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From: Oliver Upton <oliver.upton@linux.dev>
To: kvmarm@lists.linux.dev
Cc: kvm@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>
Subject: Re: [PATCH 1/3] KVM: arm64: Don't zero VTTBR in __tlb_switch_to_host()
Date: Fri, 6 Oct 2023 09:41:33 +0000	[thread overview]
Message-ID: <ZR_WTS-bqrd3L5j2@linux.dev> (raw)
In-Reply-To: <20231006093600.1250986-2-oliver.upton@linux.dev>

On Fri, Oct 06, 2023 at 09:35:58AM +0000, Oliver Upton wrote:
> HCR_EL2.TGE=0 is sufficient to disable stage-2 translation, so there's

TGE=1, obviously :)

> no need to explicitly zero VTTBR_EL2. Note that this is exactly what we
> do on the guest exit path in __kvm_vcpu_run_vhe() already.
> 
> Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
> ---
>  arch/arm64/kvm/hyp/vhe/tlb.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/arch/arm64/kvm/hyp/vhe/tlb.c b/arch/arm64/kvm/hyp/vhe/tlb.c
> index 46bd43f61d76..f3f2e142e4f4 100644
> --- a/arch/arm64/kvm/hyp/vhe/tlb.c
> +++ b/arch/arm64/kvm/hyp/vhe/tlb.c
> @@ -66,7 +66,6 @@ static void __tlb_switch_to_host(struct tlb_inv_context *cxt)
>  	 * We're done with the TLB operation, let's restore the host's
>  	 * view of HCR_EL2.
>  	 */
> -	write_sysreg(0, vttbr_el2);
>  	write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
>  	isb();
>  
> -- 
> 2.42.0.609.gbb76f46606-goog
> 

-- 
Thanks,
Oliver

  reply	other threads:[~2023-10-06  9:41 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-06  9:35 [PATCH 0/3] KVM: arm64: Load the stage-2 MMU from vcpu_load() for VHE Oliver Upton
2023-10-06  9:35 ` [PATCH 1/3] KVM: arm64: Don't zero VTTBR in __tlb_switch_to_host() Oliver Upton
2023-10-06  9:41   ` Oliver Upton [this message]
2023-10-06  9:35 ` [PATCH 2/3] KVM: arm64: Rename helpers for VHE vCPU load/put Oliver Upton
2023-10-06 22:06   ` kernel test robot
2023-10-06  9:36 ` [PATCH 3/3] KVM: arm64: Load the stage-2 MMU context in kvm_vcpu_load_vhe() Oliver Upton
2023-10-06 11:13 ` [PATCH 0/3] KVM: arm64: Load the stage-2 MMU from vcpu_load() for VHE Marc Zyngier
2023-10-06 12:34   ` Marc Zyngier
2023-10-06 13:33     ` Marc Zyngier
2023-10-06 15:03       ` Marc Zyngier
2023-10-06 18:11         ` Oliver Upton

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