linux-kernel - Re: [PATCH v7 7/8] KVM: VMX: Expose PKS to guest

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Yo1rfrnV5nObIHJK@google.com>
Date:   Tue, 24 May 2022 23:34:22 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Lei Wang <lei4.wang@...el.com>
Cc:     pbonzini@...hat.com, vkuznets@...hat.com, wanpengli@...cent.com,
        jmattson@...gle.com, joro@...tes.org, chenyi.qiang@...el.com,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 7/8] KVM: VMX: Expose PKS to guest

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.