On Wed, Dec 11, 2024 at 5:35 AM Dumitru Ceara <dce...@redhat.com> wrote:
>
> On 12/10/24 12:35 PM, Ales Musil wrote:
> > On Mon, Nov 11, 2024 at 11:43 AM Dumitru Ceara <dce...@redhat.com>
wrote:
> >
> >> The actions that retrieve the original tuple destination IPs and ports
> >> were used in the following way in ovn-northd:
> >>
> >> REG_ORIG_DIP_IPV4 " = ct_nw_dst()
> >> REG_ORIG_DIP_IPV6 " = ct_ip6_dst()
> >> REG_ORIG_TP_DPORT " = ct_tp_dst()
> >>
> >> Where:
> >> REG_ORIG_DIP_IPV4 is reg1
> >> REG_ORIG_DIP_IPV6 is xxreg1
> >> REG_ORIG_TP_DPORT is reg2[0..15]
> >>
> >> While the actions use a different intermediate register:
> >> ct_nw_dst() was reg4<-0; reg4<-ct_nw_dst
> >> ct_ip6_dst() was xxreg0<-0; xxreg0<-ct_ip6_dst
> >> ct_tp_dst() was reg8[0..15]<-0; reg8[0..15]<-ct_tp_dst
> >>
> >> We can reduce the set of registers we use in the OVN pipeline by
> >> changing the action definition to use the same registers ovn-northd
uses
> >> as final destination for the ct_*_dst() values. This will generate the
> >> following openflow rules:
> >>
> >> REG_ORIG_DIP_IPV4 " = ct_nw_dst()
> >> reg1<-0; reg1<-ct_nw_dst; reg1<-reg1
> >> REG_ORIG_DIP_IPV6 " = ct_ip6_dst()
> >> xxreg1<-0; xxreg1<-ct_ip6_dst; xxreg1<-xxreg1
> >> REG_ORIG_TP_DPORT " = ct_tp_dst()
> >> reg2[0..15]<-0; reg2[0..15]<-ct_tp_dst; reg2[0..15]<-reg2[0..15]
> >>
> >> As Ilya Maximets points out, overlapping source and destination are
> >> well defined for move actions:
> >>
> >>
https://opennetworking.org/wp-content/uploads/2014/10/openflow-switch-v1.5.0.noipr.pdf
> >>
> >> This action must behaves properly when src_oxm_id overlaps with
> >> dst_oxm_id, that is, it behaves as if src_oxm_id were copied out
> >> to a temporary buffer, then the temporary buffer copied to
> >> dst_oxm_id, if this is not possible the switch must reject the
> >> Copy Field action with a Bad Set Type error message.
> >>
> >> OpenvSwitch doesn't reject such actions.
> >>
> >> Fixes: 0f806cf08c36 ("Fix load balanced hairpin traffic for fragmented
> >> packets.")
> >> Signed-off-by: Dumitru Ceara <dce...@redhat.com>
> >> ---
> >> include/ovn/logical-fields.h | 7 ++++---
> >> tests/ovn.at | 8 ++++----
> >> 2 files changed, 8 insertions(+), 7 deletions(-)
> >>
> >> diff --git a/include/ovn/logical-fields.h
b/include/ovn/logical-fields.h
> >> index d563e044cb..70c6b93c41 100644
> >> --- a/include/ovn/logical-fields.h
> >> +++ b/include/ovn/logical-fields.h
> >> @@ -60,9 +60,10 @@ enum ovn_controller_event {
> >> #define MFF_LOG_LB_AFF_MATCH_LR_IP6_ADDR MFF_XXREG1
> >> #define MFF_LOG_LB_AFF_MATCH_PORT MFF_REG8
> >>
> >> -#define MFF_LOG_CT_ORIG_NW_DST_ADDR MFF_REG4
> >> -#define MFF_LOG_CT_ORIG_IP6_DST_ADDR MFF_XXREG0
> >> -#define MFF_LOG_CT_ORIG_TP_DST_PORT MFF_REG8
> >> +#define MFF_LOG_CT_ORIG_NW_DST_ADDR MFF_REG1 /*
> >> REG_ORIG_DIP_IPV4 */
> >> +#define MFF_LOG_CT_ORIG_IP6_DST_ADDR MFF_XXREG1 /*
> >> REG_ORIG_DIP_IPV6 */
> >> +#define MFF_LOG_CT_ORIG_TP_DST_PORT MFF_REG2 /*
> >> REG_ORIG_TP_DPORT
> >> + * (bits
0..15). */
> >>
> >> void ovn_init_symtab(struct shash *symtab);
> >>
> >> diff --git a/tests/ovn.at b/tests/ovn.at
> >> index 15b78f4c37..03fd2090fc 100644
> >> --- a/tests/ovn.at
> >> +++ b/tests/ovn.at
> >> @@ -2420,10 +2420,10 @@ mac_cache_use;
> >>
> >> # ct_nw_dst()
> >> reg1 = ct_nw_dst();
> >> - encodes as
> >>
set_field:0->reg4,resubmit(,OFTABLE_CT_ORIG_NW_DST_LOAD),move:NXM_NX_REG4[[]]->NXM_NX_XXREG0[[64..95]]
> >> + encodes as
> >>
set_field:0->reg1,resubmit(,OFTABLE_CT_ORIG_NW_DST_LOAD),move:NXM_NX_REG1[[]]->NXM_NX_XXREG0[[64..95]]
> >>
> >> xreg1[[3..34]] = ct_nw_dst();
> >> - encodes as
> >>
set_field:0->reg4,resubmit(,OFTABLE_CT_ORIG_NW_DST_LOAD),move:NXM_NX_REG4[[]]->NXM_NX_XXREG0[[3..34]]
> >> + encodes as
> >>
set_field:0->reg1,resubmit(,OFTABLE_CT_ORIG_NW_DST_LOAD),move:NXM_NX_REG1[[]]->NXM_NX_XXREG0[[3..34]]
> >>
> >> reg1[[3..34]] = ct_nw_dst();
> >> Cannot select bits 3 to 34 of 32-bit field reg1.
> >> @@ -2442,7 +2442,7 @@ ct_nw_dst();
> >>
> >> # ct_ip6_dst()
> >> xxreg1 = ct_ip6_dst();
> >> - encodes as
> >>
set_field:0/0xffffffffffffffff->xxreg0,set_field:0/0xffffffffffffffff0000000000000000->xxreg0,resubmit(,OFTABLE_CT_ORIG_IP6_DST_LOAD),move:NXM_NX_XXREG0[[]]->NXM_NX_XXREG1[[]]
> >> + encodes as
> >>
set_field:0/0xffffffffffffffff->xxreg1,set_field:0/0xffffffffffffffff0000000000000000->xxreg1,resubmit(,OFTABLE_CT_ORIG_IP6_DST_LOAD),move:NXM_NX_XXREG1[[]]->NXM_NX_XXREG1[[]]
> >>
> >> reg1 = ct_ip6_dst();
> >> Cannot use 32-bit field reg1[[0..31]] where 128-bit field is
required.
> >> @@ -2455,7 +2455,7 @@ ct_ip6_dst();
> >>
> >> # ct_tp_dst()
> >> reg1[[0..15]] = ct_tp_dst();
> >> - encodes as
> >>
set_field:0/0xffff->reg8,resubmit(,OFTABLE_CT_ORIG_TP_DST_LOAD),move:NXM_NX_REG8[[0..15]]->NXM_NX_XXREG0[[64..79]]
> >> + encodes as
> >>
set_field:0/0xffff->reg2,resubmit(,OFTABLE_CT_ORIG_TP_DST_LOAD),move:NXM_NX_REG2[[0..15]]->NXM_NX_XXREG0[[64..79]]
> >>
> >> reg1 = ct_tp_dst();
> >> Cannot use 32-bit field reg1[[0..31]] where 16-bit field is
required.
> >> --
> >> 2.46.2
> >>
> >> _______________________________________________
> >> dev mailing list
> >> d...@openvswitch.org
> >> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> >>
> >>
> > Looks good to me, thanks.
> >
> > Acked-by: Ales Musil <amu...@redhat.com>
> >
>
> Thanks, Ales! Applied to main and backported to 24.09 and 24.03.
>
> Regards,
> Dumitru
>
Hi Dumitru, Ales, I am trying to figure out the current register usage and
saw this old commit. I am not sure I understand the motivation of this
patch. Is there a problem of using different registers for intermediate
usage? Although this patch tried to use the same register for intermediate
and final destination, a later commit from Ales 91988089c5 ("northd:
Consolidate register usage in logical flows.") already broke it again.
Shall we fix that again?
Thanks,
Han
>
> _______________________________________________
> dev mailing list
> d...@openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
_______________________________________________
dev mailing list
d...@openvswitch.org
https://mail.openvswitch.org/mailman/listinfo/ovs-dev
