This removes:
1) Ignore of non-stream type of packets.
This adds:
1) Handling of SEQPACKET bit: if guest sets features with this bit cleared,
  then SOCK_SEQPACKET support will be disabled.
2) 'seqpacket_allow()' callback.
3) Handling of SEQ_EOR bit: when vhost places data in buffers of guest's
  rx queue, keep this bit set only when last piece of data is copied.

Signed-off-by: Arseny Krasnov <redacted>
---
v8 -> v9:
1) Move 'seqpacket_allow' to 'struct vhost_vsock'.
2) Use cpu_to_le32()/le32_to_cpu() to work with 'flags' of packet.

drivers/vhost/vsock.c | 42 +++++++++++++++++++++++++++++++++++++++---
1 file changed, 39 insertions(+), 3 deletions(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 5e78fb719602..3395b25d4a35 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 {

@@ -56,6 +57,7 @@ struct vhost_vsock {

	atomic_t queued_replies;

	u32 guest_cid;
+	bool seqpacket_allow;
};

static u32 vhost_transport_get_local_cid(void)

@@ -112,6 +114,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,

		size_t nbytes;
		size_t iov_len, payload_len;
		int head;
+		bool restore_flag = false;

		spin_lock_bh(&vsock->send_pkt_list_lock);
		if (list_empty(&vsock->send_pkt_list)) {

@@ -174,6 +177,12 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,

		/* Set the correct length in the header */
		pkt->hdr.len = cpu_to_le32(payload_len);

+		if (pkt->off + payload_len < pkt->len &&
+		    le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOR) {
+			pkt->hdr.flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
+			restore_flag = true;
+		}