Re: [PATCH net-next 1/5] virtio: Add support for SCTP checksum offloading
On 04/16/2018 01:09 PM, Michael S. Tsirkin wrote:
> 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
---
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
>
> I 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.
I think I understand. I have to r
Re: [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
> >> ---
> >> 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
I 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
Re: [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
> ---
> 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) {
Looks like we need a feature flag to tell host guest is able to handle this flag
in incoming packets ...
> @@ -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 */
Is comment above still correct?
>
> + if (skb->csum_not_inet)
> + hdr->flags &= VIRTIO_NET_HDR_F_CSUM_NOT_INET;
> +
... and a separate flag to tell guest it's ok to set this flag in
outgoing packets.
Also - this chunk looks like a hack fixing up a value we
have set incorrectly.
Specifically this clears all flags except VIRTIO_NET_HDR_F_CSUM_NOT_INET.
Why do this at all? Do we really want to clear e.g. NEEDS_CSUM? I think we do
not
since csum_start, csum_offset are set.
Also - what will ever set this flag in the header?
> 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. */
> @@ -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 */
Not very informative. Instead, please specify what is it actually.
> __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
___
Virtualiz
Re: [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
> >> ---
> >> 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.
>
> -vlad
Fine, 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 {
>
Re: [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
>> ---
>> 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_MTU3 /* Initial MTU advice */
>> +#define VIRTIO_NET_F_SCTP_CSUM 4 /* SCTP checksum offload support */
>> #define VIRTIO_NET_F_MAC5 /* 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_TCPV
Re: [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
> ---
> 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
___
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Re: [PATCH net-next 1/5] virtio: Add support for SCTP checksum offloading
On 2018年04月02日 21:40, 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
---
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, \
It looks to me _F_SCTP_CSUM implies the ability of both device and
driver. Do we still need the flexibility like csum to differ guest/host
ability like e.g _F_GUEST_SCTP_CSUM?
Thanks
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. */
@@ -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) */
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