linux-kernel - Re: [PATCH v8 3/6] KVM: x86: Virtualize CR3.LAM

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Message-ID: <ZFtcwACy/1rn2Py1@chao-email>
Date:   Wed, 10 May 2023 16:58:40 +0800
From:   Chao Gao <chao.gao@...el.com>
To:     Binbin Wu <binbin.wu@...ux.intel.com>
CC:     <kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <seanjc@...gle.com>, <pbonzini@...hat.com>, <kai.huang@...el.com>,
        <robert.hu@...ux.intel.com>
Subject: Re: [PATCH v8 3/6] KVM: x86: Virtualize CR3.LAM_{U48,U57}

>@@ -7743,6 +7744,9 @@ static void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
> 		vmx->msr_ia32_feature_control_valid_bits &=
> 			~FEAT_CTL_SGX_LC_ENABLED;
> 
>+	if (guest_cpuid_has(vcpu, X86_FEATURE_LAM))
>+		vcpu->arch.cr3_ctrl_bits |= X86_CR3_LAM_U48 | X86_CR3_LAM_U57;

This function can be called multiple times. We need to clear LAM bits if LAM
isn't exposed to the guest, i.e.,

	else
		vcpu->arch.cr3_ctrl_bits &= ~(X86_CR3_LAM_U48 | X86_CR3_LAM_U57);

With this fixed,

Reviewed-by: Chao Gao <chao.gao@...el.com>