On Fri, Sep 05, 2025 at 05:49:33PM +0200, Laurent Vivier wrote:

The vhost-user specification states that VHOST_USER_GET_QUEUE_NUM should return the maximum number of queues supported by the back-end, not the number of virtqueues. Since each queue pair consists of RX and TX virtqueues, we need to divide VHOST_USER_MAX_QUEUES by 2 to get the correct queue count.

Also rename VHOST_USER_MAX_QUEUES to VHOST_USER_MAX_VQS throughout the codebase to better reflect that it represents the maximum number of virtqueues, not queue pairs.

Signed-off-by: Laurent Vivier

Reviewed-by: David Gibson

--- vhost_user.c | 16 +++++++++------- virtio.h | 4 ++-- 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/vhost_user.c b/vhost_user.c index f97ec6064cac..fa343a86fac2 100644 --- a/vhost_user.c +++ b/vhost_user.c @@ -345,7 +345,7 @@ static void vu_set_enable_all_rings(struct vu_dev *vdev, bool enable) { uint16_t i;

- for (i = 0; i < VHOST_USER_MAX_QUEUES; i++) + for (i = 0; i < VHOST_USER_MAX_VQS; i++) vdev->vq[i].enable = enable; }

@@ -477,7 +477,7 @@ static bool vu_set_mem_table_exec(struct vu_dev *vdev, close(vmsg->fds[i]); }

- for (i = 0; i < VHOST_USER_MAX_QUEUES; i++) { + for (i = 0; i < VHOST_USER_MAX_VQS; i++) { if (vdev->vq[i].vring.desc) { if (map_ring(vdev, &vdev->vq[i])) die("remapping queue %d during setmemtable", i); @@ -770,7 +770,7 @@ static void vu_check_queue_msg_file(struct vhost_user_msg *vmsg) bool nofd = vmsg->payload.u64 & VHOST_USER_VRING_NOFD_MASK; int idx = vmsg->payload.u64 & VHOST_USER_VRING_IDX_MASK;

- if (idx >= VHOST_USER_MAX_QUEUES) + if (idx >= VHOST_USER_MAX_VQS) die("Invalid vhost-user queue index: %u", idx);

if (nofd) { @@ -939,7 +939,9 @@ static bool vu_get_queue_num_exec(struct vu_dev *vdev, { (void)vdev;

- vmsg_set_reply_u64(vmsg, VHOST_USER_MAX_QUEUES); + vmsg_set_reply_u64(vmsg, VHOST_USER_MAX_VQS / 2); + + debug("VHOST_USER_MAX_VQS %u", VHOST_USER_MAX_VQS / 2);

return true; } @@ -960,7 +962,7 @@ static bool vu_set_vring_enable_exec(struct vu_dev *vdev, debug("State.index: %u", idx); debug("State.enable: %u", enable);

- if (idx >= VHOST_USER_MAX_QUEUES) + if (idx >= VHOST_USER_MAX_VQS) die("Invalid vring_enable index: %u", idx);

vdev->vq[idx].enable = enable; @@ -1052,7 +1054,7 @@ void vu_init(struct ctx *c)

c->vdev = &vdev_storage; c->vdev->context = c; - for (i = 0; i < VHOST_USER_MAX_QUEUES; i++) { + for (i = 0; i < VHOST_USER_MAX_VQS; i++) { c->vdev->vq[i] = (struct vu_virtq){ .call_fd = -1, .kick_fd = -1, @@ -1075,7 +1077,7 @@ void vu_cleanup(struct vu_dev *vdev) { unsigned int i;

- for (i = 0; i < VHOST_USER_MAX_QUEUES; i++) { + for (i = 0; i < VHOST_USER_MAX_VQS; i++) { struct vu_virtq *vq = &vdev->vq[i];

vq->started = false; diff --git a/virtio.h b/virtio.h index b55cc4042521..12caaa0b6def 100644 --- a/virtio.h +++ b/virtio.h @@ -88,7 +88,7 @@ struct vu_dev_region { uint64_t mmap_addr; };

-#define VHOST_USER_MAX_QUEUES 2 +#define VHOST_USER_MAX_VQS 2

/* * Set a reasonable maximum number of ram slots, which will be supported by @@ -121,7 +121,7 @@ struct vdev_memory { struct vu_dev { struct ctx *context; struct vdev_memory memory; - struct vu_virtq vq[VHOST_USER_MAX_QUEUES]; + struct vu_virtq vq[VHOST_USER_MAX_VQS]; uint64_t features; uint64_t protocol_features; int log_call_fd; -- 2.50.1

-- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson

On Fri, Sep 05, 2025 at 05:49:34PM +0200, Laurent Vivier wrote:

Pass the virtqueue pointer to udp_vu_sock_recv() to enable proper queue selection for multiqueue support. This ensures that received packets are processed on the same virtqueue as the caller.

Signed-off-by: Laurent Vivier

Reviewed-by: David Gibson Regardless of future plans, I think it's cleaner to pass the vq than to rederive it.

--- udp_vu.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/udp_vu.c b/udp_vu.c index 2fb7b900ca31..099677f914e7 100644 --- a/udp_vu.c +++ b/udp_vu.c @@ -60,16 +60,17 @@ static size_t udp_vu_hdrlen(bool v6) /** * udp_vu_sock_recv() - Receive datagrams from socket into vhost-user buffers * @c: Execution context + * @vq: virtqueue to use to receive data * @s: Socket to receive from * @v6: Set for IPv6 connections * @dlen: Size of received data (output) * * Return: number of iov entries used to store the datagram */ -static int udp_vu_sock_recv(const struct ctx *c, int s, bool v6, ssize_t *dlen) +static int udp_vu_sock_recv(const struct ctx *c, struct vu_virtq *vq, int s, + bool v6, ssize_t *dlen) { - struct vu_dev *vdev = c->vdev; - struct vu_virtq *vq = &vdev->vq[VHOST_USER_RX_QUEUE]; + const struct vu_dev *vdev = c->vdev; int iov_cnt, idx, iov_used; struct msghdr msg = { 0 }; size_t off, hdrlen; @@ -210,7 +211,7 @@ void udp_vu_sock_to_tap(const struct ctx *c, int s, int n, flow_sidx_t tosidx) ssize_t dlen; int iov_used;

- iov_used = udp_vu_sock_recv(c, s, v6, &dlen); + iov_used = udp_vu_sock_recv(c, vq, s, v6, &dlen); if (iov_used <= 0) break;

-- 2.50.1

-- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson

On Fri, Sep 05, 2025 at 05:49:35PM +0200, Laurent Vivier wrote:

Pass the virtqueue pointer to tcp_vu_sock_recv() to enable proper queue selection for multiqueue support. This ensures that received packets are processed on the same virtqueue as the caller.

Signed-off-by: Laurent Vivier

Reviewed-by: David Gibson

--- tcp_vu.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tcp_vu.c b/tcp_vu.c index cb39bc20355b..c6b5b91ec266 100644 --- a/tcp_vu.c +++ b/tcp_vu.c @@ -171,6 +171,7 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)

/** tcp_vu_sock_recv() - Receive datastream from socket into vhost-user buffers * @c: Execution context + * @vq: virtqueue to use to receive data * @conn: Connection pointer * @v6: Set for IPv6 connections * @already_sent: Number of bytes already sent @@ -181,13 +182,12 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags) * Return: number of bytes received from the socket, or a negative error code * on failure. */ -static ssize_t tcp_vu_sock_recv(const struct ctx *c, +static ssize_t tcp_vu_sock_recv(const struct ctx *c, struct vu_virtq *vq, const struct tcp_tap_conn *conn, bool v6, uint32_t already_sent, size_t fillsize, int *iov_cnt, int *head_cnt) { - struct vu_dev *vdev = c->vdev; - struct vu_virtq *vq = &vdev->vq[VHOST_USER_RX_QUEUE]; + const struct vu_dev *vdev = c->vdev; struct msghdr mh_sock = { 0 }; uint16_t mss = MSS_GET(conn); int s = conn->sock; @@ -398,7 +398,7 @@ int tcp_vu_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn) /* collect the buffers from vhost-user and fill them with the * data from the socket */ - len = tcp_vu_sock_recv(c, conn, v6, already_sent, fillsize, + len = tcp_vu_sock_recv(c, vq, conn, v6, already_sent, fillsize, &iov_cnt, &head_cnt); if (len < 0) { if (len != -EAGAIN && len != -EWOULDBLOCK) { -- 2.50.1

-- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson