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Date: Fri, 28 Jul 2023 09:14:14 +0100
Message-ID: <87h6poqwq1.wl-maz@kernel.org>
From: Marc Zyngier <maz@kernel.org>
To: Oliver Upton <oliver.upton@linux.dev>
Cc: kvmarm@lists.linux.dev,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>
Subject: Re: [PATCH] KVM: arm64: Skip instruction after emulating write to TCR_EL1
In-Reply-To: <20230728000824.3848025-1-oliver.upton@linux.dev>
References: <20230728000824.3848025-1-oliver.upton@linux.dev>
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On Fri, 28 Jul 2023 01:08:24 +0100,
Oliver Upton <oliver.upton@linux.dev> wrote:
> 
> Whelp, this is embarrassing. Since commit 082fdfd13841 ("KVM: arm64:
> Prevent guests from enabling HA/HD on Ampere1") KVM traps writes to
> TCR_EL1 on AmpereOne to work around an erratum in the unadvertised
> HAFDBS implementation, preventing the guest from enabling the feature.
> Unfortunately, I failed virtualization 101 when working on that change,
> and forgot to advance PC after instruction emulation.
> 
> Do the right thing and skip the MSR instruction after emulating the
> write.
> 
> Fixes: 082fdfd13841 ("KVM: arm64: Prevent guests from enabling HA/HD on Ampere1")
> Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

Oh hum... I think it is high time for a new PR to Paolo!

Acked-by: Marc Zyngier <maz@kernel.org>

	M.

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