Re: [PATCH v1] net/axgbe: use CPUID to identify cpu

[David Marchand <david.marchand@redhat.com>]

On Fri, Sep 15, 2023 at 12:54 PM Ferruh Yigit <ferruh.yigit@amd.com> wrote:
>
> On 8/31/2023 1:31 PM, Selwin Sebastian wrote:
> > Using root complex to identify cpu will not work for vm passthrough.
> > CPUID is used to get family and modelid to identify cpu
> >
> > Fixes: b0db927b5eba ("net/axgbe: use PCI root complex device to distinguish device")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Selwin Sebastian <selwin.sebastian@amd.com>
> > ---
> >  drivers/net/axgbe/axgbe_ethdev.c | 102 ++++++++++++++++++-------------
> >  1 file changed, 59 insertions(+), 43 deletions(-)
> >
> > diff --git a/drivers/net/axgbe/axgbe_ethdev.c b/drivers/net/axgbe/axgbe_ethdev.c
> > index 48714eebe6..59f5d713d0 100644
> > --- a/drivers/net/axgbe/axgbe_ethdev.c
> > +++ b/drivers/net/axgbe/axgbe_ethdev.c
> > @@ -12,6 +12,8 @@
> >
> >  #include "eal_filesystem.h"
> >
> > +#include <cpuid.h>
> > +
> >
>
> This patch cause build errors for some non x86 architecture, because of
> 'cpuid.h'.
>
> There is already a 'rte_cpuid.h' file that includes 'cpuid.h' and it is
> x86 only file.
>
> @Selwin, does it makes sense to implement the feature you are trying to
> get in eal/x86 level and use that API in the driver?

This driver was expected to compile on all arches.
The meson.build seems to show an intention of compiling/working on non
x86 arch...

On the other hand (and if I understand correctly the runtime check),
it was never expected to work with anything but a AMD PCI root
complex.


>
>
> For those eal/x86 APIs, they will be missing in other architectures,
>
> @David which one is better, to implement APIs for other architectures
> but those just return error, or restrict driver build to x86?

We gain compilation coverage, but if the vendor itself refuses runtime
on anything but its platform... I don't think we should bother with
this.
Did I miss something?



-- 
David Marchand