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From: Catalin Marinas <catalin.marinas@arm.com>
To: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	marc.w.gonzalez@free.fr,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Dave Martin <Dave.Martin@arm.com>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: Unexpected variation in SYS_ID_AA64MMFR0_EL1
Date: Mon, 3 Dec 2018 15:32:32 +0000	[thread overview]
Message-ID: <20181203153232.no5yiliofqtfelfu@localhost> (raw)
In-Reply-To: <44c18e70-e4d9-5e4d-1326-aa1f88a16315@arm.com>

On Fri, Nov 30, 2018 at 01:23:28PM +0000, Suzuki K. Poulose wrote:
> On 30/11/2018 13:12, Ard Biesheuvel wrote:
> > On Fri, 30 Nov 2018 at 13:15, Marc Gonzalez <marc.w.gonzalez@free.fr> wrote:
> > > On an APQ8098-based system, for cores 4-7 (little cores?), the kernel prints:
> > > 
> > > [    0.179055] CPU features: SANITY CHECK: Unexpected variation in SYS_ID_AA64MMFR0_EL1.
> > > Boot CPU: 0x00000000001122, CPU4: 0x00000000101122
> > > 
> > > TGran16, [23:20]
> > >      Support for 16KB memory translation granule size:
> > >          0x1     Indicates that the 16KB granule is supported.
> > > 
> > > Since this is a pr_warn, I get the feeling something is not quite right.
> > > Is there something to fix? Is it a problem that the big and little cores
> > > don't support exactly the same granule sizes?
> > > 
> > 
> > That looks like a false positive to me. We should only care about the
> > page size we are running with.
> 
> Unless you run a VM, which is going to use 16K translation. But this may be
> fine with the current kernels, where we emulate the SANITISED registers
> for the guests.

I think that's sanitised now for KVM, so we could downgrade the feature
to FTR_NONSTRICT.

-- 
Catalin

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  parent reply	other threads:[~2018-12-03 15:32 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-30 12:15 Unexpected variation in SYS_ID_AA64MMFR0_EL1 Marc Gonzalez
2018-11-30 13:12 ` Ard Biesheuvel
2018-11-30 13:23   ` Suzuki K Poulose
2018-11-30 13:24     ` Ard Biesheuvel
2018-12-03 15:32     ` Catalin Marinas [this message]
2018-12-05 10:17       ` Suzuki K Poulose
2018-12-05 15:53         ` Catalin Marinas

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