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Date:   Fri, 9 Sep 2022 18:28:34 +0100
From:   Catalin Marinas <catalin.marinas@arm.com>
To:     Elliot Berman <quic_eberman@quicinc.com>
Cc:     Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
        James Morse <james.morse@arm.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH v2] KVM: arm64: Only set KVM_MODE_PROTECTED if
 is_hyp_mode_available()
Message-ID: <Yxt3wmXYYbWraXrd@arm.com>
References: <20220909144552.3000716-1-quic_eberman@quicinc.com>
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On Fri, Sep 09, 2022 at 07:45:52AM -0700, Elliot Berman wrote:
> Do not switch kvm_mode to KVM_MODE_PROTECTED if hypervisor mode is not
> available. This prevents "Protected KVM" cpu capability being reported
> when Linux is booting in EL1 and would not have KVM enabled.
> 
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>  arch/arm64/kvm/arm.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 8fe73ee5fa84..861f4b388879 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -2272,7 +2272,9 @@ static int __init early_kvm_mode_cfg(char *arg)
>  		return -EINVAL;
>  
>  	if (strcmp(arg, "protected") == 0) {
> -		if (!is_kernel_in_hyp_mode())
> +		if (!is_hyp_mode_available())
> +			kvm_mode = KVM_MODE_DEFAULT;

I think kvm_mode is already KVM_MODE_DEFAULT at this point. You may want
to print a warning instead.

-- 
Catalin