From: Marc Zyngier <maz@kernel.org>
To: Sebastian Ott <sebott@redhat.com>
Cc: linux-arm-kernel@lists.infradead.org,
Oliver Upton <oliver.upton@linux.dev>
Subject: Re: [PATCH 2/4] KVM: arm64: ensure guest access to CTR_EL0 is trapped
Date: Mon, 18 Mar 2024 11:47:14 +0000 [thread overview]
Message-ID: <861q87224d.wl-maz@kernel.org> (raw)
In-Reply-To: <20240318111636.10613-3-sebott@redhat.com>
On Mon, 18 Mar 2024 11:16:34 +0000,
Sebastian Ott <sebott@redhat.com> wrote:
>
> Ensure that guest access to the CTR_EL0 register is trapped
> independent of cpu errata.
>
> Signed-off-by: Sebastian Ott <sebott@redhat.com>
> ---
> arch/arm64/include/asm/kvm_emulate.h | 7 +------
> 1 file changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> index b804fe832184..daaaf7664219 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h
> @@ -91,12 +91,7 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu)
> vcpu->arch.hcr_el2 |= HCR_TVM;
> }
>
> - if (cpus_have_final_cap(ARM64_HAS_EVT) &&
> - !cpus_have_final_cap(ARM64_MISMATCHED_CACHE_TYPE))
> - vcpu->arch.hcr_el2 |= HCR_TID4;
> - else
> - vcpu->arch.hcr_el2 |= HCR_TID2;
> -
> + vcpu->arch.hcr_el2 |= HCR_TID2;
NAK. This is a huge performance sync. You should only revert to this
when absolutely necessary.
M.
--
Without deviation from the norm, progress is not possible.
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next prev parent reply other threads:[~2024-03-18 11:47 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-18 11:16 [RFC] [PATCH 0/4] KVM: arm64: emulation for CTR_EL0 Sebastian Ott
2024-03-18 11:16 ` [PATCH 1/4] KVM: arm64: add emulation for CTR_EL0 register Sebastian Ott
2024-03-18 11:45 ` Marc Zyngier
2024-03-18 11:16 ` [PATCH 2/4] KVM: arm64: ensure guest access to CTR_EL0 is trapped Sebastian Ott
2024-03-18 11:47 ` Marc Zyngier [this message]
2024-03-18 11:16 ` [PATCH 3/4] KVM: arm64: show writable masks for feature registers Sebastian Ott
2024-03-18 12:03 ` Marc Zyngier
2024-03-18 18:20 ` Sebastian Ott
2024-03-19 9:50 ` Marc Zyngier
2024-03-18 18:22 ` Sebastian Ott
2024-03-18 11:16 ` [PATCH 4/4] KVM: selftests: aarch64: add tool to dump registers Sebastian Ott
2024-03-18 15:24 ` [RFC] [PATCH 0/4] KVM: arm64: emulation for CTR_EL0 Marc Zyngier
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