RE: [PATCH v4 1/2] config: correct cpu instruction set for cross build

[Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>]

> -----Original Message-----
> From: Joyce Kong <Joyce.Kong@arm.com>
> Sent: Friday, December 8, 2023 8:21 AM
> To: Stephen Hemminger <stephen@networkplumber.org>
> Cc: thomas@monjalon.net; Ruifeng Wang <Ruifeng.Wang@arm.com>;
> bruce.richardson@intel.com; dev@dpdk.org; nd <nd@arm.com>;
> stable@dpdk.org
> Subject: [EXT] RE: [PATCH v4 1/2] config: correct cpu instruction set for cross
> build
> 
> External Email
> 
> ----------------------------------------------------------------------
> > -----Original Message-----
> > From: Stephen Hemminger <stephen@networkplumber.org>
> > Sent: Friday, December 8, 2023 6:41 AM
> > To: Joyce Kong <Joyce.Kong@arm.com>
> > Cc: thomas@monjalon.net; Ruifeng Wang <Ruifeng.Wang@arm.com>;
> > bruce.richardson@intel.com; dev@dpdk.org; nd <nd@arm.com>;
> > stable@dpdk.org
> > Subject: Re: [PATCH v4 1/2] config: correct cpu instruction set for cross
> build
> >
> > On Tue,  5 Dec 2023 03:52:58 +0000
> > Joyce Kong <joyce.kong@arm.com> wrote:
> >
> > > The platform value would be 'native' only when not cross build.
> > > Move the operation about modifying cpu_instruction_set while platform
> > > equals 'native' to the not cross build branch.
> > >
> > > Fixes: bf66003b51ec ("build: use platform for generic and native
> > > builds")
> > > Cc: stable@dpdk.org
> > >
> > > Signed-off-by: Joyce Kong <joyce.kong@arm.com>
> > > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> >
> > Looks right, what is the impact on existing users doing current cross builds?
> 
> The original operation changes cpu_instruction_set to 'native' when both
> 'platform == native' and 'cpu_instruction_set == auto'.
> There was no impact on the existing users for current cross build, as the cross
> files set cpu field to a specific arch, such as 'armv8-a', and this didn't trigger
> the modification for cpu_instruction_set.
> However, if we want to use a common arch in cross files like 'auto', the
> modification operation would override 'native' value to cpu_instruction_set
> and b7676fcccab4 ("config: verify machine arch flag") would break the build
> as it tries to test -march=native.
> 
> >
> > Acked-by: Stephen Hemminger <stephen@networkplumber.org>

Tested-by: Pavan Nikhilesh <pbhagavatula@marvell.com>