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vio(4): tso
On Tue, Apr 09, 2024 at 04:31:10PM +0200, Alexander Bluhm wrote:
> On Tue, Apr 09, 2024 at 02:51:27PM +0200, jan@openbsd.org wrote:
> > ok?
>
> Some remarks.
>
> > +void
> > +vio_tx_offload(struct virtio_net_hdr *hdr, struct mbuf *m)
> > +{
> > + struct ether_extracted ext;
> > +
> > + /*
> > + * Checksum Offload
> > + */
> > +
> > + if (!ISSET(m->m_pkthdr.csum_flags, M_TCP_CSUM_OUT) &&
> > + !ISSET(m->m_pkthdr.csum_flags, M_UDP_CSUM_OUT))
> > + return;
> > +
> > + ether_extract_headers(m, &ext);
> > +
> > + /* Consistency Checks */
> > + if ((!ext.ip4 && !ext.ip6) || (!ext.tcp && !ext.udp))
> > + return;
> > +
> > + if (ISSET(m->m_pkthdr.csum_flags, M_TCP_CSUM_OUT) &&
> > + ISSET(m->m_pkthdr.csum_flags, M_UDP_CSUM_OUT))
> > + return;
>
> I think this M_TCP_CSUM_OUT M_UDP_CSUM_OUT check is not necessary.
done
> > +
> > + if ((ext.tcp && !ISSET(m->m_pkthdr.csum_flags, M_TCP_CSUM_OUT)) ||
> > + (ext.udp && !ISSET(m->m_pkthdr.csum_flags, M_UDP_CSUM_OUT)))
> > + return;
> > +
> > + if (ext.udp && ISSET(m->m_pkthdr.csum_flags, M_TCP_TSO)) {
> > + tcpstat_inc(tcps_outbadtso);
> > + return;
> > + }
>
> This M_TCP_TSO block should check for !ext.tcp instead of ext.udp.
> And it can be moved down. Then checksum offloading works even if
> TSO is inconsistent.
done
> > +
> > + hdr->csum_start = sizeof(*ext.eh);
> > +#if NVLAN > 0
> > + if (ext.evh)
> > + hdr->csum_start = sizeof(*ext.evh);
> > +#endif
> > + hdr->csum_start += ext.iphlen;
> > +
> > + if (ext.tcp)
> > + hdr->csum_offset = offsetof(struct tcphdr, th_sum);
> > + else if (ext.udp)
> > + hdr->csum_offset = offsetof(struct udphdr, uh_sum);
> > +
> > + hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
> > +
> > + /*
> > + * TCP Segmentation Offload
> > + */
> > +
> > + if (!ISSET(m->m_pkthdr.csum_flags, M_TCP_TSO))
> > + return;
> > +
>
> If you add this block here, I think all cases are covered.
>
> if (!ext.tcp) {
> tcpstat_inc(tcps_outbadtso);
> return;
> }
done
ok?
Thanks,
Jan
Index: dev/pv/if_vio.c
===================================================================
RCS file: /cvs/src/sys/dev/pv/if_vio.c,v
diff -u -p -r1.31 if_vio.c
--- dev/pv/if_vio.c 14 Feb 2024 22:41:48 -0000 1.31
+++ dev/pv/if_vio.c 9 Apr 2024 18:21:45 -0000
@@ -43,12 +43,15 @@
#include <net/if.h>
#include <net/if_media.h>
+#include <net/route.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <netinet/tcp.h>
+#include <netinet/tcp_timer.h>
+#include <netinet/tcp_var.h>
#include <netinet/udp.h>
#if NBPFILTER > 0
@@ -537,6 +540,9 @@ vio_attach(struct device *parent, struct
VIRTIO_NET_F_MRG_RXBUF | VIRTIO_NET_F_CSUM |
VIRTIO_F_RING_EVENT_IDX | VIRTIO_NET_F_GUEST_CSUM;
+ vsc->sc_driver_features |= VIRTIO_NET_F_HOST_TSO4;
+ vsc->sc_driver_features |= VIRTIO_NET_F_HOST_TSO6;
+
virtio_negotiate_features(vsc, virtio_net_feature_names);
if (virtio_has_feature(vsc, VIRTIO_NET_F_MAC)) {
vio_get_lladdr(&sc->sc_ac, vsc);
@@ -553,9 +559,9 @@ vio_attach(struct device *parent, struct
sc->sc_hdr_size = offsetof(struct virtio_net_hdr, num_buffers);
}
if (virtio_has_feature(vsc, VIRTIO_NET_F_MRG_RXBUF))
- ifp->if_hardmtu = 16000; /* arbitrary limit */
+ ifp->if_hardmtu = MAXMCLBYTES;
else
- ifp->if_hardmtu = MCLBYTES - sc->sc_hdr_size - ETHER_HDR_LEN;
+ ifp->if_hardmtu = MAXMCLBYTES - sc->sc_hdr_size - ETHER_HDR_LEN;
if (virtio_alloc_vq(vsc, &sc->sc_vq[VQRX], 0, MCLBYTES, 2, "rx") != 0)
goto err;
@@ -595,6 +601,10 @@ vio_attach(struct device *parent, struct
if (virtio_has_feature(vsc, VIRTIO_NET_F_CSUM))
ifp->if_capabilities |= IFCAP_CSUM_TCPv4|IFCAP_CSUM_UDPv4|
IFCAP_CSUM_TCPv6|IFCAP_CSUM_UDPv6;
+ if (virtio_has_feature(vsc, VIRTIO_NET_F_HOST_TSO4))
+ ifp->if_capabilities |= IFCAP_TSOv4;
+ if (virtio_has_feature(vsc, VIRTIO_NET_F_HOST_TSO6))
+ ifp->if_capabilities |= IFCAP_TSOv6;
ifq_init_maxlen(&ifp->if_snd, vsc->sc_vqs[1].vq_num - 1);
ifmedia_init(&sc->sc_media, 0, vio_media_change, vio_media_status);
ifmedia_add(&sc->sc_media, IFM_ETHER | IFM_AUTO, 0, NULL);
@@ -714,6 +724,85 @@ vio_stop(struct ifnet *ifp, int disable)
}
}
+static inline uint16_t
+vio_cksum_update(uint32_t cksum, uint16_t paylen)
+{
+ /* Add payload length */
+ cksum += paylen;
+
+ /* Fold back to 16 bit */
+ cksum += cksum >> 16;
+
+ return (uint16_t)(cksum);
+}
+
+void
+vio_tx_offload(struct virtio_net_hdr *hdr, struct mbuf *m)
+{
+ struct ether_extracted ext;
+
+ /*
+ * Checksum Offload
+ */
+
+ if (!ISSET(m->m_pkthdr.csum_flags, M_TCP_CSUM_OUT) &&
+ !ISSET(m->m_pkthdr.csum_flags, M_UDP_CSUM_OUT))
+ return;
+
+ ether_extract_headers(m, &ext);
+
+ /* Consistency Checks */
+ if ((!ext.ip4 && !ext.ip6) || (!ext.tcp && !ext.udp))
+ return;
+
+ if ((ext.tcp && !ISSET(m->m_pkthdr.csum_flags, M_TCP_CSUM_OUT)) ||
+ (ext.udp && !ISSET(m->m_pkthdr.csum_flags, M_UDP_CSUM_OUT)))
+ return;
+
+ hdr->csum_start = sizeof(*ext.eh);
+#if NVLAN > 0
+ if (ext.evh)
+ hdr->csum_start = sizeof(*ext.evh);
+#endif
+ hdr->csum_start += ext.iphlen;
+
+ if (ext.tcp)
+ hdr->csum_offset = offsetof(struct tcphdr, th_sum);
+ else if (ext.udp)
+ hdr->csum_offset = offsetof(struct udphdr, uh_sum);
+
+ hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
+
+ /*
+ * TCP Segmentation Offload
+ */
+
+ if (!ISSET(m->m_pkthdr.csum_flags, M_TCP_TSO))
+ return;
+
+ if (!ext.tcp) {
+ tcpstat_inc(tcps_outbadtso);
+ return;
+ }
+
+ hdr->hdr_len = hdr->csum_start + ext.tcphlen;
+ hdr->gso_size = m->m_pkthdr.ph_mss;
+
+ if (ext.ip4)
+ hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
+#ifdef INET6
+ else if (ext.ip6)
+ hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
+#endif
+
+ /* VirtIO-Net need pseudo header cksum with IP-payload length for TSO */
+ ext.tcp->th_sum = vio_cksum_update(ext.tcp->th_sum,
+ htons(ext.iplen - ext.iphlen));
+
+ tcpstat_add(tcps_outpkttso,
+ (ext.paylen + m->m_pkthdr.ph_mss - 1) / m->m_pkthdr.ph_mss);
+}
+
void
vio_start(struct ifnet *ifp)
{
@@ -750,24 +839,7 @@ again:
hdr = &sc->sc_tx_hdrs[slot];
memset(hdr, 0, sc->sc_hdr_size);
- if (m->m_pkthdr.csum_flags & (M_TCP_CSUM_OUT|M_UDP_CSUM_OUT)) {
- struct ether_extracted ext;
-
- ether_extract_headers(m, &ext);
- hdr->csum_start = sizeof(*ext.eh);
-#if NVLAN > 0
- if (ext.evh)
- hdr->csum_start = sizeof(*ext.evh);
-#endif
- if (m->m_pkthdr.csum_flags & M_TCP_CSUM_OUT)
- hdr->csum_offset = offsetof(struct tcphdr, th_sum);
- else
- hdr->csum_offset = offsetof(struct udphdr, uh_sum);
-
- if (ext.ip4 || ext.ip6)
- hdr->csum_start += ext.iphlen;
- hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
- }
+ vio_tx_offload(hdr, m);
r = vio_encap(sc, slot, m);
if (r != 0) {
vio(4): tso