linux-toradex.git/drivers/vhost/vsock.c, branch v6.17

vsock/virtio: Rename virtio_vsock_skb_rx_put()

2025-08-01T13:11:09+00:00

In preparation for using virtio_vsock_skb_rx_put() when populating SKBs
on the vsock TX path, rename virtio_vsock_skb_rx_put() to
virtio_vsock_skb_put().

No functional change.

Reviewed-by: Stefano Garzarella 
Signed-off-by: Will Deacon 
Message-Id: <20250717090116.11987-9-will@kernel.org>
Signed-off-by: Michael S. Tsirkin

vhost/vsock: Allocate nonlinear SKBs for handling large receive buffers

2025-08-01T13:11:09+00:00

When receiving a packet from a guest, vhost_vsock_handle_tx_kick()
calls vhost_vsock_alloc_linear_skb() to allocate and fill an SKB with
the receive data. Unfortunately, these are always linear allocations and
can therefore result in significant pressure on kmalloc() considering
that the maximum packet size (VIRTIO_VSOCK_MAX_PKT_BUF_SIZE +
VIRTIO_VSOCK_SKB_HEADROOM) is a little over 64KiB, resulting in a 128KiB
allocation for each packet.

Rework the vsock SKB allocation so that, for sizes with page order
greater than PAGE_ALLOC_COSTLY_ORDER, a nonlinear SKB is allocated
instead with the packet header in the SKB and the receive data in the
fragments. Finally, add a debug warning if virtio_vsock_skb_rx_put() is
ever called on an SKB with a non-zero length, as this would be
destructive for the nonlinear case.

Reviewed-by: Stefano Garzarella 
Signed-off-by: Will Deacon 
Message-Id: <20250717090116.11987-8-will@kernel.org>
Signed-off-by: Michael S. Tsirkin

vsock/virtio: Move SKB allocation lower-bound check to callers

2025-08-01T13:11:09+00:00

virtio_vsock_alloc_linear_skb() checks that the requested size is at
least big enough for the packet header (VIRTIO_VSOCK_SKB_HEADROOM).

Of the three callers of virtio_vsock_alloc_linear_skb(), only
vhost_vsock_alloc_skb() can potentially pass a packet smaller than the
header size and, as it already has a check against the maximum packet
size, extend its bounds checking to consider the minimum packet size
and remove the check from virtio_vsock_alloc_linear_skb().

Reviewed-by: Stefano Garzarella 
Signed-off-by: Will Deacon 
Message-Id: <20250717090116.11987-7-will@kernel.org>
Signed-off-by: Michael S. Tsirkin

vsock/virtio: Rename virtio_vsock_alloc_skb()

2025-08-01T13:11:09+00:00

In preparation for nonlinear allocations for large SKBs, rename
virtio_vsock_alloc_skb() to virtio_vsock_alloc_linear_skb() to indicate
that it returns linear SKBs unconditionally and switch all callers over
to this new interface for now.

No functional change.

Reviewed-by: Stefano Garzarella 
Signed-off-by: Will Deacon 
Message-Id: <20250717090116.11987-6-will@kernel.org>
Signed-off-by: Michael S. Tsirkin

vsock/virtio: Move length check to callers of virtio_vsock_skb_rx_put()

2025-08-01T13:11:09+00:00

virtio_vsock_skb_rx_put() only calls skb_put() if the length in the
packet header is not zero even though skb_put() handles this case
gracefully.

Remove the functionally redundant check from virtio_vsock_skb_rx_put()
and, on the assumption that this is a worthwhile optimisation for
handling credit messages, augment the existing length checks in
virtio_transport_rx_work() to elide the call for zero-length payloads.
Since the callers all have the length, extend virtio_vsock_skb_rx_put()
to take it as an additional parameter rather than fish it back out of
the packet header.

Note that the vhost code already has similar logic in
vhost_vsock_alloc_skb().

Reviewed-by: Stefano Garzarella 
Signed-off-by: Will Deacon 
Message-Id: <20250717090116.11987-4-will@kernel.org>
Signed-off-by: Michael S. Tsirkin

vhost/vsock: Avoid allocating arbitrarily-sized SKBs

2025-08-01T13:11:09+00:00

vhost_vsock_alloc_skb() returns NULL for packets advertising a length
larger than VIRTIO_VSOCK_MAX_PKT_BUF_SIZE in the packet header. However,
this is only checked once the SKB has been allocated and, if the length
in the packet header is zero, the SKB may not be freed immediately.

Hoist the size check before the SKB allocation so that an iovec larger
than VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + the header size is rejected
outright. The subsequent check on the length field in the header can
then simply check that the allocated SKB is indeed large enough to hold
the packet.

Cc: 
Fixes: 71dc9ec9ac7d ("virtio/vsock: replace virtio_vsock_pkt with sk_buff")
Reviewed-by: Stefano Garzarella 
Signed-off-by: Will Deacon 
Message-Id: <20250717090116.11987-2-will@kernel.org>
Signed-off-by: Michael S. Tsirkin

vsock/virtio: add SIOCOUTQ support for all virtio based transports

2024-08-02T08:20:28+00:00

Introduce support for virtio_transport_unsent_bytes
ioctl for virtio_transport, vhost_vsock and vsock_loopback.

For all transports the unsent bytes counter is incremented
in virtio_transport_get_credit.

In virtio_transport (G2H) and in vhost-vsock (H2G) the counter
is decremented when the skbuff is consumed. In vsock_loopback the
same skbuff is passed from the transmitter to the receiver, so
the counter is decremented before queuing the skbuff to the
receiver.

Signed-off-by: Luigi Leonardi 
Reviewed-by: Stefano Garzarella 
Signed-off-by: David S. Miller

vhost/vsock: always initialize seqpacket_allow

2024-07-04T15:00:31+00:00

There are two issues around seqpacket_allow:
1. seqpacket_allow is not initialized when socket is
   created. Thus if features are never set, it will be
   read uninitialized.
2. if VIRTIO_VSOCK_F_SEQPACKET is set and then cleared,
   then seqpacket_allow will not be cleared appropriately
   (existing apps I know about don't usually do this but
    it's legal and there's no way to be sure no one relies
    on this).

To fix:
	- initialize seqpacket_allow after allocation
	- set it unconditionally in set_features

Reported-by: syzbot+6c21aeb59d0e82eb2782@syzkaller.appspotmail.com
Reported-by: Jeongjun Park 
Fixes: ced7b713711f ("vhost/vsock: support SEQPACKET for transport").
Tested-by: Arseny Krasnov 
Cc: David S. Miller 
Cc: Stefan Hajnoczi 
Message-ID: <20240422100010-mutt-send-email-mst@kernel.org>
Signed-off-by: Michael S. Tsirkin 
Acked-by: Jason Wang 
Reviewed-by: Stefano Garzarella 
Reviewed-by: Eugenio Pérez 
Acked-by: Jakub Kicinski

virtio/vsock: send credit update during setting SO_RCVLOWAT

2023-12-15T10:37:35+00:00

Send credit update message when SO_RCVLOWAT is updated and it is bigger
than number of bytes in rx queue. It is needed, because 'poll()' will
wait until number of bytes in rx queue will be not smaller than
O_RCVLOWAT, so kick sender to send more data. Otherwise mutual hungup
for tx/rx is possible: sender waits for free space and receiver is
waiting data in 'poll()'.

Rename 'set_rcvlowat' callback to 'notify_set_rcvlowat' and set
'sk->sk_rcvlowat' only in one place (i.e. 'vsock_set_rcvlowat'), so the
transport doesn't need to do it.

Fixes: b89d882dc9fc ("vsock/virtio: reduce credit update messages")
Signed-off-by: Arseniy Krasnov 
Reviewed-by: Stefano Garzarella 
Acked-by: Michael S. Tsirkin 
Signed-off-by: David S. Miller

vhost/vsock: support MSG_ZEROCOPY for transport

2023-10-15T12:19:42+00:00

Add 'msgzerocopy_allow()' callback for vhost transport.

Signed-off-by: Arseniy Krasnov 
Reviewed-by: Stefano Garzarella 
Signed-off-by: David S. Miller