[PATCH 00/22] x86: Enhance MTRR functionality to support multiple CPUs

Simon Glass sjg at chromium.org
Fri May 22 15:42:08 CEST 2020

Hi Andy,

On Fri, 22 May 2020 at 04:55, Andy Shevchenko
<andriy.shevchenko at linux.intel.com> wrote:
> On Thu, May 21, 2020 at 08:23:04PM -0600, Simon Glass wrote:
> > At present MTRRs are mirrored to the secondary CPUs only once, as those
> > CPUs are started up. But U-Boot may add more MTRRs later, e.g. if it
> > decides that a video console must be set up.
> >
> > This series enhances the x86 multi-processor support to allow MTRRs to
> > be updated at any time. It also updates the 'mtrr' command to support
> > setting the MTRRs on CPUs other than the boot CPU.
> Hmm... Why do you need MTRR if CPU supports PAT?

I suspect U-Boot could move to PAT one day but the needs are small in firmware.


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