Michael S. Tsirkin
2018-Apr-11 22:49 UTC
[PATCH net-next 1/5] virtio: Add support for SCTP checksum offloading
On Mon, Apr 02, 2018 at 09:40:02AM -0400, Vladislav Yasevich wrote:> To support SCTP checksum offloading, we need to add a new feature > to virtio_net, so we can negotiate support between the hypervisor > and the guest. > > The signalling to the guest that an alternate checksum needs to > be used is done via a new flag in the virtio_net_hdr. If the > flag is set, the host will know to perform an alternate checksum > calculation, which right now is only CRC32c. > > Signed-off-by: Vladislav Yasevich <vyasevic at redhat.com> > --- > drivers/net/virtio_net.c | 11 ++++++++--- > include/linux/virtio_net.h | 6 ++++++ > include/uapi/linux/virtio_net.h | 2 ++ > 3 files changed, 16 insertions(+), 3 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 7b187ec..b601294 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -2724,9 +2724,14 @@ static int virtnet_probe(struct virtio_device *vdev) > /* Do we support "hardware" checksums? */ > if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) { > /* This opens up the world of extra features. */ > - dev->hw_features |= NETIF_F_HW_CSUM | NETIF_F_SG; > + netdev_features_t sctp = 0; > + > + if (virtio_has_feature(vdev, VIRTIO_NET_F_SCTP_CSUM)) > + sctp |= NETIF_F_SCTP_CRC; > + > + dev->hw_features |= NETIF_F_HW_CSUM | NETIF_F_SG | sctp; > if (csum) > - dev->features |= NETIF_F_HW_CSUM | NETIF_F_SG; > + dev->features |= NETIF_F_HW_CSUM | NETIF_F_SG | sctp; > > if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) { > dev->hw_features |= NETIF_F_TSO > @@ -2952,7 +2957,7 @@ static struct virtio_device_id id_table[] = { > }; > > #define VIRTNET_FEATURES \ > - VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM, \ > + VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM, VIRTIO_NET_F_SCTP_CSUM, \ > VIRTIO_NET_F_MAC, \ > VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6, \ > VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6, \ > diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h > index f144216..2e7a64a 100644 > --- a/include/linux/virtio_net.h > +++ b/include/linux/virtio_net.h > @@ -39,6 +39,9 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb, > > if (!skb_partial_csum_set(skb, start, off)) > return -EINVAL; > + > + if (hdr->flags & VIRTIO_NET_HDR_F_CSUM_NOT_INET) > + skb->csum_not_inet = 1; > } > > if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { > @@ -96,6 +99,9 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, > hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID; > } /* else everything is zero */ > > + if (skb->csum_not_inet) > + hdr->flags &= VIRTIO_NET_HDR_F_CSUM_NOT_INET; > + > return 0; > } > > diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h > index 5de6ed3..3f279c8 100644 > --- a/include/uapi/linux/virtio_net.h > +++ b/include/uapi/linux/virtio_net.h > @@ -36,6 +36,7 @@ > #define VIRTIO_NET_F_GUEST_CSUM 1 /* Guest handles pkts w/ partial csum */ > #define VIRTIO_NET_F_CTRL_GUEST_OFFLOADS 2 /* Dynamic offload configuration. */ > #define VIRTIO_NET_F_MTU 3 /* Initial MTU advice */ > +#define VIRTIO_NET_F_SCTP_CSUM 4 /* SCTP checksum offload support */ > #define VIRTIO_NET_F_MAC 5 /* Host has given MAC address. */ > #define VIRTIO_NET_F_GUEST_TSO4 7 /* Guest can handle TSOv4 in. */ > #define VIRTIO_NET_F_GUEST_TSO6 8 /* Guest can handle TSOv6 in. */Is this a guest or a host checksum? We should differenciate between the two.> @@ -101,6 +102,7 @@ struct virtio_net_config { > struct virtio_net_hdr_v1 { > #define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 /* Use csum_start, csum_offset */ > #define VIRTIO_NET_HDR_F_DATA_VALID 2 /* Csum is valid */ > +#define VIRTIO_NET_HDR_F_CSUM_NOT_INET 4 /* Checksum is not inet */ > __u8 flags; > #define VIRTIO_NET_HDR_GSO_NONE 0 /* Not a GSO frame */ > #define VIRTIO_NET_HDR_GSO_TCPV4 1 /* GSO frame, IPv4 TCP (TSO) */ > -- > 2.9.5
Vlad Yasevich
2018-Apr-16 13:45 UTC
[PATCH net-next 1/5] virtio: Add support for SCTP checksum offloading
On 04/11/2018 06:49 PM, Michael S. Tsirkin wrote:> On Mon, Apr 02, 2018 at 09:40:02AM -0400, Vladislav Yasevich wrote: >> To support SCTP checksum offloading, we need to add a new feature >> to virtio_net, so we can negotiate support between the hypervisor >> and the guest. >> >> The signalling to the guest that an alternate checksum needs to >> be used is done via a new flag in the virtio_net_hdr. If the >> flag is set, the host will know to perform an alternate checksum >> calculation, which right now is only CRC32c. >> >> Signed-off-by: Vladislav Yasevich <vyasevic at redhat.com> >> --- >> drivers/net/virtio_net.c | 11 ++++++++--- >> include/linux/virtio_net.h | 6 ++++++ >> include/uapi/linux/virtio_net.h | 2 ++ >> 3 files changed, 16 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c >> index 7b187ec..b601294 100644 >> --- a/drivers/net/virtio_net.c >> +++ b/drivers/net/virtio_net.c >> @@ -2724,9 +2724,14 @@ static int virtnet_probe(struct virtio_device *vdev) >> /* Do we support "hardware" checksums? */ >> if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) { >> /* This opens up the world of extra features. */ >> - dev->hw_features |= NETIF_F_HW_CSUM | NETIF_F_SG; >> + netdev_features_t sctp = 0; >> + >> + if (virtio_has_feature(vdev, VIRTIO_NET_F_SCTP_CSUM)) >> + sctp |= NETIF_F_SCTP_CRC; >> + >> + dev->hw_features |= NETIF_F_HW_CSUM | NETIF_F_SG | sctp; >> if (csum) >> - dev->features |= NETIF_F_HW_CSUM | NETIF_F_SG; >> + dev->features |= NETIF_F_HW_CSUM | NETIF_F_SG | sctp; >> >> if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) { >> dev->hw_features |= NETIF_F_TSO >> @@ -2952,7 +2957,7 @@ static struct virtio_device_id id_table[] = { >> }; >> >> #define VIRTNET_FEATURES \ >> - VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM, \ >> + VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM, VIRTIO_NET_F_SCTP_CSUM, \ >> VIRTIO_NET_F_MAC, \ >> VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6, \ >> VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6, \ >> diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h >> index f144216..2e7a64a 100644 >> --- a/include/linux/virtio_net.h >> +++ b/include/linux/virtio_net.h >> @@ -39,6 +39,9 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb, >> >> if (!skb_partial_csum_set(skb, start, off)) >> return -EINVAL; >> + >> + if (hdr->flags & VIRTIO_NET_HDR_F_CSUM_NOT_INET) >> + skb->csum_not_inet = 1; >> } >> >> if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { >> @@ -96,6 +99,9 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, >> hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID; >> } /* else everything is zero */ >> >> + if (skb->csum_not_inet) >> + hdr->flags &= VIRTIO_NET_HDR_F_CSUM_NOT_INET; >> + >> return 0; >> } >> >> diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h >> index 5de6ed3..3f279c8 100644 >> --- a/include/uapi/linux/virtio_net.h >> +++ b/include/uapi/linux/virtio_net.h >> @@ -36,6 +36,7 @@ >> #define VIRTIO_NET_F_GUEST_CSUM 1 /* Guest handles pkts w/ partial csum */ >> #define VIRTIO_NET_F_CTRL_GUEST_OFFLOADS 2 /* Dynamic offload configuration. */ >> #define VIRTIO_NET_F_MTU 3 /* Initial MTU advice */ >> +#define VIRTIO_NET_F_SCTP_CSUM 4 /* SCTP checksum offload support */ >> #define VIRTIO_NET_F_MAC 5 /* Host has given MAC address. */ >> #define VIRTIO_NET_F_GUEST_TSO4 7 /* Guest can handle TSOv4 in. */ >> #define VIRTIO_NET_F_GUEST_TSO6 8 /* Guest can handle TSOv6 in. */ > > Is this a guest or a host checksum? We should differenciate between the > two.I suppose this is HOST checksum, since it behaves like VIRTIO_NET_F_CSUM only for SCTP. I couldn't find the use for the GUEST side flag, since there technically isn't any validations and there is no additional mappings from VIRTIO flag to a NETIF flag. If the feature is negotiated, the guest ends up generating partially check-summed packets, and the host turns on appropriate flags on it's side. The host will also make sure the checksum if fixed up if the guest doesn't support it. So 1 flag is currently all that is needed. -vlad> > >> @@ -101,6 +102,7 @@ struct virtio_net_config { >> struct virtio_net_hdr_v1 { >> #define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 /* Use csum_start, csum_offset */ >> #define VIRTIO_NET_HDR_F_DATA_VALID 2 /* Csum is valid */ >> +#define VIRTIO_NET_HDR_F_CSUM_NOT_INET 4 /* Checksum is not inet */ >> __u8 flags; >> #define VIRTIO_NET_HDR_GSO_NONE 0 /* Not a GSO frame */ >> #define VIRTIO_NET_HDR_GSO_TCPV4 1 /* GSO frame, IPv4 TCP (TSO) */ >> -- >> 2.9.5
Michael S. Tsirkin
2018-Apr-16 15:52 UTC
[PATCH net-next 1/5] virtio: Add support for SCTP checksum offloading
On Mon, Apr 16, 2018 at 09:45:48AM -0400, Vlad Yasevich wrote:> On 04/11/2018 06:49 PM, Michael S. Tsirkin wrote: > > On Mon, Apr 02, 2018 at 09:40:02AM -0400, Vladislav Yasevich wrote: > >> To support SCTP checksum offloading, we need to add a new feature > >> to virtio_net, so we can negotiate support between the hypervisor > >> and the guest. > >> > >> The signalling to the guest that an alternate checksum needs to > >> be used is done via a new flag in the virtio_net_hdr. If the > >> flag is set, the host will know to perform an alternate checksum > >> calculation, which right now is only CRC32c. > >> > >> Signed-off-by: Vladislav Yasevich <vyasevic at redhat.com> > >> --- > >> drivers/net/virtio_net.c | 11 ++++++++--- > >> include/linux/virtio_net.h | 6 ++++++ > >> include/uapi/linux/virtio_net.h | 2 ++Could you pls include a virtio TC mailing list on uapi changes?> >> 3 files changed, 16 insertions(+), 3 deletions(-) > >> > >> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > >> index 7b187ec..b601294 100644 > >> --- a/drivers/net/virtio_net.c > >> +++ b/drivers/net/virtio_net.c > >> @@ -2724,9 +2724,14 @@ static int virtnet_probe(struct virtio_device *vdev) > >> /* Do we support "hardware" checksums? */ > >> if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) { > >> /* This opens up the world of extra features. */ > >> - dev->hw_features |= NETIF_F_HW_CSUM | NETIF_F_SG; > >> + netdev_features_t sctp = 0; > >> + > >> + if (virtio_has_feature(vdev, VIRTIO_NET_F_SCTP_CSUM)) > >> + sctp |= NETIF_F_SCTP_CRC; > >> + > >> + dev->hw_features |= NETIF_F_HW_CSUM | NETIF_F_SG | sctp; > >> if (csum) > >> - dev->features |= NETIF_F_HW_CSUM | NETIF_F_SG; > >> + dev->features |= NETIF_F_HW_CSUM | NETIF_F_SG | sctp; > >> > >> if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) { > >> dev->hw_features |= NETIF_F_TSO > >> @@ -2952,7 +2957,7 @@ static struct virtio_device_id id_table[] = { > >> }; > >> > >> #define VIRTNET_FEATURES \ > >> - VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM, \ > >> + VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM, VIRTIO_NET_F_SCTP_CSUM, \ > >> VIRTIO_NET_F_MAC, \ > >> VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6, \ > >> VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6, \ > >> diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h > >> index f144216..2e7a64a 100644 > >> --- a/include/linux/virtio_net.h > >> +++ b/include/linux/virtio_net.h > >> @@ -39,6 +39,9 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb, > >> > >> if (!skb_partial_csum_set(skb, start, off)) > >> return -EINVAL; > >> + > >> + if (hdr->flags & VIRTIO_NET_HDR_F_CSUM_NOT_INET) > >> + skb->csum_not_inet = 1; > >> } > >> > >> if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { > >> @@ -96,6 +99,9 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, > >> hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID; > >> } /* else everything is zero */ > >> > >> + if (skb->csum_not_inet) > >> + hdr->flags &= VIRTIO_NET_HDR_F_CSUM_NOT_INET; > >> + > >> return 0; > >> } > >> > >> diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h > >> index 5de6ed3..3f279c8 100644 > >> --- a/include/uapi/linux/virtio_net.h > >> +++ b/include/uapi/linux/virtio_net.h > >> @@ -36,6 +36,7 @@ > >> #define VIRTIO_NET_F_GUEST_CSUM 1 /* Guest handles pkts w/ partial csum */ > >> #define VIRTIO_NET_F_CTRL_GUEST_OFFLOADS 2 /* Dynamic offload configuration. */ > >> #define VIRTIO_NET_F_MTU 3 /* Initial MTU advice */ > >> +#define VIRTIO_NET_F_SCTP_CSUM 4 /* SCTP checksum offload support */ > >> #define VIRTIO_NET_F_MAC 5 /* Host has given MAC address. */ > >> #define VIRTIO_NET_F_GUEST_TSO4 7 /* Guest can handle TSOv4 in. */ > >> #define VIRTIO_NET_F_GUEST_TSO6 8 /* Guest can handle TSOv6 in. */ > > > > Is this a guest or a host checksum? We should differenciate between the > > two. > > I suppose this is HOST checksum, since it behaves like VIRTIO_NET_F_CSUM only for > SCTP. I couldn't find the use for the GUEST side flag, since there technically > isn't any validations and there is no additional mappings from VIRTIO flag to a > NETIF flag. > > If the feature is negotiated, the guest ends up generating partially check-summed > packets, and the host turns on appropriate flags on it's side. The host will > also make sure the checksum if fixed up if the guest doesn't support it. > So 1 flag is currently all that is needed. > > -vladFine, but let's include HOST in there to make things clear. Also I think we should use a high flag, like 62.> > > > > >> @@ -101,6 +102,7 @@ struct virtio_net_config { > >> struct virtio_net_hdr_v1 { > >> #define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 /* Use csum_start, csum_offset */ > >> #define VIRTIO_NET_HDR_F_DATA_VALID 2 /* Csum is valid */ > >> +#define VIRTIO_NET_HDR_F_CSUM_NOT_INET 4 /* Checksum is not inet */ > >> __u8 flags; > >> #define VIRTIO_NET_HDR_GSO_NONE 0 /* Not a GSO frame */ > >> #define VIRTIO_NET_HDR_GSO_TCPV4 1 /* GSO frame, IPv4 TCP (TSO) */> >> -- > >> 2.9.5
Michael S. Tsirkin
2018-Apr-16 17:09 UTC
[PATCH net-next 1/5] virtio: Add support for SCTP checksum offloading
On Mon, Apr 16, 2018 at 09:45:48AM -0400, Vlad Yasevich wrote:> On 04/11/2018 06:49 PM, Michael S. Tsirkin wrote: > > On Mon, Apr 02, 2018 at 09:40:02AM -0400, Vladislav Yasevich wrote: > >> To support SCTP checksum offloading, we need to add a new feature > >> to virtio_net, so we can negotiate support between the hypervisor > >> and the guest. > >> > >> The signalling to the guest that an alternate checksum needs to > >> be used is done via a new flag in the virtio_net_hdr. If the > >> flag is set, the host will know to perform an alternate checksum > >> calculation, which right now is only CRC32c. > >> > >> Signed-off-by: Vladislav Yasevich <vyasevic at redhat.com> > >> --- > >> drivers/net/virtio_net.c | 11 ++++++++--- > >> include/linux/virtio_net.h | 6 ++++++ > >> include/uapi/linux/virtio_net.h | 2 ++ > >> 3 files changed, 16 insertions(+), 3 deletions(-) > >> > >> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > >> index 7b187ec..b601294 100644 > >> --- a/drivers/net/virtio_net.c > >> +++ b/drivers/net/virtio_net.c > >> @@ -2724,9 +2724,14 @@ static int virtnet_probe(struct virtio_device *vdev) > >> /* Do we support "hardware" checksums? */ > >> if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) { > >> /* This opens up the world of extra features. */ > >> - dev->hw_features |= NETIF_F_HW_CSUM | NETIF_F_SG; > >> + netdev_features_t sctp = 0; > >> + > >> + if (virtio_has_feature(vdev, VIRTIO_NET_F_SCTP_CSUM)) > >> + sctp |= NETIF_F_SCTP_CRC; > >> + > >> + dev->hw_features |= NETIF_F_HW_CSUM | NETIF_F_SG | sctp; > >> if (csum) > >> - dev->features |= NETIF_F_HW_CSUM | NETIF_F_SG; > >> + dev->features |= NETIF_F_HW_CSUM | NETIF_F_SG | sctp; > >> > >> if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) { > >> dev->hw_features |= NETIF_F_TSO > >> @@ -2952,7 +2957,7 @@ static struct virtio_device_id id_table[] = { > >> }; > >> > >> #define VIRTNET_FEATURES \ > >> - VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM, \ > >> + VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM, VIRTIO_NET_F_SCTP_CSUM, \ > >> VIRTIO_NET_F_MAC, \ > >> VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6, \ > >> VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6, \ > >> diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h > >> index f144216..2e7a64a 100644 > >> --- a/include/linux/virtio_net.h > >> +++ b/include/linux/virtio_net.h > >> @@ -39,6 +39,9 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb, > >> > >> if (!skb_partial_csum_set(skb, start, off)) > >> return -EINVAL; > >> + > >> + if (hdr->flags & VIRTIO_NET_HDR_F_CSUM_NOT_INET) > >> + skb->csum_not_inet = 1; > >> } > >> > >> if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { > >> @@ -96,6 +99,9 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, > >> hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID; > >> } /* else everything is zero */ > >> > >> + if (skb->csum_not_inet) > >> + hdr->flags &= VIRTIO_NET_HDR_F_CSUM_NOT_INET; > >> + > >> return 0; > >> } > >> > >> diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h > >> index 5de6ed3..3f279c8 100644 > >> --- a/include/uapi/linux/virtio_net.h > >> +++ b/include/uapi/linux/virtio_net.h > >> @@ -36,6 +36,7 @@ > >> #define VIRTIO_NET_F_GUEST_CSUM 1 /* Guest handles pkts w/ partial csum */ > >> #define VIRTIO_NET_F_CTRL_GUEST_OFFLOADS 2 /* Dynamic offload configuration. */ > >> #define VIRTIO_NET_F_MTU 3 /* Initial MTU advice */ > >> +#define VIRTIO_NET_F_SCTP_CSUM 4 /* SCTP checksum offload support */ > >> #define VIRTIO_NET_F_MAC 5 /* Host has given MAC address. */ > >> #define VIRTIO_NET_F_GUEST_TSO4 7 /* Guest can handle TSOv4 in. */ > >> #define VIRTIO_NET_F_GUEST_TSO6 8 /* Guest can handle TSOv6 in. */ > > > > Is this a guest or a host checksum? We should differenciate between the > > two. > > I suppose this is HOST checksum, since it behaves like VIRTIO_NET_F_CSUM only for > SCTP. I couldn't find the use for the GUEST side flag, since there technically > isn't any validations and there is no additional mappings from VIRTIO flag to a > NETIF flag. > > If the feature is negotiated, the guest ends up generating partially check-summed > packets, and the host turns on appropriate flags on it's side. The host will > also make sure the checksum if fixed up if the guest doesn't support it. > So 1 flag is currently all that is needed. > > -vladI see code handling VIRTIO_NET_HDR_F_CSUM_NOT_INET on RX side. Host needs to know whether it's ok/worth it to set this flag, too.> > > > > >> @@ -101,6 +102,7 @@ struct virtio_net_config { > >> struct virtio_net_hdr_v1 { > >> #define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 /* Use csum_start, csum_offset */ > >> #define VIRTIO_NET_HDR_F_DATA_VALID 2 /* Csum is valid */ > >> +#define VIRTIO_NET_HDR_F_CSUM_NOT_INET 4 /* Checksum is not inet */ > >> __u8 flags; > >> #define VIRTIO_NET_HDR_GSO_NONE 0 /* Not a GSO frame */ > >> #define VIRTIO_NET_HDR_GSO_TCPV4 1 /* GSO frame, IPv4 TCP (TSO) */ > >> -- > >> 2.9.5