[RFC PATCH v8 15/19] vhost/vsock: enable SEQPACKET for transport

Arseny Krasnov
2021-04-13T12:47:47Z

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 <arseny.krasnov@kaspersky.com>
---
v7 -> v8:
- This patch merged with patch which adds SEQPACKET feature bit to
virtio transport.
- It now handles VIRTIO_VSOCK_SEQ_EOR bit(see commit msg).

drivers/vhost/vsock.c | 31 ++++++++++++++++++++++++++++---
1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 5e78fb719602..0969cdc87830 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 {
@@ -112,6 +113,7 @@ 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 +176,12 @@ 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 &&
+ pkt->hdr.flags & VIRTIO_VSOCK_SEQ_EOR) {
+ pkt->hdr.flags &= ~VIRTIO_VSOCK_SEQ_EOR;
+ restore_flag = true;
+ }
+
nbytes = copy_to_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter);
if (nbytes != sizeof(pkt->hdr)) {
virtio_transport_free_pkt(pkt);
@@ -181,6 +189,9 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
break;
}

+ if (restore_flag)
+ pkt->hdr.flags |= VIRTIO_VSOCK_SEQ_EOR;
+
nbytes = copy_to_iter(pkt->buf + pkt->off, payload_len,
&iov_iter);
if (nbytes != payload_len) {
@@ -354,8 +365,7 @@ vhost_vsock_alloc_pkt(struct vhost_virtqueue *vq,
return NULL;
}

- if (le16_to_cpu(pkt->hdr.type) == VIRTIO_VSOCK_TYPE_STREAM)
- pkt->len = le32_to_cpu(pkt->hdr.len);
+ pkt->len = le32_to_cpu(pkt->hdr.len);

/* No payload */
if (!pkt->len)
@@ -398,6 +408,8 @@ static bool vhost_vsock_more_replies(struct vhost_vsock *vsock)
return val < vq->num;
}

+static bool vhost_transport_seqpacket_allow(void);
+
static struct virtio_transport vhost_transport = {
.transport = {
.module = THIS_MODULE,
@@ -424,6 +436,10 @@ static struct virtio_transport vhost_transport = {
.stream_is_active = virtio_transport_stream_is_active,
.stream_allow = virtio_transport_stream_allow,

+ .seqpacket_dequeue = virtio_transport_seqpacket_dequeue,
+ .seqpacket_enqueue = virtio_transport_seqpacket_enqueue,
+ .seqpacket_allow = vhost_transport_seqpacket_allow,
+
.notify_poll_in = virtio_transport_notify_poll_in,
.notify_poll_out = virtio_transport_notify_poll_out,
.notify_recv_init = virtio_transport_notify_recv_init,
@@ -439,8 +455,14 @@ static struct virtio_transport vhost_transport = {
},

.send_pkt = vhost_transport_send_pkt,
+ .seqpacket_allow = false
};

+static bool vhost_transport_seqpacket_allow(void)
+{
+ return vhost_transport.seqpacket_allow;
+}
+
static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
{
struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
@@ -785,6 +807,9 @@ 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