u32 remote_cid); > > static struct virtio_transport vhost_transport = { > @@ -410,7 +446,8 @@ static struct virtio_transport vhost_transport = { > .cancel_pkt = vhost_transport_cancel_pkt, > > .dgram_enqueue = virtio_transport_dgram_enqueue, > - .dgram_allow = virtio_transport_dgram_allow, > + .dgram_allow = vhost_transport_dgram_allow, > + .dgram_addr_init = virtio_transport_dgram_addr_init, > > .stream_enqueue = virtio_transport_stream_enqueue, > .stream_dequeue = virtio_transport_stream_dequeue, > @@ -443,6 +480,22 @@ static struct virtio_transport vhost_transport = { > .send_pkt = vhost_transport_send_pkt, > }; > > +static bool vhost_transport_dgram_allow(u32 cid, u32 port) > +{ > + struct vhost_vsock *vsock; > + bool dgram_allow = false; > + > + rcu_read_lock(); > + vsock = vhost_vsock_get(cid); > + > + if (vsock) > + dgram_allow = vsock->dgram_allow; > + > + rcu_read_unlock(); > + > + return dgram_allow; > +} > + > static bool vhost_transport_seqpacket_allow(u32 remote_cid) > { > struct vhost_vsock *vsock; > @@ -799,6 +852,9 @@ static int vhost_vsock_set_features(struct vhost_vsock *vsock, u64 features) > if (features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET)) > vsock->seqpacket_allow = true; > > + if (features & (1ULL << VIRTIO_VSOCK_F_DGRAM)) > + vsock->dgram_allow = true; > + > for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) { > vq = &vsock->vqs[i]; > mutex_lock(&vq->mutex); > diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c > index e73f3b2c52f1..449ed63ac2b0 100644 > --- a/net/vmw_vsock/af_vsock.c > +++ b/net/vmw_vsock/af_vsock.c > @@ -1427,9 +1427,12 @@ int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg, > return prot->recvmsg(sk, msg, len, flags, NULL); > #endif > > - if (flags & MSG_OOB || flags & MSG_ERRQUEUE) > + if (unlikely(flags & MSG_OOB)) > return -EOPNOTSUPP; > > + if (unlikely(flags & MSG_ERRQUEUE)) > + return sock_recv_errqueue(sk, msg, len, SOL_VSOCK, 0); > + > transport = vsk->transport; > > /* Retrieve the head sk_buff from the socket's receive queue. */ > > -- > 2.30.2