[ovs-dev] [PATCH v2 10/21] lflow: Correct register definitions to use subfields for overlaps.

Ryan Moats rmoats at us.ibm.com
Mon Aug 8 17:12:53 UTC 2016


"dev" <dev-bounces at openvswitch.org> wrote on 08/08/2016 11:14:21 AM:

> From: Ben Pfaff <blp at ovn.org>
> To: dev at openvswitch.org
> Cc: Ben Pfaff <blp at ovn.org>
> Date: 08/08/2016 11:16 AM
> Subject: [ovs-dev] [PATCH v2 10/21] lflow: Correct register
> definitions to use subfields for overlaps.
> Sent by: "dev" <dev-bounces at openvswitch.org>
>
> OVN expressions need to know what fields overlap or alias one another.
> This is supposed to be done via subfields: if two fields overlap, then
the
> smaller one should be defined as a subfield of the larger one.  For
> example, reg0 should be defined as xxreg0[96..127].  The symbol table in
> lflow didn't do this, so it's possible for confusion to result.  (I don't
> have evidence of this actually happening, because it would only occur
> in a case where the same bits of a field were referred to with different
> names.)
>
> This commit fixes the problem.  It deserves a test, but that's somewhat
> difficult at this point, so it will actually happen in a future commit.
>
> Signed-off-by: Ben Pfaff <blp at ovn.org>
> ---

Yes, we do really need a test for this - add it to the pile of debt...

Acked-by: Ryan Moats <rmoats at us.ibm.com>



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