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From: Marc Zyngier <marc.zyngier@arm.com>
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Date: Mon, 29 Oct 2018 15:56:58 +0000
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Subject: Re: [Qemu-devel] [PATCH 4/5] target/arm: Fill in ARMISARegisters
 for kvm32
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: Richard Henderson <richard.henderson@linaro.org>, QEMU Developers <qemu-devel@nongnu.org>, Christoffer Dall <christoffer.dall@arm.com>

On 29/10/18 15:48, Peter Maydell wrote:
> On 29 October 2018 at 15:40, Marc Zyngier <marc.zyngier@arm.com> wrote:
>> My temptation would be not to expose it at all when running on a v7
>> core, and return an error rather than zero.
>>
>> The other issue is that we currently don't support running 32bit KVM on
>> any ARMv8 platform, as we strictly check the CPUs we want to run on (A7
>> and A15). I remember seeing patches that would allow any host core to be
>> used (similar to what we have on the 64bit side), but that never made it
>> in the tree.
> 
> Ah, that's convenient in some ways. It means we can define the
> API to be "for v7, no register available via the ONE_REG API;
> for v8, always present", provided we add the constant and the
> support before we turn on any actual v8 CPUs for 32-bit KVM
> (avoiding the awkward case of "v8 but kernel doesn't expose
> MVFR2").
> 
> I don't think we particularly care about the 32-bit-kvm-on-v8
> part, but it would be good to nail down this wrinkle so we don't
> forget about it, maybe ?

Absolutely. I'll write something up.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...