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Date:   Tue, 24 May 2022 23:34:22 +0000
From:   Sean Christopherson <seanjc@google.com>
To:     Lei Wang <lei4.wang@intel.com>
Cc:     pbonzini@redhat.com, vkuznets@redhat.com, wanpengli@tencent.com,
        jmattson@google.com, joro@8bytes.org, chenyi.qiang@intel.com,
        kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 7/8] KVM: VMX: Expose PKS to guest
Message-ID: <Yo1rfrnV5nObIHJK@google.com>
References: <20220424101557.134102-1-lei4.wang@intel.com>
 <20220424101557.134102-8-lei4.wang@intel.com>
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On Sun, Apr 24, 2022, Lei Wang wrote:
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 9d0588e85410..cbcb0d7b47a4 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -3250,7 +3250,7 @@ void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
>  		}
>  
>  		/*
> -		 * SMEP/SMAP/PKU is disabled if CPU is in non-paging mode in
> +		 * SMEP/SMAP/PKU/PKS is disabled if CPU is in non-paging mode in
>  		 * hardware.  To emulate this behavior, SMEP/SMAP/PKU needs

Heh, missed one ;-)  Let's reduce future pain and reword this whole comment:

		/*
		 * SMEP/SMAP/PKU/PKS are effectively disabled if the CPU is in
		 * non-paging mode in hardware.  To emulate this behavior,
		 * clear them in the hardware CR4 when the guest switches to
		 * non-paging mode and unrestricted guest is disabled, as KVM
		 * must run the guest with hardware CR0.PG=1.
		 */


>  		 * to be manually disabled when guest switches to non-paging
>  		 * mode.