arch/riscv: SV48 patch series questions

Leyfoon Tan leyfoon.tan at starfivetech.com
Thu Jun 30 19:34:08 PDT 2022



> -----Original Message-----
> From: Leyfoon Tan
> Sent: Thursday, 2 June, 2022 1:44 PM
> To: 'Palmer Dabbelt' <palmer at dabbelt.com>
> Cc: alexandre.ghiti at canonical.com; linux-riscv at lists.infradead.org; linux-
> kernel at vger.kernel.org
> Subject: RE: arch/riscv: SV48 patch series questions
> 
> 
> 
> > -----Original Message-----
> > From: Palmer Dabbelt <palmer at dabbelt.com>
> > Sent: Thursday, 2 June, 2022 11:44 AM
> > To: Leyfoon Tan <leyfoon.tan at starfivetech.com>
> > Cc: alexandre.ghiti at canonical.com; linux-riscv at lists.infradead.org;
> > linux- kernel at vger.kernel.org
> > Subject: Re: arch/riscv: SV48 patch series questions
> >
> > On Fri, 27 May 2022 02:37:34 PDT (-0700), leyfoon.tan at starfivetech.com
> > wrote:
> > > Hi Palmer
> > >
> > > Alex's "Introduce sv48 support without relocatable kernel" patch
> > > series in
> > [1] was partially merged to Linux v5.17. But there are 4 patches are
> > not merged (Patch-10 to 13).
> > >
> > > May I know what is the plan for these patches? Will them merged to
> > > next
> > v5.19 merging window? Or do you expect any changes for these patches
> > or Alex needs resend with rebase to latest kernel version?
> >
> > I just saw this as I was digging up Alex's old email to reply to, all
> > but #13 are now on for-next.
> >
> > > Note, we would like to use the Patch-13 in this series.
> >
> > Is your use case a CPU errata?  If so I think we should just go ahead
> > and add that errata via the existing errata mechanism.  If you've got
> > some other use case, do you mind elaborating?  From that other thread
> > it sounds like a command-line argument is the way to go for folks who
> > want to turn this off more dynamically, but happy to hear if you've
> > got something different in mind.
> It is not CPU errata.
> RISC-V cpu can have sv39, sv48 or even sv57. If it is a heterogenous system,
> cpu cores in the system might have different sv. Eg: one cpu can be sv39 and
> another core is sv48.
> In this case, auto detection is not work. So, Patch-13 can help in this use case.
> 
> >
Hi Palmer

Any further comment for this?

Any chance merging Patch-13 in [1]?

[1] https://patchwork.kernel.org/project/linux-riscv/patch/20211206104657.433304-14-alexandre.ghiti@canonical.com/

Regards
Ley Foon



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