Re: [RFC PATCH v6 00/22] virtio/vsock: introduce SOCK_SEQPACKET support

Re: [RFC PATCH v6 00/22] virtio/vsock: introduce SOCK_SEQPACKET support

[Stefano Garzarella]

Hi Arseny,
thanks for this new version.

It's a busy week for me, but I hope to review this series by the end of 
this week :-)

Thanks,
Stefano

On Sun, Mar 07, 2021 at 08:57:19PM +0300, Arseny Krasnov wrote:
>	This patchset implements support of SOCK_SEQPACKET for virtio
>transport.
>	As SOCK_SEQPACKET guarantees to save record boundaries, so to
>do it, two new packet operations were added: first for start of record
> and second to mark end of record(SEQ_BEGIN and SEQ_END later). Also,
>both operations carries metadata - to maintain boundaries and payload
>integrity. Metadata is introduced by adding special header with two
>fields - message id and message length:
>
>	struct virtio_vsock_seq_hdr {
>		__le32  msg_id;
>		__le32  msg_len;
>	} __attribute__((packed));
>
>	This header is transmitted as payload of SEQ_BEGIN and SEQ_END
>packets(buffer of second virtio descriptor in chain) in the same way as
>data transmitted in RW packets. Payload was chosen as buffer for this
>header to avoid touching first virtio buffer which carries header of
>packet, because someone could check that size of this buffer is equal
>to size of packet header. To send record, packet with start marker is
>sent first(it's header carries length of record and id),then all data
>is sent as usual 'RW' packets and finally SEQ_END is sent(it carries
>id of message, which is equal to id of SEQ_BEGIN), also after sending
>SEQ_END id is incremented. On receiver's side,size of record is known
>from packet with start record marker. To check that no packets were
>dropped by transport, 'msg_id's of two sequential SEQ_BEGIN and SEQ_END
>are checked to be equal and length of data between two markers is
>compared to then length in SEQ_BEGIN header.
>	Now as  packets of one socket are not reordered neither on
>vsock nor on vhost transport layers, such markers allows to restore
>original record on receiver's side. If user's buffer is smaller that
>record length, when all out of size data is dropped.
>	Maximum length of datagram is not limited as in stream socket,
>because same credit logic is used. Difference with stream socket is
>that user is not woken up until whole record is received or error
>occurred. Implementation also supports 'MSG_EOR' and 'MSG_TRUNC' flags.
>	Tests also implemented.
>
>	Thanks to stsp2@yandex.ru for encouragements and initial design
>recommendations.
>
> Arseny Krasnov (22):
>  af_vsock: update functions for connectible socket
>  af_vsock: separate wait data loop
>  af_vsock: separate receive data loop
>  af_vsock: implement SEQPACKET receive loop
>  af_vsock: separate wait space loop
>  af_vsock: implement send logic for SEQPACKET
>  af_vsock: rest of SEQPACKET support
>  af_vsock: update comments for stream sockets
>  virtio/vsock: set packet's type in virtio_transport_send_pkt_info()
>  virtio/vsock: simplify credit update function API
>  virtio/vsock: dequeue callback for SOCK_SEQPACKET
>  virtio/vsock: fetch length for SEQPACKET record
>  virtio/vsock: add SEQPACKET receive logic
>  virtio/vsock: rest of SOCK_SEQPACKET support
>  virtio/vsock: SEQPACKET feature bit
>  vhost/vsock: SEQPACKET feature bit support
>  virtio/vsock: SEQPACKET feature bit support
>  virtio/vsock: setup SEQPACKET ops for transport
>  vhost/vsock: setup SEQPACKET ops for transport
>  vsock/loopback: setup SEQPACKET ops for transport
>  vsock_test: add SOCK_SEQPACKET tests
>  virtio/vsock: update trace event for SEQPACKET
>
> drivers/vhost/vsock.c                        |  22 +-
> include/linux/virtio_vsock.h                 |  22 +
> include/net/af_vsock.h                       |  10 +
> .../events/vsock_virtio_transport_common.h   |  48 +-
> include/uapi/linux/virtio_vsock.h            |  19 +
> net/vmw_vsock/af_vsock.c                     | 589 +++++++++++------
> net/vmw_vsock/virtio_transport.c             |  18 +
> net/vmw_vsock/virtio_transport_common.c      | 364 ++++++++--
> net/vmw_vsock/vsock_loopback.c               |  13 +
> tools/testing/vsock/util.c                   |  32 +-
> tools/testing/vsock/util.h                   |   3 +
> tools/testing/vsock/vsock_test.c             | 126 ++++
> 12 files changed, 1013 insertions(+), 253 deletions(-)
>
> v5 -> v6:
> General changelog:
> - virtio transport specific callbacks which send SEQ_BEGIN or
>   SEQ_END now hidden inside virtio transport. Only enqueue,
>   dequeue and record length callbacks are provided by transport.
>
> - virtio feature bit for SEQPACKET socket support introduced:
>   VIRTIO_VSOCK_F_SEQPACKET.
>
> - 'msg_cnt' field in 'struct virtio_vsock_seq_hdr' renamed to
>   'msg_id' and used as id.
>
> Per patch changelog:
> - 'af_vsock: separate wait data loop':
>    1) Commit message updated.
>    2) 'prepare_to_wait()' moved inside while loop(thanks to
>      Jorgen Hansen).
>    Marked 'Reviewed-by' with 1), but as 2) I removed R-b.
>
> - 'af_vsock: separate receive data loop': commit message
>    updated.
>    Marked 'Reviewed-by' with that fix.
>
> - 'af_vsock: implement SEQPACKET receive loop': style fixes.
>
> - 'af_vsock: rest of SEQPACKET support':
>    1) 'module_put()' added when transport callback check failed.
>    2) Now only 'seqpacket_allow()' callback called to check
>       support of SEQPACKET by transport.
>
> - 'af_vsock: update comments for stream sockets': commit message
>    updated.
>    Marked 'Reviewed-by' with that fix.
>
> - 'virtio/vsock: set packet's type in send':
>    1) Commit message updated.
>    2) Parameter 'type' from 'virtio_transport_send_credit_update()'
>       also removed in this patch instead of in next.
>
> - 'virtio/vsock: dequeue callback for SOCK_SEQPACKET': SEQPACKET
>    related state wrapped to special struct.
>
> - 'virtio/vsock: update trace event for SEQPACKET': format strings
>    now not broken by new lines.
>
> v4 -> v5:
> - patches reorganized:
>   1) Setting of packet's type in 'virtio_transport_send_pkt_info()'
>      is moved to separate patch.
>   2) Simplifying of 'virtio_transport_send_credit_update()' is
>      moved to separate patch and before main virtio/vsock patches.
> - style problem fixed
> - in 'af_vsock: separate receive data loop' extra 'release_sock()'
>   removed
> - added trace event fields for SEQPACKET
> - in 'af_vsock: separate wait data loop':
>   1) 'vsock_wait_data()' removed 'goto out;'
>   2) Comment for invalid data amount is changed.
> - in 'af_vsock: rest of SEQPACKET support', 'new_transport' pointer
>   check is moved after 'try_module_get()'
> - in 'af_vsock: update comments for stream sockets', 'connect-oriented'
>   replaced with 'connection-oriented'
> - in 'loopback/vsock: setup SEQPACKET ops for transport',
>   'loopback/vsock' replaced with 'vsock/loopback'
>
> v3 -> v4:
> - SEQPACKET specific metadata moved from packet header to payload
>   and called 'virtio_vsock_seq_hdr'
> - record integrity check:
>   1) SEQ_END operation was added, which marks end of record.
>   2) Both SEQ_BEGIN and SEQ_END carries counter which is incremented
>      on every marker send.
> - af_vsock.c: socket operations for STREAM and SEQPACKET call same
>   functions instead of having own "gates" differs only by names:
>   'vsock_seqpacket/stream_getsockopt()' now replaced with
>   'vsock_connectible_getsockopt()'.
> - af_vsock.c: 'seqpacket_dequeue' callback returns error and flag that
>   record ready. There is no need to return number of copied bytes,
>   because case when record received successfully is checked at virtio
>   transport layer, when SEQ_END is processed. Also user doesn't need
>   number of copied bytes, because 'recv()' from SEQPACKET could return
>   error, length of users's buffer or length of whole record(both are
>   known in af_vsock.c).
> - af_vsock.c: both wait loops in af_vsock.c(for data and space) moved
>   to separate functions because now both called from several places.
> - af_vsock.c: 'vsock_assign_transport()' checks that 'new_transport'
>   pointer is not NULL and returns 'ESOCKTNOSUPPORT' instead of 'ENODEV'
>   if failed to use transport.
> - tools/testing/vsock/vsock_test.c: rename tests
>
> v2 -> v3:
> - patches reorganized: split for prepare and implementation patches
> - local variables are declared in "Reverse Christmas tree" manner
> - virtio_transport_common.c: valid leXX_to_cpu() for vsock header
>   fields access
> - af_vsock.c: 'vsock_connectible_*sockopt()' added as shared code
>   between stream and seqpacket sockets.
> - af_vsock.c: loops in '__vsock_*_recvmsg()' refactored.
> - af_vsock.c: 'vsock_wait_data()' refactored.
>
> v1 -> v2:
> - patches reordered: af_vsock.c related changes now before virtio vsock
> - patches reorganized: more small patches, where +/- are not mixed
> - tests for SOCK_SEQPACKET added
> - all commit messages updated
> - af_vsock.c: 'vsock_pre_recv_check()' inlined to
>   'vsock_connectible_recvmsg()'
> - af_vsock.c: 'vsock_assign_transport()' returns ENODEV if transport
>   was not found
> - virtio_transport_common.c: transport callback for seqpacket dequeue
> - virtio_transport_common.c: simplified
>   'virtio_transport_recv_connected()'
> - virtio_transport_common.c: send reset on socket and packet type
>			      mismatch.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>
>-- 
>2.25.1
>

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Re: [RFC PATCH v6 01/22] af_vsock: update functions for connectible socket

[Stefano Garzarella]

On Sun, Mar 07, 2021 at 08:58:39PM +0300, Arseny Krasnov wrote:
>This prepares af_vsock.c for SEQPACKET support: some functions such
>as setsockopt(), getsockopt(), connect(), recvmsg(), sendmsg() are
>shared between both types of sockets, so rename them in general
>manner.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> net/vmw_vsock/af_vsock.c | 64 +++++++++++++++++++++-------------------
> 1 file changed, 34 insertions(+), 30 deletions(-)

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

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Re: [RFC PATCH v6 02/22] af_vsock: separate wait data loop

[Stefano Garzarella]

On Sun, Mar 07, 2021 at 08:59:01PM +0300, Arseny Krasnov wrote:
>This moves wait loop for data to dedicated function, because later it
>will be used by SEQPACKET data receive loop. While moving the code
>around, let's update an old comment.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> net/vmw_vsock/af_vsock.c | 156 +++++++++++++++++++++------------------
> 1 file changed, 84 insertions(+), 72 deletions(-)

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

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Re: [RFC PATCH v6 04/22] af_vsock: implement SEQPACKET receive loop

[Stefano Garzarella]

On Sun, Mar 07, 2021 at 08:59:45PM +0300, Arseny Krasnov wrote:
>This adds receive loop for SEQPACKET. It looks like receive loop for
>STREAM, but there is a little bit difference:
>1) It doesn't call notify callbacks.
>2) It doesn't care about 'SO_SNDLOWAT' and 'SO_RCVLOWAT' values, because
>   there is no sense for these values in SEQPACKET case.
>3) It waits until whole record is received or error is found during
>   receiving.
>4) It processes and sets 'MSG_TRUNC' flag.
>
>So to avoid extra conditions for two types of socket inside one loop, two
>independent functions were created.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> include/net/af_vsock.h   |  5 +++
> net/vmw_vsock/af_vsock.c | 95 +++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 99 insertions(+), 1 deletion(-)

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

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Re: [RFC PATCH v6 06/22] af_vsock: implement send logic for SEQPACKET

[Stefano Garzarella]

On Sun, Mar 07, 2021 at 09:00:26PM +0300, Arseny Krasnov wrote:
>This adds some logic to current stream enqueue function for SEQPACKET
>support:
>1) Use transport's seqpacket enqueue callback.
>2) Return value from enqueue function is whole record length or error
>   for SOCK_SEQPACKET.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> include/net/af_vsock.h   |  2 ++
> net/vmw_vsock/af_vsock.c | 22 ++++++++++++++++------
> 2 files changed, 18 insertions(+), 6 deletions(-)
>
>diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
>index a8c4039e40cf..aed306292ab3 100644
>--- a/include/net/af_vsock.h
>+++ b/include/net/af_vsock.h
>@@ -139,6 +139,8 @@ struct vsock_transport {
> 	size_t (*seqpacket_seq_get_len)(struct vsock_sock *vsk);
> 	int (*seqpacket_dequeue)(struct vsock_sock *vsk, struct msghdr *msg,
> 				 int flags, bool *msg_ready);
>+	int (*seqpacket_enqueue)(struct vsock_sock *vsk, struct msghdr *msg,
>+				 int flags, size_t len);
>
> 	/* Notification. */
> 	int (*notify_poll_in)(struct vsock_sock *, size_t, bool *);
>diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>index 5bf64a3e678a..a031f165494d 100644
>--- a/net/vmw_vsock/af_vsock.c
>+++ b/net/vmw_vsock/af_vsock.c
>@@ -1830,9 +1830,14 @@ static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,
> 		 * responsibility to check how many bytes we were able to send.
> 		 */
>
>-		written = transport->stream_enqueue(
>-				vsk, msg,
>-				len - total_written);
>+		if (sk->sk_type == SOCK_SEQPACKET) {
>+			written = transport->seqpacket_enqueue(vsk,
>+						msg, msg->msg_flags,

I think we can avoid to pass 'msg->msg_flags', since the transport can 
access it through the 'msg' pointer, right?

>+						len - total_written);
>+		} else {
>+			written = transport->stream_enqueue(vsk,
>+					msg, len - total_written);
>+		}
> 		if (written < 0) {
> 			err = -ENOMEM;
> 			goto out_err;
>@@ -1844,12 +1849,17 @@ static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,
> 				vsk, written, &send_data);
> 		if (err < 0)
> 			goto out_err;
>-
> 	}
>
> out_err:
>-	if (total_written > 0)
>-		err = total_written;
>+	if (total_written > 0) {
>+		/* Return number of written bytes only if:
>+		 * 1) SOCK_STREAM socket.
>+		 * 2) SOCK_SEQPACKET socket when whole buffer is sent.
>+		 */
>+		if (sk->sk_type == SOCK_STREAM || total_written == len)
>+			err = total_written;
>+	}
> out:
> 	release_sock(sk);
> 	return err;
>-- 
>2.25.1
>

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Re: [RFC PATCH v6 04/22] af_vsock: implement SEQPACKET receive loop

[Stefano Garzarella]

On Sun, Mar 07, 2021 at 08:59:45PM +0300, Arseny Krasnov wrote:
>This adds receive loop for SEQPACKET. It looks like receive loop for
>STREAM, but there is a little bit difference:
>1) It doesn't call notify callbacks.
>2) It doesn't care about 'SO_SNDLOWAT' and 'SO_RCVLOWAT' values, because
>   there is no sense for these values in SEQPACKET case.
>3) It waits until whole record is received or error is found during
>   receiving.
>4) It processes and sets 'MSG_TRUNC' flag.
>
>So to avoid extra conditions for two types of socket inside one loop, two
>independent functions were created.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> include/net/af_vsock.h   |  5 +++
> net/vmw_vsock/af_vsock.c | 95 +++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 99 insertions(+), 1 deletion(-)
>
>diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
>index b1c717286993..5ad7ee7f78fd 100644
>--- a/include/net/af_vsock.h
>+++ b/include/net/af_vsock.h
>@@ -135,6 +135,11 @@ struct vsock_transport {
> 	bool (*stream_is_active)(struct vsock_sock *);
> 	bool (*stream_allow)(u32 cid, u32 port);
>
>+	/* SEQ_PACKET. */
>+	size_t (*seqpacket_seq_get_len)(struct vsock_sock *vsk);
>+	int (*seqpacket_dequeue)(struct vsock_sock *vsk, struct msghdr *msg,
>+				 int flags, bool *msg_ready);
>+
> 	/* Notification. */
> 	int (*notify_poll_in)(struct vsock_sock *, size_t, bool *);
> 	int (*notify_poll_out)(struct vsock_sock *, size_t, bool *);
>diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>index 0bc661e54262..ac2f69362f2e 100644
>--- a/net/vmw_vsock/af_vsock.c
>+++ b/net/vmw_vsock/af_vsock.c
>@@ -1973,6 +1973,96 @@ static int __vsock_stream_recvmsg(struct sock *sk, struct msghdr *msg,
> 	return err;
> }
>
>+static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
>+				     size_t len, int flags)
>+{
>+	const struct vsock_transport *transport;
>+	const struct iovec *orig_iov;
>+	unsigned long orig_nr_segs;
>+	bool msg_ready;
>+	struct vsock_sock *vsk;
>+	size_t record_len;
>+	long timeout;
>+	int err = 0;
>+	DEFINE_WAIT(wait);
>+
>+	vsk = vsock_sk(sk);
>+	transport = vsk->transport;
>+
>+	timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
>+	orig_nr_segs = msg->msg_iter.nr_segs;
>+	orig_iov = msg->msg_iter.iov;
>+	msg_ready = false;
>+	record_len = 0;
>+
>+	while (1) {
>+		err = vsock_wait_data(sk, &wait, timeout, NULL, 0);
>+
>+		if (err <= 0) {
>+			/* In case of any loop break(timeout, signal
>+			 * interrupt or shutdown), we report user that
>+			 * nothing was copied.
>+			 */
>+			err = 0;
>+			break;
>+		}
>+
>+		if (record_len == 0) {
>+			record_len =
>+				transport->seqpacket_seq_get_len(vsk);
>+
>+			if (record_len == 0)
>+				continue;
>+		}
>+
>+		err = transport->seqpacket_dequeue(vsk, msg, flags, &msg_ready);

In order to simplify the transport interface, can we do the work of 
seqpacket_seq_get_len() at the beginning of seqpacket_dequeue()?

So in this way seqpacket_dequeue() can return the 'record_len' or an 
error.

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Re: [RFC PATCH v6 12/22] virtio/vsock: fetch length for SEQPACKET record

[Stefano Garzarella]

On Sun, Mar 07, 2021 at 09:02:31PM +0300, Arseny Krasnov wrote:
>This adds transport callback which tries to fetch record begin marker
>from socket's rx queue. It is called from af_vsock.c before reading data
>packets of record.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> include/linux/virtio_vsock.h            |  1 +
> net/vmw_vsock/virtio_transport_common.c | 53 +++++++++++++++++++++++++
> 2 files changed, 54 insertions(+)
>
>diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>index 466a5832d2f5..d7edcfeb4cd2 100644
>--- a/include/linux/virtio_vsock.h
>+++ b/include/linux/virtio_vsock.h
>@@ -88,6 +88,7 @@ virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
> 			       struct msghdr *msg,
> 			       size_t len, int flags);
>
>+size_t virtio_transport_seqpacket_seq_get_len(struct vsock_sock *vsk);
> int
> virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
> 				   struct msghdr *msg,
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index 5f1e283e43f3..6fc78fec41c0 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -399,6 +399,59 @@ static inline void virtio_transport_remove_pkt(struct virtio_vsock_pkt *pkt)
> 	virtio_transport_free_pkt(pkt);
> }
>
>+static size_t virtio_transport_drop_until_seq_begin(struct virtio_vsock_sock *vvs)
>+{
>+	struct virtio_vsock_pkt *pkt, *n;
>+	size_t bytes_dropped = 0;
>+
>+	list_for_each_entry_safe(pkt, n, &vvs->rx_queue, list) {
>+		if (le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_SEQ_BEGIN)
>+			break;
>+
>+		bytes_dropped += le32_to_cpu(pkt->hdr.len);
>+		virtio_transport_dec_rx_pkt(vvs, pkt);
>+		virtio_transport_remove_pkt(pkt);
>+	}
>+
>+	return bytes_dropped;
>+}
>+
>+size_t virtio_transport_seqpacket_seq_get_len(struct vsock_sock *vsk)
>+{
>+	struct virtio_vsock_seq_hdr *seq_hdr;
>+	struct virtio_vsock_sock *vvs;
>+	struct virtio_vsock_pkt *pkt;
>+	size_t bytes_dropped;
>+
>+	vvs = vsk->trans;
>+
>+	spin_lock_bh(&vvs->rx_lock);
>+
>+	/* Fetch all orphaned 'RW' packets and send credit update. */
>+	bytes_dropped = virtio_transport_drop_until_seq_begin(vvs);
>+
>+	if (list_empty(&vvs->rx_queue))
>+		goto out;

What do we return to in this case?

IIUC we return the len of the previous packet, should we set 
vvs->seqpacket_state.user_read_seq_len to 0?

>+
>+	pkt = list_first_entry(&vvs->rx_queue, struct virtio_vsock_pkt, list);
>+
>+	vvs->seqpacket_state.user_read_copied = 0;
>+
>+	seq_hdr = (struct virtio_vsock_seq_hdr *)pkt->buf;
>+	vvs->seqpacket_state.user_read_seq_len = 
>le32_to_cpu(seq_hdr->msg_len);
>+	vvs->seqpacket_state.curr_rx_msg_id = le32_to_cpu(seq_hdr->msg_id);
>+	virtio_transport_dec_rx_pkt(vvs, pkt);
>+	virtio_transport_remove_pkt(pkt);
>+out:
>+	spin_unlock_bh(&vvs->rx_lock);
>+
>+	if (bytes_dropped)
>+		virtio_transport_send_credit_update(vsk);
>+
>+	return vvs->seqpacket_state.user_read_seq_len;
>+}
>+EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_seq_get_len);
>+
> static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
> 						 struct msghdr *msg,
> 						 bool *msg_ready)
>-- 
>2.25.1
>

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Re: [RFC PATCH v6 07/22] af_vsock: rest of SEQPACKET support

[Stefano Garzarella]

On Sun, Mar 07, 2021 at 09:00:47PM +0300, Arseny Krasnov wrote:
>This does rest of SOCK_SEQPACKET support:
>1) Adds socket ops for SEQPACKET type.
>2) Allows to create socket with SEQPACKET type.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> include/net/af_vsock.h   |  1 +
> net/vmw_vsock/af_vsock.c | 36 +++++++++++++++++++++++++++++++++++-
> 2 files changed, 36 insertions(+), 1 deletion(-)

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

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Re: [RFC PATCH v6 08/22] af_vsock: update comments for stream sockets

[Stefano Garzarella]

On Sun, Mar 07, 2021 at 09:01:05PM +0300, Arseny Krasnov wrote:
>This replaces 'stream' to 'connection oriented' in comments as
>SEQPACKET is also connection oriented.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> net/vmw_vsock/af_vsock.c | 31 +++++++++++++++++--------------
> 1 file changed, 17 insertions(+), 14 deletions(-)

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

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Re: [RFC PATCH v6 09/22] virtio/vsock: set packet's type in virtio_transport_send_pkt_info()

[Stefano Garzarella]

On Sun, Mar 07, 2021 at 09:01:22PM +0300, Arseny Krasnov wrote:
>This moves passing type of packet from 'info' structure to  'virtio_
>transport_send_pkt_info()' function. There is no need to set type of
>packet which differs from type of socket. Since at current time only
>stream type is supported, set it directly in 'virtio_transport_send_
>pkt_info()', so callers don't need to set it.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> net/vmw_vsock/virtio_transport_common.c | 19 +++++--------------
> 1 file changed, 5 insertions(+), 14 deletions(-)

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

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Re: [RFC PATCH v6 10/22] virtio/vsock: simplify credit update function API

[Stefano Garzarella]

On Sun, Mar 07, 2021 at 09:01:44PM +0300, Arseny Krasnov wrote:
>This function is static and 'hdr' arg was always NULL.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> net/vmw_vsock/virtio_transport_common.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

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Re: [RFC PATCH v6 11/22] virtio/vsock: dequeue callback for SOCK_SEQPACKET

[Stefano Garzarella]

On Sun, Mar 07, 2021 at 09:02:01PM +0300, Arseny Krasnov wrote:
>This adds transport callback and it's logic for SEQPACKET dequeue.
>Callback fetches RW packets from rx queue of socket until whole record
>is copied(if user's buffer is full, user is not woken up). This is done
>to not stall sender, because if we wake up user and it leaves syscall,
>nobody will send credit update for rest of record, and sender will wait
>for next enter of read syscall at receiver's side. So if user buffer is
>full, we just send credit update and drop data. If during copy SEQ_BEGIN
>was found(and not all data was copied), copying is restarted by reset
>user's iov iterator(previous unfinished data is dropped).
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> include/linux/virtio_vsock.h            |  13 +++
> include/uapi/linux/virtio_vsock.h       |  16 ++++
> net/vmw_vsock/virtio_transport_common.c | 116 ++++++++++++++++++++++++
> 3 files changed, 145 insertions(+)
>
>diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>index dc636b727179..466a5832d2f5 100644
>--- a/include/linux/virtio_vsock.h
>+++ b/include/linux/virtio_vsock.h
>@@ -18,6 +18,12 @@ enum {
> 	VSOCK_VQ_MAX    = 3,
> };
>
>+struct virtio_vsock_seqpack_state {
>+	u32 user_read_seq_len;
>+	u32 user_read_copied;
>+	u32 curr_rx_msg_id;
>+};
>+
> /* Per-socket state (accessed via vsk->trans) */
> struct virtio_vsock_sock {
> 	struct vsock_sock *vsk;
>@@ -36,6 +42,8 @@ struct virtio_vsock_sock {
> 	u32 rx_bytes;
> 	u32 buf_alloc;
> 	struct list_head rx_queue;
>+
>+	struct virtio_vsock_seqpack_state seqpacket_state;

Following 'virtio_vsock_seq_hdr', maybe we can shorten in:

         struct virtio_vsock_seq_state seq_state;

The rest LGTM.

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Re: [RFC PATCH v6 13/22] virtio/vsock: add SEQPACKET receive logic

[Stefano Garzarella]

On Sun, Mar 07, 2021 at 09:02:50PM +0300, Arseny Krasnov wrote:
>This modifies current receive logic for SEQPACKET support:
>1) Inserts 'SEQ_BEGIN' packet to socket's rx queue.
>2) Inserts 'RW' packet to socket's rx queue, but without merging with
>   buffer of last packet in queue.
>3) Performs check for packet and socket types on receive(if mismatch,
>   then reset connection).
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> net/vmw_vsock/virtio_transport_common.c | 63 +++++++++++++++++--------
> 1 file changed, 44 insertions(+), 19 deletions(-)
>
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index 6fc78fec41c0..9d86375935ce 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -165,6 +165,14 @@ void virtio_transport_deliver_tap_pkt(struct virtio_vsock_pkt *pkt)
> }
> EXPORT_SYMBOL_GPL(virtio_transport_deliver_tap_pkt);
>
>+static u16 virtio_transport_get_type(struct sock *sk)
>+{
>+	if (sk->sk_type == SOCK_STREAM)
>+		return VIRTIO_VSOCK_TYPE_STREAM;
>+	else
>+		return VIRTIO_VSOCK_TYPE_SEQPACKET;
>+}
>+
> /* This function can only be used on connecting/connected sockets,
>  * since a socket assigned to a transport is required.
>  *
>@@ -1062,25 +1070,27 @@ virtio_transport_recv_enqueue(struct vsock_sock *vsk,
> 		goto out;
> 	}
>
>-	/* Try to copy small packets into the buffer of last packet queued,
>-	 * to avoid wasting memory queueing the entire buffer with a small
>-	 * payload.
>-	 */
>-	if (pkt->len <= GOOD_COPY_LEN && !list_empty(&vvs->rx_queue)) {
>-		struct virtio_vsock_pkt *last_pkt;
>+	if (le16_to_cpu(pkt->hdr.type) == VIRTIO_VSOCK_TYPE_STREAM) {
>+		/* Try to copy small packets into the buffer of last packet queued,
>+		 * to avoid wasting memory queueing the entire buffer with a small
>+		 * payload.
>+		 */
>+		if (pkt->len <= GOOD_COPY_LEN && !list_empty(&vvs->rx_queue)) {
>+			struct virtio_vsock_pkt *last_pkt;
>
>-		last_pkt = list_last_entry(&vvs->rx_queue,
>-					   struct virtio_vsock_pkt, list);
>+			last_pkt = list_last_entry(&vvs->rx_queue,
>+						   struct virtio_vsock_pkt, list);
>
>-		/* If there is space in the last packet queued, we copy the
>-		 * new packet in its buffer.
>-		 */
>-		if (pkt->len <= last_pkt->buf_len - last_pkt->len) {
>-			memcpy(last_pkt->buf + last_pkt->len, pkt->buf,
>-			       pkt->len);
>-			last_pkt->len += pkt->len;
>-			free_pkt = true;
>-			goto out;
>+			/* If there is space in the last packet queued, we copy the
>+			 * new packet in its buffer.
>+			 */
>+			if (pkt->len <= last_pkt->buf_len - last_pkt->len) {
>+				memcpy(last_pkt->buf + last_pkt->len, pkt->buf,
>+				       pkt->len);
>+				last_pkt->len += pkt->len;
>+				free_pkt = true;
>+				goto out;
>+			}
> 		}
> 	}
>
>@@ -1100,9 +1110,13 @@ virtio_transport_recv_connected(struct sock *sk,
> 	int err = 0;
>
> 	switch (le16_to_cpu(pkt->hdr.op)) {
>+	case VIRTIO_VSOCK_OP_SEQ_BEGIN:
>+	case VIRTIO_VSOCK_OP_SEQ_END:
> 	case VIRTIO_VSOCK_OP_RW:
> 		virtio_transport_recv_enqueue(vsk, pkt);
>-		sk->sk_data_ready(sk);
>+
>+		if (le16_to_cpu(pkt->hdr.op) != VIRTIO_VSOCK_OP_SEQ_BEGIN)
>+			sk->sk_data_ready(sk);
> 		return err;
> 	case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
> 		sk->sk_write_space(sk);
>@@ -1245,6 +1259,12 @@ virtio_transport_recv_listen(struct sock *sk, struct virtio_vsock_pkt *pkt,
> 	return 0;
> }
>
>+static bool virtio_transport_valid_type(u16 type)
>+{
>+	return (type == VIRTIO_VSOCK_TYPE_STREAM) ||
>+	       (type == VIRTIO_VSOCK_TYPE_SEQPACKET);
>+}
>+
> /* We are under the virtio-vsock's vsock->rx_lock or vhost-vsock's vq->mutex
>  * lock.
>  */
>@@ -1270,7 +1290,7 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
> 					le32_to_cpu(pkt->hdr.buf_alloc),
> 					le32_to_cpu(pkt->hdr.fwd_cnt));
>
>-	if (le16_to_cpu(pkt->hdr.type) != VIRTIO_VSOCK_TYPE_STREAM) {
>+	if (!virtio_transport_valid_type(le16_to_cpu(pkt->hdr.type))) {
> 		(void)virtio_transport_reset_no_sock(t, pkt);
> 		goto free_pkt;
> 	}
>@@ -1287,6 +1307,11 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
> 		}
> 	}
>
>+	if (virtio_transport_get_type(sk) != le16_to_cpu(pkt->hdr.type)) {
>+		(void)virtio_transport_reset_no_sock(t, pkt);

We must release the refcnt acquired by vsock_find_connected_socket() or 
vsock_find_bound_socket(), so we need to add:

                 sock_put(sk);


>+		goto free_pkt;
>+	}
>+
> 	vsk = vsock_sk(sk);
>
> 	lock_sock(sk);
>-- 
>2.25.1
>

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Re: [RFC PATCH v6 14/22] virtio/vsock: rest of SOCK_SEQPACKET support

[Stefano Garzarella]

On Sun, Mar 07, 2021 at 09:03:09PM +0300, Arseny Krasnov wrote:
>This adds rest of logic for SEQPACKET:
>1) SEQPACKET specific functions which send SEQ_BEGIN/SEQ_END.
>   Note that both functions may sleep to wait enough space for
>   SEQPACKET header.
>2) SEQ_BEGIN/SEQ_END in TAP packet capture.
>3) Send SHUTDOWN on socket close for SEQPACKET type.
>4) Set SEQPACKET packet type during send.
>5) Set MSG_EOR in flags for SEQPACKET during send.
>6) 'seqpacket_allow' flag to virtio transport.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> include/linux/virtio_vsock.h            |  8 +++
> net/vmw_vsock/virtio_transport_common.c | 87 ++++++++++++++++++++++++-
> 2 files changed, 93 insertions(+), 2 deletions(-)
>
>diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>index d7edcfeb4cd2..6b45a8b98226 100644
>--- a/include/linux/virtio_vsock.h
>+++ b/include/linux/virtio_vsock.h
>@@ -22,6 +22,7 @@ struct virtio_vsock_seqpack_state {
> 	u32 user_read_seq_len;
> 	u32 user_read_copied;
> 	u32 curr_rx_msg_id;
>+	u32 next_tx_msg_id;
> };
>
> /* Per-socket state (accessed via vsk->trans) */
>@@ -76,6 +77,8 @@ struct virtio_transport {
>
> 	/* Takes ownership of the packet */
> 	int (*send_pkt)(struct virtio_vsock_pkt *pkt);
>+
>+	bool seqpacket_allow;
> };
>
> ssize_t
>@@ -90,6 +93,11 @@ virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
>
> size_t virtio_transport_seqpacket_seq_get_len(struct vsock_sock *vsk);
> int
>+virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,
>+				   struct msghdr *msg,
>+				   int flags,
>+				   size_t len);
>+int
> virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
> 				   struct msghdr *msg,
> 				   int flags,
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index 9d86375935ce..8e9fdd8aba5d 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -139,6 +139,8 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
> 		break;
> 	case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
> 	case VIRTIO_VSOCK_OP_CREDIT_REQUEST:
>+	case VIRTIO_VSOCK_OP_SEQ_BEGIN:
>+	case VIRTIO_VSOCK_OP_SEQ_END:
> 		hdr->op = cpu_to_le16(AF_VSOCK_OP_CONTROL);
> 		break;
> 	default:
>@@ -187,7 +189,12 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
> 	struct virtio_vsock_pkt *pkt;
> 	u32 pkt_len = info->pkt_len;
>
>-	info->type = VIRTIO_VSOCK_TYPE_STREAM;
>+	info->type = virtio_transport_get_type(sk_vsock(vsk));
>+
>+	if (info->type == VIRTIO_VSOCK_TYPE_SEQPACKET &&
>+	    info->msg &&
>+	    info->msg->msg_flags & MSG_EOR)
>+		info->flags |= VIRTIO_VSOCK_RW_EOR;
>
> 	t_ops = virtio_transport_get_ops(vsk);
> 	if (unlikely(!t_ops))
>@@ -401,6 +408,43 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
> 	return err;
> }
>
>+static int virtio_transport_seqpacket_send_ctrl(struct vsock_sock *vsk,
>+						int type,
>+						size_t len,
>+						int flags)
>+{
>+	struct virtio_vsock_sock *vvs = vsk->trans;
>+	struct virtio_vsock_pkt_info info = {
>+		.op = type,
>+		.vsk = vsk,
>+		.pkt_len = sizeof(struct virtio_vsock_seq_hdr)
>+	};
>+
>+	struct virtio_vsock_seq_hdr seq_hdr = {
>+		.msg_id = cpu_to_le32(vvs->seqpacket_state.next_tx_msg_id),
>+		.msg_len = cpu_to_le32(len)
>+	};
>+
>+	struct kvec seq_hdr_kiov = {
>+		.iov_base = (void *)&seq_hdr,
>+		.iov_len = sizeof(struct virtio_vsock_seq_hdr)
>+	};
>+
>+	struct msghdr msg = {0};
>+
>+	//XXX: do we need 'vsock_transport_send_notify_data' pointer?
>+	if (vsock_wait_space(sk_vsock(vsk),
>+			     sizeof(struct virtio_vsock_seq_hdr),
>+			     flags, NULL))
>+		return -1;
>+
>+	iov_iter_kvec(&msg.msg_iter, WRITE, &seq_hdr_kiov, 1, sizeof(seq_hdr));
>+
>+	info.msg = &msg;
>+
>+	return virtio_transport_send_pkt_info(vsk, &info);
>+}
>+
> static inline void virtio_transport_remove_pkt(struct virtio_vsock_pkt *pkt)
> {
> 	list_del(&pkt->list);
>@@ -582,6 +626,45 @@ virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
> }
> EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);
>
>+int
>+virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,
>+				   struct msghdr *msg,
>+				   int flags,
>+				   size_t len)
>+{
>+	int written;
>+
>+	if (msg->msg_iter.iov_offset == 0) {
>+		/* Send SEQBEGIN. */
>+		if (virtio_transport_seqpacket_send_ctrl(vsk,
>+							 VIRTIO_VSOCK_OP_SEQ_BEGIN,
>+							 len,
>+							 flags) < 0)
>+			return -1;
>+	}
>+
>+	written = virtio_transport_stream_enqueue(vsk, msg, len);
>+
>+	if (written < 0)
>+		return -1;
>+
>+	if (msg->msg_iter.count == 0) {
>+		struct virtio_vsock_sock *vvs = vsk->trans;
>+
>+		/* Send SEQEND. */
>+		if (virtio_transport_seqpacket_send_ctrl(vsk,
>+							 VIRTIO_VSOCK_OP_SEQ_END,
>+							 0,
>+							 flags) < 0)
>+			return -1;
>+
>+		vvs->seqpacket_state.next_tx_msg_id++;
>+	}

I suspect we should increment next_tx_msg_id even in case of an error to 
avoid issues with packets with same IDs, so in case of error I would do:

	if (/* error */) {
		written = -1;
		goto out;
	}

Then we can add the 'out' label and the id increment:

out:
	vvs->seqpacket_state.next_tx_msg_id++;
>+
>+	return written;
>+}
>+EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_enqueue);
>+
> int
> virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
> 			       struct msghdr *msg,
>@@ -1001,7 +1084,7 @@ void virtio_transport_release(struct vsock_sock *vsk)
> 	struct sock *sk = &vsk->sk;
> 	bool remove_sock = true;
>
>-	if (sk->sk_type == SOCK_STREAM)
>+	if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)
> 		remove_sock = virtio_transport_close(vsk);
>
> 	list_for_each_entry_safe(pkt, tmp, &vvs->rx_queue, list) {
>-- 
>2.25.1
>

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Re: [RFC PATCH v6 16/22] vhost/vsock: SEQPACKET feature bit support

[Stefano Garzarella]

On Sun, Mar 07, 2021 at 09:03:41PM +0300, Arseny Krasnov wrote:
>This adds handling of SEQPACKET bit: if guest sets features with
>this bit cleared, then SOCK_SEQPACKET support will be disabled.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> drivers/vhost/vsock.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)

I think is better to move this patch after we set the seqpackets ops,
so we are really able to handle SEQPACKET traffic.

>
>diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
>index 5e78fb719602..3b0a50e6de12 100644
>--- a/drivers/vhost/vsock.c
>+++ b/drivers/vhost/vsock.c
>@@ -31,7 +31,8 @@
>
> enum {
> 	VHOST_VSOCK_FEATURES = VHOST_FEATURES |
>-			       (1ULL << VIRTIO_F_ACCESS_PLATFORM)
>+			       (1ULL << VIRTIO_F_ACCESS_PLATFORM) |
>+			       (1ULL << VIRTIO_VSOCK_F_SEQPACKET)
> };
>
> enum {
>@@ -785,6 +786,9 @@ static int vhost_vsock_set_features(struct vhost_vsock *vsock, u64 features)
> 			goto err;
> 	}
>
>+	if (features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET))
>+		vhost_transport.seqpacket_allow = true;
>+
> 	for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
> 		vq = &vsock->vqs[i];
> 		mutex_lock(&vq->mutex);
>-- 
>2.25.1
>

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Re: [RFC PATCH v6 17/22] virtio/vsock: SEQPACKET feature bit support

[Stefano Garzarella]

On Sun, Mar 07, 2021 at 09:04:01PM +0300, Arseny Krasnov wrote:
>This adds handling of SEQPACKET bit: guest tries to negotiate it
>with vhost.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> net/vmw_vsock/virtio_transport.c | 5 +++++
> 1 file changed, 5 insertions(+)

Also for this patch I think is better to move after we set the 
seqpackets ops.

>
>diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
>index 2700a63ab095..41c5d0a31e08 100644
>--- a/net/vmw_vsock/virtio_transport.c
>+++ b/net/vmw_vsock/virtio_transport.c
>@@ -612,6 +612,10 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
> 	rcu_assign_pointer(the_virtio_vsock, vsock);
>
> 	mutex_unlock(&the_virtio_vsock_mutex);
>+
>+	if (vdev->features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET))
>+		virtio_transport.seqpacket_allow = true;
>+
> 	return 0;
>
> out:
>@@ -695,6 +699,7 @@ static struct virtio_device_id id_table[] = {
> };
>
> static unsigned int features[] = {
>+	VIRTIO_VSOCK_F_SEQPACKET
> };
>
> static struct virtio_driver virtio_vsock_driver = {
>-- 
>2.25.1
>

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Re: [RFC PATCH v6 00/22] virtio/vsock: introduce SOCK_SEQPACKET support

[Stefano Garzarella]

Hi Arseny,

On Sun, Mar 07, 2021 at 08:57:19PM +0300, Arseny Krasnov wrote:
>	This patchset implements support of SOCK_SEQPACKET for virtio
>transport.
>	As SOCK_SEQPACKET guarantees to save record boundaries, so to
>do it, two new packet operations were added: first for start of record
> and second to mark end of record(SEQ_BEGIN and SEQ_END later). Also,
>both operations carries metadata - to maintain boundaries and payload
>integrity. Metadata is introduced by adding special header with two
>fields - message id and message length:
>
>	struct virtio_vsock_seq_hdr {
>		__le32  msg_id;
>		__le32  msg_len;
>	} __attribute__((packed));
>
>	This header is transmitted as payload of SEQ_BEGIN and SEQ_END
>packets(buffer of second virtio descriptor in chain) in the same way as
>data transmitted in RW packets. Payload was chosen as buffer for this
>header to avoid touching first virtio buffer which carries header of
>packet, because someone could check that size of this buffer is equal
>to size of packet header. To send record, packet with start marker is
>sent first(it's header carries length of record and id),then all data
>is sent as usual 'RW' packets and finally SEQ_END is sent(it carries
>id of message, which is equal to id of SEQ_BEGIN), also after sending
>SEQ_END id is incremented. On receiver's side,size of record is known
>from packet with start record marker. To check that no packets were
>dropped by transport, 'msg_id's of two sequential SEQ_BEGIN and SEQ_END
>are checked to be equal and length of data between two markers is
>compared to then length in SEQ_BEGIN header.
>	Now as  packets of one socket are not reordered neither on
>vsock nor on vhost transport layers, such markers allows to restore
>original record on receiver's side. If user's buffer is smaller that
>record length, when all out of size data is dropped.
>	Maximum length of datagram is not limited as in stream socket,
>because same credit logic is used. Difference with stream socket is
>that user is not woken up until whole record is received or error
>occurred. Implementation also supports 'MSG_EOR' and 'MSG_TRUNC' flags.
>	Tests also implemented.
>
>	Thanks to stsp2@yandex.ru for encouragements and initial design
>recommendations.
>
> Arseny Krasnov (22):
>  af_vsock: update functions for connectible socket
>  af_vsock: separate wait data loop
>  af_vsock: separate receive data loop
>  af_vsock: implement SEQPACKET receive loop
>  af_vsock: separate wait space loop
>  af_vsock: implement send logic for SEQPACKET
>  af_vsock: rest of SEQPACKET support
>  af_vsock: update comments for stream sockets
>  virtio/vsock: set packet's type in virtio_transport_send_pkt_info()
>  virtio/vsock: simplify credit update function API
>  virtio/vsock: dequeue callback for SOCK_SEQPACKET
>  virtio/vsock: fetch length for SEQPACKET record
>  virtio/vsock: add SEQPACKET receive logic
>  virtio/vsock: rest of SOCK_SEQPACKET support
>  virtio/vsock: SEQPACKET feature bit
>  vhost/vsock: SEQPACKET feature bit support
>  virtio/vsock: SEQPACKET feature bit support
>  virtio/vsock: setup SEQPACKET ops for transport
>  vhost/vsock: setup SEQPACKET ops for transport
>  vsock/loopback: setup SEQPACKET ops for transport
>  vsock_test: add SOCK_SEQPACKET tests
>  virtio/vsock: update trace event for SEQPACKET
>
> drivers/vhost/vsock.c                        |  22 +-
> include/linux/virtio_vsock.h                 |  22 +
> include/net/af_vsock.h                       |  10 +
> .../events/vsock_virtio_transport_common.h   |  48 +-
> include/uapi/linux/virtio_vsock.h            |  19 +
> net/vmw_vsock/af_vsock.c                     | 589 +++++++++++------
> net/vmw_vsock/virtio_transport.c             |  18 +
> net/vmw_vsock/virtio_transport_common.c      | 364 ++++++++--
> net/vmw_vsock/vsock_loopback.c               |  13 +
> tools/testing/vsock/util.c                   |  32 +-
> tools/testing/vsock/util.h                   |   3 +
> tools/testing/vsock/vsock_test.c             | 126 ++++
> 12 files changed, 1013 insertions(+), 253 deletions(-)
>
> v5 -> v6:
> General changelog:
> - virtio transport specific callbacks which send SEQ_BEGIN or
>   SEQ_END now hidden inside virtio transport. Only enqueue,
>   dequeue and record length callbacks are provided by transport.
>
> - virtio feature bit for SEQPACKET socket support introduced:
>   VIRTIO_VSOCK_F_SEQPACKET.
>
> - 'msg_cnt' field in 'struct virtio_vsock_seq_hdr' renamed to
>   'msg_id' and used as id.
>
> Per patch changelog:
> - 'af_vsock: separate wait data loop':
>    1) Commit message updated.
>    2) 'prepare_to_wait()' moved inside while loop(thanks to
>      Jorgen Hansen).
>    Marked 'Reviewed-by' with 1), but as 2) I removed R-b.
>
> - 'af_vsock: separate receive data loop': commit message
>    updated.
>    Marked 'Reviewed-by' with that fix.
>
> - 'af_vsock: implement SEQPACKET receive loop': style fixes.
>
> - 'af_vsock: rest of SEQPACKET support':
>    1) 'module_put()' added when transport callback check failed.
>    2) Now only 'seqpacket_allow()' callback called to check
>       support of SEQPACKET by transport.
>
> - 'af_vsock: update comments for stream sockets': commit message
>    updated.
>    Marked 'Reviewed-by' with that fix.
>
> - 'virtio/vsock: set packet's type in send':
>    1) Commit message updated.
>    2) Parameter 'type' from 'virtio_transport_send_credit_update()'
>       also removed in this patch instead of in next.
>
> - 'virtio/vsock: dequeue callback for SOCK_SEQPACKET': SEQPACKET
>    related state wrapped to special struct.
>
> - 'virtio/vsock: update trace event for SEQPACKET': format strings
>    now not broken by new lines.

I left a bunch of comments in the patches, I hope they are easy to fix 
:-)

Thanks for the changelogs. About 'per patch changelog', it is very 
useful!
Just a suggestion, I think is better to include them in each patch after 
the '---' to simplify the review.

You can use git-notes(1) or you can simply edit the format-patch and add 
the changelog after the 3 dashes, so that they are ignored when the 
patch is applied.

Thanks,
Stefano

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Re: [RFC PATCH v6 00/22] virtio/vsock: introduce SOCK_SEQPACKET support

[Stefano Garzarella]

On Tue, Mar 16, 2021 at 06:37:31AM +0300, Arseny Krasnov wrote:
>
>On 15.03.2021 18:22, Arseny Krasnov wrote:
>> On 15.03.2021 14:40, Stefano Garzarella wrote:
>>> Hi Arseny,
>>>
>>> On Sun, Mar 07, 2021 at 08:57:19PM +0300, Arseny Krasnov wrote:
>>>> 	This patchset implements support of SOCK_SEQPACKET for virtio
>>>> transport.
>>>> 	As SOCK_SEQPACKET guarantees to save record boundaries, so to
>>>> do it, two new packet operations were added: first for start of record
>>>> and second to mark end of record(SEQ_BEGIN and SEQ_END later). Also,
>>>> both operations carries metadata - to maintain boundaries and payload
>>>> integrity. Metadata is introduced by adding special header with two
>>>> fields - message id and message length:
>>>>
>>>> 	struct virtio_vsock_seq_hdr {
>>>> 		__le32  msg_id;
>>>> 		__le32  msg_len;
>>>> 	} __attribute__((packed));
>>>>
>>>> 	This header is transmitted as payload of SEQ_BEGIN and SEQ_END
>>>> packets(buffer of second virtio descriptor in chain) in the same way as
>>>> data transmitted in RW packets. Payload was chosen as buffer for this
>>>> header to avoid touching first virtio buffer which carries header of
>>>> packet, because someone could check that size of this buffer is equal
>>>> to size of packet header. To send record, packet with start marker is
>>>> sent first(it's header carries length of record and id),then all data
>>>> is sent as usual 'RW' packets and finally SEQ_END is sent(it carries
>>>> id of message, which is equal to id of SEQ_BEGIN), also after sending
>>>> SEQ_END id is incremented. On receiver's side,size of record is known
>>> >from packet with start record marker. To check that no packets were
>>>> dropped by transport, 'msg_id's of two sequential SEQ_BEGIN and SEQ_END
>>>> are checked to be equal and length of data between two markers is
>>>> compared to then length in SEQ_BEGIN header.
>>>> 	Now as  packets of one socket are not reordered neither on
>>>> vsock nor on vhost transport layers, such markers allows to restore
>>>> original record on receiver's side. If user's buffer is smaller that
>>>> record length, when all out of size data is dropped.
>>>> 	Maximum length of datagram is not limited as in stream socket,
>>>> because same credit logic is used. Difference with stream socket is
>>>> that user is not woken up until whole record is received or error
>>>> occurred. Implementation also supports 'MSG_EOR' and 'MSG_TRUNC' flags.
>>>> 	Tests also implemented.
>>>>
>>>> 	Thanks to stsp2@yandex.ru for encouragements and initial design
>>>> recommendations.
>>>>
>>>> Arseny Krasnov (22):
>>>>  af_vsock: update functions for connectible socket
>>>>  af_vsock: separate wait data loop
>>>>  af_vsock: separate receive data loop
>>>>  af_vsock: implement SEQPACKET receive loop
>>>>  af_vsock: separate wait space loop
>>>>  af_vsock: implement send logic for SEQPACKET
>>>>  af_vsock: rest of SEQPACKET support
>>>>  af_vsock: update comments for stream sockets
>>>>  virtio/vsock: set packet's type in virtio_transport_send_pkt_info()
>>>>  virtio/vsock: simplify credit update function API
>>>>  virtio/vsock: dequeue callback for SOCK_SEQPACKET
>>>>  virtio/vsock: fetch length for SEQPACKET record
>>>>  virtio/vsock: add SEQPACKET receive logic
>>>>  virtio/vsock: rest of SOCK_SEQPACKET support
>>>>  virtio/vsock: SEQPACKET feature bit
>>>>  vhost/vsock: SEQPACKET feature bit support
>>>>  virtio/vsock: SEQPACKET feature bit support
>>>>  virtio/vsock: setup SEQPACKET ops for transport
>>>>  vhost/vsock: setup SEQPACKET ops for transport
>>>>  vsock/loopback: setup SEQPACKET ops for transport
>>>>  vsock_test: add SOCK_SEQPACKET tests
>>>>  virtio/vsock: update trace event for SEQPACKET
>>>>
>>>> drivers/vhost/vsock.c                        |  22 +-
>>>> include/linux/virtio_vsock.h                 |  22 +
>>>> include/net/af_vsock.h                       |  10 +
>>>> .../events/vsock_virtio_transport_common.h   |  48 +-
>>>> include/uapi/linux/virtio_vsock.h            |  19 +
>>>> net/vmw_vsock/af_vsock.c                     | 589 +++++++++++------
>>>> net/vmw_vsock/virtio_transport.c             |  18 +
>>>> net/vmw_vsock/virtio_transport_common.c      | 364 ++++++++--
>>>> net/vmw_vsock/vsock_loopback.c               |  13 +
>>>> tools/testing/vsock/util.c                   |  32 +-
>>>> tools/testing/vsock/util.h                   |   3 +
>>>> tools/testing/vsock/vsock_test.c             | 126 ++++
>>>> 12 files changed, 1013 insertions(+), 253 deletions(-)
>>>>
>>>> v5 -> v6:
>>>> General changelog:
>>>> - virtio transport specific callbacks which send SEQ_BEGIN or
>>>>   SEQ_END now hidden inside virtio transport. Only enqueue,
>>>>   dequeue and record length callbacks are provided by transport.
>>>>
>>>> - virtio feature bit for SEQPACKET socket support introduced:
>>>>   VIRTIO_VSOCK_F_SEQPACKET.
>>>>
>>>> - 'msg_cnt' field in 'struct virtio_vsock_seq_hdr' renamed to
>>>>   'msg_id' and used as id.
>>>>
>>>> Per patch changelog:
>>>> - 'af_vsock: separate wait data loop':
>>>>    1) Commit message updated.
>>>>    2) 'prepare_to_wait()' moved inside while loop(thanks to
>>>>      Jorgen Hansen).
>>>>    Marked 'Reviewed-by' with 1), but as 2) I removed R-b.
>>>>
>>>> - 'af_vsock: separate receive data loop': commit message
>>>>    updated.
>>>>    Marked 'Reviewed-by' with that fix.
>>>>
>>>> - 'af_vsock: implement SEQPACKET receive loop': style fixes.
>>>>
>>>> - 'af_vsock: rest of SEQPACKET support':
>>>>    1) 'module_put()' added when transport callback check failed.
>>>>    2) Now only 'seqpacket_allow()' callback called to check
>>>>       support of SEQPACKET by transport.
>>>>
>>>> - 'af_vsock: update comments for stream sockets': commit message
>>>>    updated.
>>>>    Marked 'Reviewed-by' with that fix.
>>>>
>>>> - 'virtio/vsock: set packet's type in send':
>>>>    1) Commit message updated.
>>>>    2) Parameter 'type' from 'virtio_transport_send_credit_update()'
>>>>       also removed in this patch instead of in next.
>>>>
>>>> - 'virtio/vsock: dequeue callback for SOCK_SEQPACKET': SEQPACKET
>>>>    related state wrapped to special struct.
>>>>
>>>> - 'virtio/vsock: update trace event for SEQPACKET': format strings
>>>>    now not broken by new lines.
>>> I left a bunch of comments in the patches, I hope they are easy to fix
>>> :-)
>> Thank you, yes, there are still small fixes.
>
>So one more question, this is final review for this version of patchset and can
>
>prepare next version with fixes? All other patches will reviewed in next version?
>

For me yes, the other patches seem okay, but I would like to see them 
later, with the right order and the last things fixed.

Maybe to merge all this we should wait for the agreement from the specs 
patch.

Thanks,
Stefano

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