kernel/linux.git/include/linux/virtio_vsock.h, branch v6.6.132

vsock/virtio: Resize receive buffers so that each SKB fits in a 4K page

2025-08-28T14:28:25+00:00

[ Upstream commit 03a92f036a04fed2b00d69f5f46f1a486e70dc5c ] When allocating receive buffers for the vsock virtio RX virtqueue, an SKB is allocated with a 4140 data payload (the 44-byte packet header + VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE). Even when factoring in the SKB overhead, the resulting 8KiB allocation thanks to the rounding in kmalloc_reserve() is wasteful (~3700 unusable bytes) and results in a higher-order page allocation on systems with 4KiB pages just for the sake of a few hundred bytes of packet data. Limit the vsock virtio RX buffers to 4KiB per SKB, resulting in much better memory utilisation and removing the need to allocate higher-order pages entirely. Reviewed-by: Stefano Garzarella Signed-off-by: Will Deacon Message-Id: <20250717090116.11987-5-will@kernel.org> Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin

virtio/vsock: send credit update during setting SO_RCVLOWAT

2024-01-25T23:35:26+00:00

[ Upstream commit 0fe1798968115488c0c02f4633032a015b1faf97 ] 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 Signed-off-by: Sasha Levin

vsock: support sockmap

2023-03-29T07:19:38+00:00

This patch adds sockmap support for vsock sockets. It is intended to be usable by all transports, but only the virtio and loopback transports are implemented. SOCK_STREAM, SOCK_DGRAM, and SOCK_SEQPACKET are all supported. Signed-off-by: Bobby Eshleman Acked-by: Michael S. Tsirkin Reviewed-by: Stefano Garzarella Signed-off-by: David S. Miller

virtio/vsock: replace virtio_vsock_pkt with sk_buff

2023-01-16T13:26:33+00:00

This commit changes virtio/vsock to use sk_buff instead of virtio_vsock_pkt. Beyond better conforming to other net code, using sk_buff allows vsock to use sk_buff-dependent features in the future (such as sockmap) and improves throughput. This patch introduces the following performance changes: Tool: Uperf Env: Phys Host + L1 Guest Payload: 64k Threads: 16 Test Runs: 10 Type: SOCK_STREAM Before: commit b7bfaa761d760 ("Linux 6.2-rc3") Before ------ g2h: 16.77Gb/s h2g: 10.56Gb/s After ----- g2h: 21.04Gb/s h2g: 10.76Gb/s Signed-off-by: Bobby Eshleman Reviewed-by: Stefano Garzarella Signed-off-by: David S. Miller

virtio/vsock: rest of SOCK_SEQPACKET support

2021-06-11T20:32:47+00:00

Small updates to make SOCK_SEQPACKET work: 1) Send SHUTDOWN on socket close for SEQPACKET type. 2) Set SEQPACKET packet type during send. 3) Set 'VIRTIO_VSOCK_SEQ_EOR' bit in flags for last packet of message. 4) Implement data check function for SEQPACKET. 5) Check for max datagram size. Signed-off-by: Arseny Krasnov Signed-off-by: David S. Miller

virtio/vsock: dequeue callback for SOCK_SEQPACKET

2021-06-11T20:32:47+00:00

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. Signed-off-by: Arseny Krasnov Signed-off-by: David S. Miller

vsock/virtio: fix multiple packet delivery to monitoring devices

2020-04-27T17:18:01+00:00

In virtio_transport.c, if the virtqueue is full, the transmitting packet is queued up and it will be sent in the next iteration. This causes the same packet to be delivered multiple times to monitoring devices. We want to continue to deliver packets to monitoring devices before it is put in the virtqueue, to avoid that replies can appear in the packet capture before the transmitted packet. This patch fixes the issue, adding a new flag (tap_delivered) in struct virtio_vsock_pkt, to check if the packet is already delivered to monitoring devices. In vhost/vsock.c, we are splitting packets, so we must set 'tap_delivered' to false when we queue up the same virtio_vsock_pkt to handle the remaining bytes. Signed-off-by: Stefano Garzarella Signed-off-by: David S. Miller

vsock: handle buffer_size sockopts in the core

2019-11-15T02:12:18+00:00

virtio_transport and vmci_transport handle the buffer_size sockopts in a very similar way. In order to support multiple transports, this patch moves this handling in the core to allow the user to change the options also if the socket is not yet assigned to any transport. This patch also adds the '.notify_buffer_size' callback in the 'struct virtio_transport' in order to inform the transport, when the buffer_size is changed by the user. It is also useful to limit the 'buffer_size' requested (e.g. virtio transports). Acked-by: Dexuan Cui Reviewed-by: Stefan Hajnoczi Reviewed-by: Jorgen Hansen Signed-off-by: Stefano Garzarella Signed-off-by: David S. Miller

vsock/virtio: add transport parameter to the virtio_transport_reset_no_sock()

2019-11-15T02:12:18+00:00

We are going to add 'struct vsock_sock *' parameter to virtio_transport_get_ops(). In some cases, like in the virtio_transport_reset_no_sock(), we don't have any socket assigned to the packet received, so we can't use the virtio_transport_get_ops(). In order to allow virtio_transport_reset_no_sock() to use the '.send_pkt' callback from the 'vhost_transport' or 'virtio_transport', we add the 'struct virtio_transport *' to it and to its caller: virtio_transport_recv_pkt(). We moved the 'vhost_transport' and 'virtio_transport' definition, to pass their address to the virtio_transport_recv_pkt(). Reviewed-by: Stefan Hajnoczi Signed-off-by: Stefano Garzarella Signed-off-by: David S. Miller

vsock/virtio: remove unused 'work' field from 'struct virtio_vsock_pkt'

2019-10-28T08:25:04+00:00

The 'work' field was introduced with commit 06a8fc78367d0 ("VSOCK: Introduce virtio_vsock_common.ko") but it is never used in the code, so we can remove it to save memory allocated in the per-packet 'struct virtio_vsock_pkt' Suggested-by: Michael S. Tsirkin Signed-off-by: Stefano Garzarella Signed-off-by: Michael S. Tsirkin