git: 1bfd392b9e4d - main - vtnet: remove loader tunable fixup_needs_csum
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Date: Sun, 26 Apr 2026 09:46:16 UTC
The branch main has been updated by tuexen:
URL: https://cgit.FreeBSD.org/src/commit/?id=1bfd392b9e4dcddef3d80efaa517fafa648cd0b1
commit 1bfd392b9e4dcddef3d80efaa517fafa648cd0b1
Author: Timo Völker <timo.voelker@fh-muenster.de>
AuthorDate: 2026-04-26 09:42:38 +0000
Commit: Michael Tuexen <tuexen@FreeBSD.org>
CommitDate: 2026-04-26 09:42:38 +0000
vtnet: remove loader tunable fixup_needs_csum
Removes the deprecated loader tunable fixup_needs_csum. Removes also
the sysctl counter rx_csum_bad_offset that is no longer in use.
Reviewed by: tuexen
Event: Wiesbaden Hackathon 2026
Differential Revision: https://reviews.freebsd.org/D55588
---
share/man/man4/vtnet.4 | 24 +-----------
sys/arm/allwinner/if_awg.c | 14 +++----
sys/dev/virtio/network/if_vtnet.c | 78 ++++++---------------------------------
3 files changed, 21 insertions(+), 95 deletions(-)
diff --git a/share/man/man4/vtnet.4 b/share/man/man4/vtnet.4
index 926f504d8070..fad0257a2b10 100644
--- a/share/man/man4/vtnet.4
+++ b/share/man/man4/vtnet.4
@@ -22,7 +22,7 @@
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
-.Dd December 19, 2025
+.Dd April 26, 2026
.Dt VTNET 4
.Os
.Sh NAME
@@ -87,19 +87,6 @@ UDP.
This also implies that TCP segmentation offloading and large receive offload
are disabled.
The default value is 0.
-.It Va hw.vtnet.fixup_needs_csum
-.It Va hw.vtnet. Ns Ar X Ns Va .fixup_needs_csum
-This tunable enforces the calculation of a valid TCP or UDP checksum for
-packets received with
-.Dv VIRTIO_NET_HDR_F_NEEDS_CSUM
-being set in the
-.Va flags
-field of the structure
-.Vt struct virtio_net_hdr .
-It also marks the checksum as being correct in the mbuf packet header.
-The default value is 0.
-This tunable is deprecated and will be removed in
-.Fx 16 .
.It Va hw.vtnet.tso_disable
.It Va hw.vtnet. Ns Ar X Ns Va .tso_disable
This tunable disables TCP segmentation offloading.
@@ -174,9 +161,8 @@ offloading was received and this request failed.
The different reasons for the failure are counted by
.Va dev.vtnet. Ns Ar X Ns Va .rx_csum_inaccessible_ipproto ,
.Va dev.vtnet. Ns Ar X Ns Va .rx_csum_bad_ipproto ,
-.Va dev.vtnet. Ns Ar X Ns Va .rx_csum_bad_ethtype ,
and
-.Va dev.vtnet. Ns Ar X Ns Va .rx_csum_bad_offset .
+.Va dev.vtnet. Ns Ar X Ns Va .rx_csum_bad_ethtype .
.It Va dev.vtnet. Ns Ar X Ns Va .rxq Ns Ar Y Ns Va .csum
The number of times receive checksum offloading for UDP or TCP was performed.
.It Va dev.vtnet. Ns Ar X Ns Va .rxq Ns Ar Y Ns Va .ierrors
@@ -239,12 +225,6 @@ over all receive queues of the interface.
.It Va dev.vtnet. Ns Ar X Ns Va .rx_csum_inaccessible_ipproto
The number of times a packet with a request for receive or transmit checksum
offloading was received where the IP protocol was not accessible.
-.It Va dev.vtnet. Ns Ar X Ns Va .rx_csum_bad_offset
-The number of times fixing the checksum required by
-.Va hw.vtnet.fixup_needs_csum
-or
-.Va hw.vtnet. Ns Ar X Ns Va .fixup_needs_csum
-was attempted for a packet where the csum is not located in the first mbuf.
.It Va dev.vtnet. Ns Ar X Ns Va .rx_csum_bad_ipproto
The number of times a packet with a request for receive or transmit checksum
offloading was received where the IP protocol was neither TCP nor UDP.
diff --git a/sys/arm/allwinner/if_awg.c b/sys/arm/allwinner/if_awg.c
index c66aab9422b8..d5a6fdb96192 100644
--- a/sys/arm/allwinner/if_awg.c
+++ b/sys/arm/allwinner/if_awg.c
@@ -651,13 +651,13 @@ awg_encap(struct awg_softc *sc, struct mbuf **mp)
flags = TX_FIR_DESC;
status = 0;
- if ((m->m_pkthdr.csum_flags & CSUM_IP) != 0) {
- if ((m->m_pkthdr.csum_flags & (CSUM_TCP|CSUM_UDP)) != 0)
- csum_flags = TX_CHECKSUM_CTL_FULL;
- else
- csum_flags = TX_CHECKSUM_CTL_IP;
- flags |= (csum_flags << TX_CHECKSUM_CTL_SHIFT);
- }
+ if ((m->m_pkthdr.csum_flags & (CSUM_TCP|CSUM_UDP)) != 0)
+ csum_flags = TX_CHECKSUM_CTL_FULL;
+ else if ((m->m_pkthdr.csum_flags & CSUM_IP) != 0)
+ csum_flags = TX_CHECKSUM_CTL_IP;
+ else
+ csum_flags = 0;
+ flags |= (csum_flags << TX_CHECKSUM_CTL_SHIFT);
for (i = 0; i < nsegs; i++) {
sc->tx.segs++;
diff --git a/sys/dev/virtio/network/if_vtnet.c b/sys/dev/virtio/network/if_vtnet.c
index da89dea03f87..ef01833b9e03 100644
--- a/sys/dev/virtio/network/if_vtnet.c
+++ b/sys/dev/virtio/network/if_vtnet.c
@@ -135,7 +135,7 @@ static int vtnet_rxq_replace_buf(struct vtnet_rxq *, struct mbuf *, int);
static int vtnet_rxq_enqueue_buf(struct vtnet_rxq *, struct mbuf *);
static int vtnet_rxq_new_buf(struct vtnet_rxq *);
#if defined(INET) || defined(INET6)
-static int vtnet_rxq_csum_needs_csum(struct vtnet_rxq *, struct mbuf *,
+static void vtnet_rxq_csum_needs_csum(struct vtnet_rxq *, struct mbuf *,
bool, int, struct virtio_net_hdr *);
static void vtnet_rxq_csum_data_valid(struct vtnet_rxq *, struct mbuf *,
int);
@@ -273,11 +273,6 @@ static int vtnet_csum_disable = 0;
SYSCTL_INT(_hw_vtnet, OID_AUTO, csum_disable, CTLFLAG_RDTUN,
&vtnet_csum_disable, 0, "Disables receive and send checksum offload");
-static int vtnet_fixup_needs_csum = 0;
-SYSCTL_INT(_hw_vtnet, OID_AUTO, fixup_needs_csum, CTLFLAG_RDTUN,
- &vtnet_fixup_needs_csum, 0,
- "Calculate valid checksum for NEEDS_CSUM packets");
-
static int vtnet_tso_disable = 0;
SYSCTL_INT(_hw_vtnet, OID_AUTO, tso_disable, CTLFLAG_RDTUN,
&vtnet_tso_disable, 0, "Disables TSO");
@@ -1158,10 +1153,6 @@ vtnet_setup_interface(struct vtnet_softc *sc)
if_setcapabilitiesbit(ifp, IFCAP_RXCSUM, 0);
if_setcapabilitiesbit(ifp, IFCAP_RXCSUM_IPV6, 0);
- if (vtnet_tunable_int(sc, "fixup_needs_csum",
- vtnet_fixup_needs_csum) != 0)
- sc->vtnet_flags |= VTNET_FLAG_FIXUP_NEEDS_CSUM;
-
/* Support either "hardware" or software LRO. */
if_setcapabilitiesbit(ifp, IFCAP_LRO, 0);
}
@@ -1784,12 +1775,10 @@ vtnet_rxq_new_buf(struct vtnet_rxq *rxq)
}
#if defined(INET) || defined(INET6)
-static int
+static void
vtnet_rxq_csum_needs_csum(struct vtnet_rxq *rxq, struct mbuf *m, bool isipv6,
int protocol, struct virtio_net_hdr *hdr)
{
- struct vtnet_softc *sc;
-
/*
* The packet is likely from another VM on the same host or from the
* host that itself performed checksum offloading so Tx/Rx is basically
@@ -1800,57 +1789,18 @@ vtnet_rxq_csum_needs_csum(struct vtnet_rxq *rxq, struct mbuf *m, bool isipv6,
("%s: unsupported IP protocol %d", __func__, protocol));
/*
- * If the user don't want us to fix it up here by computing the
- * checksum, just forward the order to compute the checksum by setting
+ * Just forward the order to compute the checksum by setting
* the corresponding mbuf flag (e.g., CSUM_TCP).
*/
- sc = rxq->vtnrx_sc;
- if ((sc->vtnet_flags & VTNET_FLAG_FIXUP_NEEDS_CSUM) == 0) {
- switch (protocol) {
- case IPPROTO_TCP:
- m->m_pkthdr.csum_flags |=
- (isipv6 ? CSUM_TCP_IPV6 : CSUM_TCP);
- break;
- case IPPROTO_UDP:
- m->m_pkthdr.csum_flags |=
- (isipv6 ? CSUM_UDP_IPV6 : CSUM_UDP);
- break;
- }
- m->m_pkthdr.csum_data = hdr->csum_offset;
- return (0);
- }
-
- /*
- * Compute the checksum in the driver so the packet will contain a
- * valid checksum. The checksum is at csum_offset from csum_start.
- */
- int csum_off, csum_end;
- uint16_t csum;
-
- csum_off = hdr->csum_start + hdr->csum_offset;
- csum_end = csum_off + sizeof(uint16_t);
-
- /* Assume checksum will be in the first mbuf. */
- if (m->m_len < csum_end || m->m_pkthdr.len < csum_end) {
- sc->vtnet_stats.rx_csum_bad_offset++;
- return (1);
+ switch (protocol) {
+ case IPPROTO_TCP:
+ m->m_pkthdr.csum_flags |= (isipv6 ? CSUM_TCP_IPV6 : CSUM_TCP);
+ break;
+ case IPPROTO_UDP:
+ m->m_pkthdr.csum_flags |= (isipv6 ? CSUM_UDP_IPV6 : CSUM_UDP);
+ break;
}
-
- /*
- * Like in_delayed_cksum()/in6_delayed_cksum(), compute the
- * checksum and write it at the specified offset. We could
- * try to verify the packet: csum_start should probably
- * correspond to the start of the TCP/UDP header.
- *
- * BMV: Need to properly handle UDP with zero checksum. Is
- * the IPv4 header checksum implicitly validated?
- */
- csum = in_cksum_skip(m, m->m_pkthdr.len, hdr->csum_start);
- *(uint16_t *)(mtodo(m, csum_off)) = csum;
- m->m_pkthdr.csum_flags |= CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
- m->m_pkthdr.csum_data = 0xFFFF;
-
- return (0);
+ m->m_pkthdr.csum_data = hdr->csum_offset;
}
static void
@@ -1934,8 +1884,7 @@ vtnet_rxq_csum(struct vtnet_rxq *rxq, struct mbuf *m,
}
if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM)
- return (vtnet_rxq_csum_needs_csum(rxq, m, isipv6, protocol,
- hdr));
+ vtnet_rxq_csum_needs_csum(rxq, m, isipv6, protocol, hdr);
else /* VIRTIO_NET_HDR_F_DATA_VALID */
vtnet_rxq_csum_data_valid(rxq, m, protocol);
@@ -4354,9 +4303,6 @@ vtnet_setup_stat_sysctl(struct sysctl_ctx_list *ctx,
SYSCTL_ADD_UQUAD(ctx, child, OID_AUTO, "rx_csum_bad_ipproto",
CTLFLAG_RD | CTLFLAG_STATS, &stats->rx_csum_bad_ipproto,
"Received checksum offloaded buffer with incorrect IP protocol");
- SYSCTL_ADD_UQUAD(ctx, child, OID_AUTO, "rx_csum_bad_offset",
- CTLFLAG_RD | CTLFLAG_STATS, &stats->rx_csum_bad_offset,
- "Received checksum offloaded buffer with incorrect offset");
SYSCTL_ADD_UQUAD(ctx, child, OID_AUTO, "rx_csum_inaccessible_ipproto",
CTLFLAG_RD | CTLFLAG_STATS, &stats->rx_csum_inaccessible_ipproto,
"Received checksum offloaded buffer with inaccessible IP protocol");