Legacy virtio used two different header formats: struct virtio_net_hdr
(10 bytes) when VIRTIO_NET_F_MRG_RXBUF was not negotiated, and
struct virtio_net_hdr_mrg_rxbuf (12 bytes) when it was. The
num_buffers field only existed in the larger header.
Modern virtio (VIRTIO_F_VERSION_1, i.e. virtio 1.0+) always uses the
12-byte struct virtio_net_hdr_mrg_rxbuf header regardless of whether
VIRTIO_NET_F_MRG_RXBUF is negotiated, so num_buffers is always present
in the header. passt only supports modern virtio and dies if
VIRTIO_F_VERSION_1 is not negotiated (vhost_user.c), and VNET_HLEN is
unconditionally defined as sizeof(struct virtio_net_hdr_mrg_rxbuf).
The virtio specification (v1.1, section 5.1.6) requires that:
"The device MUST set num_buffers to 1 if VIRTIO_NET_F_MRG_RXBUF has
not been negotiated."
vu_set_vnethdr() only set num_buffers when VIRTIO_NET_F_MRG_RXBUF was
negotiated. When it was not, num_buffers was left uninitialised,
violating the spec.
Since vu_collect() already limits buffer collection to a single element
when VIRTIO_NET_F_MRG_RXBUF is not negotiated, num_buffers passed by
callers is guaranteed to be 1 in that case. We can therefore
unconditionally set num_buffers, which makes the vdev parameter
unnecessary.
Drop the vdev parameter from vu_set_vnethdr() and update all callers.
Signed-off-by: Laurent Vivier
---
tcp_vu.c | 4 ++--
udp_vu.c | 2 +-
vu_common.c | 13 ++++++-------
vu_common.h | 4 +---
4 files changed, 10 insertions(+), 13 deletions(-)
diff --git a/tcp_vu.c b/tcp_vu.c
index bb05fbf45826..88be232dca66 100644
--- a/tcp_vu.c
+++ b/tcp_vu.c
@@ -97,7 +97,7 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
ASSERT(flags_elem[0].in_sg[0].iov_len >=
MAX(hdrlen + sizeof(*opts), ETH_ZLEN + VNET_HLEN));
- vu_set_vnethdr(vdev, flags_elem[0].in_sg[0].iov_base, 1);
+ vu_set_vnethdr(flags_elem[0].in_sg[0].iov_base, 1);
eh = vu_eth(flags_elem[0].in_sg[0].iov_base);
@@ -452,7 +452,7 @@ int tcp_vu_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn)
bool push = i == head_cnt - 1;
size_t l2len;
- vu_set_vnethdr(vdev, iov->iov_base, buf_cnt);
+ vu_set_vnethdr(iov->iov_base, buf_cnt);
/* The IPv4 header checksum varies only with dlen */
if (previous_dlen != dlen)
diff --git a/udp_vu.c b/udp_vu.c
index 51f3718f5925..3520f89e5671 100644
--- a/udp_vu.c
+++ b/udp_vu.c
@@ -127,7 +127,7 @@ static int udp_vu_sock_recv(const struct ctx *c, struct vu_virtq *vq, int s,
l2len = *dlen + hdrlen - VNET_HLEN;
vu_pad(&iov_vu[0], l2len);
- vu_set_vnethdr(vdev, iov_vu[0].iov_base, iov_used);
+ vu_set_vnethdr(iov_vu[0].iov_base, iov_used);
/* release unused buffers */
vu_queue_rewind(vq, iov_cnt - iov_used);
diff --git a/vu_common.c b/vu_common.c
index aa14598ea028..5f2ce18e5b71 100644
--- a/vu_common.c
+++ b/vu_common.c
@@ -121,17 +121,16 @@ int vu_collect(const struct vu_dev *vdev, struct vu_virtq *vq,
/**
* vu_set_vnethdr() - set virtio-net headers
- * @vdev: vhost-user device
* @vnethdr: Address of the header to set
* @num_buffers: Number of guest buffers of the frame
*/
-void vu_set_vnethdr(const struct vu_dev *vdev,
- struct virtio_net_hdr_mrg_rxbuf *vnethdr,
- int num_buffers)
+void vu_set_vnethdr(struct virtio_net_hdr_mrg_rxbuf *vnethdr, int num_buffers)
{
vnethdr->hdr = VU_HEADER;
- if (vu_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
- vnethdr->num_buffers = htole16(num_buffers);
+ /* Note: if VIRTIO_NET_F_MRG_RXBUF is not negotiated,
+ * num_buffers must be 1
+ */
+ vnethdr->num_buffers = htole16(num_buffers);
}
/**
@@ -269,7 +268,7 @@ int vu_send_single(const struct ctx *c, const void *buf, size_t size)
goto err;
}
- vu_set_vnethdr(vdev, in_sg[0].iov_base, elem_cnt);
+ vu_set_vnethdr(in_sg[0].iov_base, elem_cnt);
total -= VNET_HLEN;
diff --git a/vu_common.h b/vu_common.h
index 052aff710502..20868a7f62ce 100644
--- a/vu_common.h
+++ b/vu_common.h
@@ -49,9 +49,7 @@ void vu_init_elem(struct vu_virtq_element *elem, struct iovec *iov,
int vu_collect(const struct vu_dev *vdev, struct vu_virtq *vq,
struct vu_virtq_element *elem, int max_elem, size_t size,
size_t *collected);
-void vu_set_vnethdr(const struct vu_dev *vdev,
- struct virtio_net_hdr_mrg_rxbuf *vnethdr,
- int num_buffers);
+void vu_set_vnethdr(struct virtio_net_hdr_mrg_rxbuf *vnethdr, int num_buffers);
void vu_flush(const struct vu_dev *vdev, struct vu_virtq *vq,
struct vu_virtq_element *elem, int elem_cnt);
void vu_kick_cb(struct vu_dev *vdev, union epoll_ref ref,
--
2.53.0