Re: [PATCH v19 7/7] ptp: arm/arm64: Enable ptp_kvm for arm/arm64

Marc Zyngier
2021-05-26T08:02:10Z

Hi Geert,

On Wed, 26 May 2021 08:52:42 +0100,
Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> Hi Marc,
>
> On Tue, May 11, 2021 at 11:13 AM Marc Zyngier <maz@kernel.org> wrote:
> > On 2021-05-11 10:07, Geert Uytterhoeven wrote:
> > > On Tue, Mar 30, 2021 at 4:56 PM Marc Zyngier <maz@kernel.org> wrote:
> > >> From: Jianyong Wu <jianyong.wu@arm.com>
> > >
> > >> --- a/drivers/ptp/Kconfig
> > >> +++ b/drivers/ptp/Kconfig
> > >> @@ -108,7 +108,7 @@ config PTP_1588_CLOCK_PCH
> > >> config PTP_1588_CLOCK_KVM
> > >> tristate "KVM virtual PTP clock"
> > >> depends on PTP_1588_CLOCK
> > >> - depends on KVM_GUEST && X86
> > >> + depends on (KVM_GUEST && X86) || (HAVE_ARM_SMCCC_DISCOVERY &&
> > >> ARM_ARCH_TIMER)
> > >
> > > Why does this not depend on KVM_GUEST on ARM?
> > > I.e. shouldn't the dependency be:
> > >
> > > KVM_GUEST && (X86 || (HAVE_ARM_SMCCC_DISCOVERY && ARM_ARCH_TIMER))
> > >
> > > ?
> >
> > arm/arm64 do not select KVM_GUEST. Any kernel can be used for a guest,
> > and KVM/arm64 doesn't know about this configuration symbol.
>
> OK.
>
> Does PTP_1588_CLOCK_KVM need to default to yes?
> Perhaps only on X86, to maintain the status quo?

I think I don't really understand the problem you are trying to
solve. Is it that 'make oldconfig' now asks you about this new driver?
Why is that an issue?

Thanks,

M.

--
Without deviation from the norm, progress is not possible.