diff mbox series

[v2] net/virtio: handle Tx checksums correctly for tunnel packets

Message ID 20210916184955.2755-1-ivan.malov@oktetlabs.ru (mailing list archive)
State New
Delegated to: Maxime Coquelin
Headers show
Series [v2] net/virtio: handle Tx checksums correctly for tunnel packets | expand

Checks

Context Check Description
ci/iol-x86_64-compile-testing success Testing PASS
ci/iol-aarch64-compile-testing success Testing PASS
ci/iol-x86_64-unit-testing success Testing PASS
ci/iol-intel-Functional success Functional Testing PASS
ci/intel-Testing fail Testing issues
ci/Intel-compilation success Compilation OK
ci/github-robot: build success github build: passed
ci/checkpatch success coding style OK

Commit Message

Ivan Malov Sept. 16, 2021, 6:49 p.m. UTC
Tx prepare method calls rte_net_intel_cksum_prepare(), which
handles tunnel packets correctly, but Tx burst path does not
take tunnel presence into account when computing the offsets.

Fixes: 58169a9c8153 ("net/virtio: support Tx checksum offload")
Cc: stable@dpdk.org

Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
---
 drivers/net/virtio/virtqueue.h | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

Comments

Andrew Rybchenko Oct. 14, 2021, 6:45 a.m. UTC | #1
Hi Maxime, Chenbo,

is the any problem with the patch below?

Thanks,
Andrew.

On 9/16/21 9:49 PM, Ivan Malov wrote:
> Tx prepare method calls rte_net_intel_cksum_prepare(), which
> handles tunnel packets correctly, but Tx burst path does not
> take tunnel presence into account when computing the offsets.
> 
> Fixes: 58169a9c8153 ("net/virtio: support Tx checksum offload")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
> Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> ---
>  drivers/net/virtio/virtqueue.h | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
> index 03957b2bd0..b83ff32efb 100644
> --- a/drivers/net/virtio/virtqueue.h
> +++ b/drivers/net/virtio/virtqueue.h
> @@ -620,19 +620,21 @@ static inline void
>  virtqueue_xmit_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *cookie)
>  {
>  	uint64_t csum_l4 = cookie->ol_flags & PKT_TX_L4_MASK;
> +	uint16_t o_l23_len = (cookie->ol_flags & PKT_TX_TUNNEL_MASK) ?
> +			     cookie->outer_l2_len + cookie->outer_l3_len : 0;
>  
>  	if (cookie->ol_flags & PKT_TX_TCP_SEG)
>  		csum_l4 |= PKT_TX_TCP_CKSUM;
>  
>  	switch (csum_l4) {
>  	case PKT_TX_UDP_CKSUM:
> -		hdr->csum_start = cookie->l2_len + cookie->l3_len;
> +		hdr->csum_start = o_l23_len + cookie->l2_len + cookie->l3_len;
>  		hdr->csum_offset = offsetof(struct rte_udp_hdr, dgram_cksum);
>  		hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
>  		break;
>  
>  	case PKT_TX_TCP_CKSUM:
> -		hdr->csum_start = cookie->l2_len + cookie->l3_len;
> +		hdr->csum_start = o_l23_len + cookie->l2_len + cookie->l3_len;
>  		hdr->csum_offset = offsetof(struct rte_tcp_hdr, cksum);
>  		hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
>  		break;
> @@ -650,7 +652,8 @@ virtqueue_xmit_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *cookie)
>  			VIRTIO_NET_HDR_GSO_TCPV6 :
>  			VIRTIO_NET_HDR_GSO_TCPV4;
>  		hdr->gso_size = cookie->tso_segsz;
> -		hdr->hdr_len = cookie->l2_len + cookie->l3_len + cookie->l4_len;
> +		hdr->hdr_len = o_l23_len + cookie->l2_len + cookie->l3_len +
> +			       cookie->l4_len;
>  	} else {
>  		ASSIGN_UNLESS_EQUAL(hdr->gso_type, 0);
>  		ASSIGN_UNLESS_EQUAL(hdr->gso_size, 0);
>
Xia, Chenbo Oct. 14, 2021, 7:12 a.m. UTC | #2
> -----Original Message-----
> From: Ivan Malov <ivan.malov@oktetlabs.ru>
> Sent: Friday, September 17, 2021 2:50 AM
> To: dev@dpdk.org
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>; stable@dpdk.org; Andrew
> Rybchenko <andrew.rybchenko@oktetlabs.ru>; Xia, Chenbo <chenbo.xia@intel.com>;
> Yuanhan Liu <yuanhan.liu@linux.intel.com>; Olivier Matz
> <olivier.matz@6wind.com>
> Subject: [PATCH v2] net/virtio: handle Tx checksums correctly for tunnel
> packets
> 
> Tx prepare method calls rte_net_intel_cksum_prepare(), which
> handles tunnel packets correctly, but Tx burst path does not
> take tunnel presence into account when computing the offsets.
> 
> Fixes: 58169a9c8153 ("net/virtio: support Tx checksum offload")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
> Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> ---
>  drivers/net/virtio/virtqueue.h | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
> index 03957b2bd0..b83ff32efb 100644
> --- a/drivers/net/virtio/virtqueue.h
> +++ b/drivers/net/virtio/virtqueue.h
> @@ -620,19 +620,21 @@ static inline void
>  virtqueue_xmit_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *cookie)
>  {
>  	uint64_t csum_l4 = cookie->ol_flags & PKT_TX_L4_MASK;
> +	uint16_t o_l23_len = (cookie->ol_flags & PKT_TX_TUNNEL_MASK) ?
> +			     cookie->outer_l2_len + cookie->outer_l3_len : 0;
> 
>  	if (cookie->ol_flags & PKT_TX_TCP_SEG)
>  		csum_l4 |= PKT_TX_TCP_CKSUM;
> 
>  	switch (csum_l4) {
>  	case PKT_TX_UDP_CKSUM:
> -		hdr->csum_start = cookie->l2_len + cookie->l3_len;
> +		hdr->csum_start = o_l23_len + cookie->l2_len + cookie->l3_len;
>  		hdr->csum_offset = offsetof(struct rte_udp_hdr, dgram_cksum);
>  		hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
>  		break;
> 
>  	case PKT_TX_TCP_CKSUM:
> -		hdr->csum_start = cookie->l2_len + cookie->l3_len;
> +		hdr->csum_start = o_l23_len + cookie->l2_len + cookie->l3_len;
>  		hdr->csum_offset = offsetof(struct rte_tcp_hdr, cksum);
>  		hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
>  		break;
> @@ -650,7 +652,8 @@ virtqueue_xmit_offload(struct virtio_net_hdr *hdr, struct
> rte_mbuf *cookie)
>  			VIRTIO_NET_HDR_GSO_TCPV6 :
>  			VIRTIO_NET_HDR_GSO_TCPV4;
>  		hdr->gso_size = cookie->tso_segsz;
> -		hdr->hdr_len = cookie->l2_len + cookie->l3_len + cookie->l4_len;
> +		hdr->hdr_len = o_l23_len + cookie->l2_len + cookie->l3_len +
> +			       cookie->l4_len;
>  	} else {
>  		ASSIGN_UNLESS_EQUAL(hdr->gso_type, 0);
>  		ASSIGN_UNLESS_EQUAL(hdr->gso_size, 0);
> --
> 2.20.1

Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>
Olivier Matz Oct. 15, 2021, 8:32 a.m. UTC | #3
On Thu, Oct 14, 2021 at 07:12:29AM +0000, Xia, Chenbo wrote:
> > -----Original Message-----
> > From: Ivan Malov <ivan.malov@oktetlabs.ru>
> > Sent: Friday, September 17, 2021 2:50 AM
> > To: dev@dpdk.org
> > Cc: Maxime Coquelin <maxime.coquelin@redhat.com>; stable@dpdk.org; Andrew
> > Rybchenko <andrew.rybchenko@oktetlabs.ru>; Xia, Chenbo <chenbo.xia@intel.com>;
> > Yuanhan Liu <yuanhan.liu@linux.intel.com>; Olivier Matz
> > <olivier.matz@6wind.com>
> > Subject: [PATCH v2] net/virtio: handle Tx checksums correctly for tunnel
> > packets
> > 
> > Tx prepare method calls rte_net_intel_cksum_prepare(), which
> > handles tunnel packets correctly, but Tx burst path does not
> > take tunnel presence into account when computing the offsets.
> > 
> > Fixes: 58169a9c8153 ("net/virtio: support Tx checksum offload")
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
> > Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> > ---
> >  drivers/net/virtio/virtqueue.h | 9 ++++++---
> >  1 file changed, 6 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
> > index 03957b2bd0..b83ff32efb 100644
> > --- a/drivers/net/virtio/virtqueue.h
> > +++ b/drivers/net/virtio/virtqueue.h
> > @@ -620,19 +620,21 @@ static inline void
> >  virtqueue_xmit_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *cookie)
> >  {
> >  	uint64_t csum_l4 = cookie->ol_flags & PKT_TX_L4_MASK;
> > +	uint16_t o_l23_len = (cookie->ol_flags & PKT_TX_TUNNEL_MASK) ?
> > +			     cookie->outer_l2_len + cookie->outer_l3_len : 0;
> > 
> >  	if (cookie->ol_flags & PKT_TX_TCP_SEG)
> >  		csum_l4 |= PKT_TX_TCP_CKSUM;
> > 
> >  	switch (csum_l4) {
> >  	case PKT_TX_UDP_CKSUM:
> > -		hdr->csum_start = cookie->l2_len + cookie->l3_len;
> > +		hdr->csum_start = o_l23_len + cookie->l2_len + cookie->l3_len;
> >  		hdr->csum_offset = offsetof(struct rte_udp_hdr, dgram_cksum);
> >  		hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
> >  		break;
> > 
> >  	case PKT_TX_TCP_CKSUM:
> > -		hdr->csum_start = cookie->l2_len + cookie->l3_len;
> > +		hdr->csum_start = o_l23_len + cookie->l2_len + cookie->l3_len;
> >  		hdr->csum_offset = offsetof(struct rte_tcp_hdr, cksum);
> >  		hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
> >  		break;
> > @@ -650,7 +652,8 @@ virtqueue_xmit_offload(struct virtio_net_hdr *hdr, struct
> > rte_mbuf *cookie)
> >  			VIRTIO_NET_HDR_GSO_TCPV6 :
> >  			VIRTIO_NET_HDR_GSO_TCPV4;
> >  		hdr->gso_size = cookie->tso_segsz;
> > -		hdr->hdr_len = cookie->l2_len + cookie->l3_len + cookie->l4_len;
> > +		hdr->hdr_len = o_l23_len + cookie->l2_len + cookie->l3_len +
> > +			       cookie->l4_len;
> >  	} else {
> >  		ASSIGN_UNLESS_EQUAL(hdr->gso_type, 0);
> >  		ASSIGN_UNLESS_EQUAL(hdr->gso_size, 0);
> > --
> > 2.20.1
> 
> Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>
> 

I have one comment to mention that from application perspective, it has
to take care that the driver does not support outer tunnel offload (this
matches the advertised capabilities). For instance, in case of a vxlan
tunnel, if the outer checksum needs to be calculated, it has to be done
by the application. In short, the application can ask to offload the
inner part if no offload is required on the outer part.

Also, since grep "PKT_TX_TUNNEL" in driver/net/ixgbe gives nothing, it
seems the ixgbe driver does not support the same offload request than
described in this patch:
  (m->ol_flags & PKT_TX_TUNNEL_MASK) == PKT_TX_TUNNEL_XXXXX
  m->outer_l2_len = outer l2 length
  m->outer_l3_len = outer l3 length
  m->l2_len = outer l4 length + tunnel len + inner l2 len
  m->l3_len = inner l3 len
  m->l4_len = inner l4 len

An alternative for doing the same (that would work with ixgbe and
current virtio) is to give:
  (m->ol_flags & PKT_TX_TUNNEL_MASK) == 0
  m->l2_len = outer lengths + tunnel len + inner l2 len
  m->l3_len = inner l3 len
  m->l4_len = inner l4 len

I think a capability may be missing to differentiate which drivers
support which mode. Or, all drivers could be fixed to support both modes
(and this would make this patch valid).

Thanks,
Olivier
diff mbox series

Patch

diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
index 03957b2bd0..b83ff32efb 100644
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -620,19 +620,21 @@  static inline void
 virtqueue_xmit_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *cookie)
 {
 	uint64_t csum_l4 = cookie->ol_flags & PKT_TX_L4_MASK;
+	uint16_t o_l23_len = (cookie->ol_flags & PKT_TX_TUNNEL_MASK) ?
+			     cookie->outer_l2_len + cookie->outer_l3_len : 0;
 
 	if (cookie->ol_flags & PKT_TX_TCP_SEG)
 		csum_l4 |= PKT_TX_TCP_CKSUM;
 
 	switch (csum_l4) {
 	case PKT_TX_UDP_CKSUM:
-		hdr->csum_start = cookie->l2_len + cookie->l3_len;
+		hdr->csum_start = o_l23_len + cookie->l2_len + cookie->l3_len;
 		hdr->csum_offset = offsetof(struct rte_udp_hdr, dgram_cksum);
 		hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 		break;
 
 	case PKT_TX_TCP_CKSUM:
-		hdr->csum_start = cookie->l2_len + cookie->l3_len;
+		hdr->csum_start = o_l23_len + cookie->l2_len + cookie->l3_len;
 		hdr->csum_offset = offsetof(struct rte_tcp_hdr, cksum);
 		hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 		break;
@@ -650,7 +652,8 @@  virtqueue_xmit_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *cookie)
 			VIRTIO_NET_HDR_GSO_TCPV6 :
 			VIRTIO_NET_HDR_GSO_TCPV4;
 		hdr->gso_size = cookie->tso_segsz;
-		hdr->hdr_len = cookie->l2_len + cookie->l3_len + cookie->l4_len;
+		hdr->hdr_len = o_l23_len + cookie->l2_len + cookie->l3_len +
+			       cookie->l4_len;
 	} else {
 		ASSIGN_UNLESS_EQUAL(hdr->gso_type, 0);
 		ASSIGN_UNLESS_EQUAL(hdr->gso_size, 0);