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From: Mark Rutland <mark.rutland@arm.com>
To: Andrew Jones <drjones@redhat.com>
Cc: marc.zyngier@arm.com, pbonzini@redhat.com,
	kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
	shannon.zhao@linaro.org
Subject: Re: [kvm-unit-tests PATCH] arm/arm64: introduce is_aarch32
Date: Thu, 17 Nov 2016 17:47:51 +0000	[thread overview]
Message-ID: <20161117174751.GD21742@leverpostej> (raw)
In-Reply-To: <20161117164541.uwmearukm3zcwahh@hawk.localdomain>

On Thu, Nov 17, 2016 at 05:45:41PM +0100, Andrew Jones wrote:
> Hi Mark,
> 
> On Wed, Nov 16, 2016 at 05:45:44PM +0000, Mark Rutland wrote:
> > So I don't think we should try to distinguish ARMv8-A AArch32 from
> > ARMv7-A. We should test individual features, or if that's not possible,
> > group them in the same bucket.
> 
> Perhaps I was too quick to look for a general way to approach the first
> place I saw the need, which is
> 
>  check_cntr(read_pmccntr());
>  if (is_aarch64())
>      check_cntr(read_pmccntr64());
> 
> Is PMCCNTR the only "weird" difference?

Define "weird". ;)

I believe the extension of PMCCNTR to 64 bits is part of PMUv3. So you
should be able to check ID_DFR0.PerfMon == 0b0011. For overflow you'll
also need to configure PMCR.LC.

Thanks,
Mark.

  reply	other threads:[~2016-11-17 17:47 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-16 14:38 [kvm-unit-tests PATCH] arm/arm64: introduce is_aarch32 Andrew Jones
2016-11-16 17:42 ` Andre Przywara
2016-11-17 16:33   ` Andrew Jones
2016-11-16 17:45 ` Mark Rutland
2016-11-17 16:45   ` Andrew Jones
2016-11-17 17:47     ` Mark Rutland [this message]
2016-11-18 10:57       ` Andrew Jones
2016-11-16 17:46 ` Marc Zyngier
2016-11-16 22:02   ` Christopher Covington
2016-11-17  6:45     ` Wei Huang
2016-11-17 16:59     ` Andrew Jones
2016-11-18 15:06       ` Christopher Covington

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