RE: [PATCH v2 1/3] eal: add x86 cpuid support for monitorx

["Tummala, Sivaprasad" <Sivaprasad.Tummala@amd.com>]

[AMD Official Use Only - General]

Hi David, 

> -----Original Message-----
> From: David Marchand <david.marchand@redhat.com>
> Sent: Thursday, April 13, 2023 5:30 PM
> To: Tummala, Sivaprasad <Sivaprasad.Tummala@amd.com>
> Cc: david.hunt@intel.com; dev@dpdk.org; Thomas Monjalon
> <thomas@monjalon.net>; Burakov, Anatoly <anatoly.burakov@intel.com>
> Subject: Re: [PATCH v2 1/3] eal: add x86 cpuid support for monitorx
> 
> Caution: This message originated from an External Source. Use proper caution
> when opening attachments, clicking links, or responding.
> 
> 
> On Thu, Apr 13, 2023 at 1:54 PM Sivaprasad Tummala
> <sivaprasad.tummala@amd.com> wrote:
> >
> > Add a new CPUID flag to indicate support for monitorx instruction on
> > AMD Epyc processors.
> >
> > Signed-off-by: Sivaprasad Tummala <sivaprasad.tummala@amd.com>
> > ---
> >  lib/eal/include/generic/rte_cpuflags.h | 2 ++
> >  lib/eal/x86/include/rte_cpuflags.h     | 1 +
> >  lib/eal/x86/rte_cpuflags.c             | 3 +++
> >  3 files changed, 6 insertions(+)
> >
> > diff --git a/lib/eal/include/generic/rte_cpuflags.h
> > b/lib/eal/include/generic/rte_cpuflags.h
> > index d35551e931..db653a8dd7 100644
> > --- a/lib/eal/include/generic/rte_cpuflags.h
> > +++ b/lib/eal/include/generic/rte_cpuflags.h
> > @@ -26,6 +26,8 @@ struct rte_cpu_intrinsics {
> >         /**< indicates support for rte_power_pause function */
> >         uint32_t power_monitor_multi : 1;
> >         /**< indicates support for rte_power_monitor_multi function */
> > +       uint32_t amd_power_monitorx : 1;
> > +       /**< indicates amd support for rte_power_monitor function */
> 
> I did not look at the patch detail, I just stopped at this part.
> What makes the AMD monitorx stuff special that it needs to be exposed in the
> generic API?

Monitorx is different ISA /opcode (0F 01 FA) as compared to UMonitor (0F 01 C8). This need to be distinguished 
on specific x86 platforms. Hence in the current power intrinsics, for x86 we require a new flag to 
distinguish MonitorX and UMonitor and invoke the appropriate x86 ISA in the datapath.

Thanks & Regards,
Sivaprasad