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Date: Fri, 3 May 2024 13:01:27 +0200 (CEST)
From: Sebastian Ott <sebott@redhat.com>
To: Oliver Upton <oliver.upton@linux.dev>
cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, 
    linux-kernel@vger.kernel.org, Marc Zyngier <maz@kernel.org>, 
    James Morse <james.morse@arm.com>, 
    Suzuki K Poulose <suzuki.poulose@arm.com>, 
    Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>
Subject: Re: [PATCH v2 0/6] KVM: arm64: emulation for CTR_EL0
In-Reply-To: <ZjH6mgJa-ilmPu95@linux.dev>
Message-ID: <c7dad35e-1a7f-74fc-95f9-ffd9cdd53f95@redhat.com>
References: <20240426104950.7382-1-sebott@redhat.com> <ZjH6mgJa-ilmPu95@linux.dev>
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Hi Oliver,

On Wed, 1 May 2024, Oliver Upton wrote:
> On Fri, Apr 26, 2024 at 12:49:44PM +0200, Sebastian Ott wrote:
>> Hej folks,
>>
>> I'm looking into supporting migration between 2 Ampere Altra (Max)
>> machines (using Neoverse-N1). They are almost identical regarding
>> their feature id register state except for CTR_EL0.DIC which is set
>> on one machine but not the other.
>>
>> CTR_EL0 is currently marked as invariant and migrating a VM between
>> those 2 machines using qemu fails.
>
> I left some feedback on the series, but in addition to that would it be
> possible to augment the set_id_regs selftest to exercise the CTR_EL0
> mutability?

Yes, sure!

Thanks,
Sebastian