linux-kernel - Re: [PATCH v15 11/41] KVM: x86: Report KVM supported CET MSRs as to-be-saved

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: <793a01d8-c439-45ee-a509-606245f42f07@intel.com>
Date: Mon, 15 Sep 2025 14:30:36 +0800
From: Xiaoyao Li <xiaoyao.li@...el.com>
To: Sean Christopherson <seanjc@...gle.com>,
 Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
 Tom Lendacky <thomas.lendacky@....com>,
 Mathias Krause <minipli@...ecurity.net>, John Allen <john.allen@....com>,
 Rick Edgecombe <rick.p.edgecombe@...el.com>, Chao Gao <chao.gao@...el.com>,
 Maxim Levitsky <mlevitsk@...hat.com>, Zhang Yi Z <yi.z.zhang@...ux.intel.com>
Subject: Re: [PATCH v15 11/41] KVM: x86: Report KVM supported CET MSRs as
 to-be-saved

On 9/13/2025 7:22 AM, Sean Christopherson wrote:
> From: Yang Weijiang <weijiang.yang@...el.com>
> 
> Add CET MSRs to the list of MSRs reported to userspace if the feature,
> i.e. IBT or SHSTK, associated with the MSRs is supported by KVM.
> 
> Suggested-by: Chao Gao <chao.gao@...el.com>
> Signed-off-by: Yang Weijiang <weijiang.yang@...el.com>
> Tested-by: Mathias Krause <minipli@...ecurity.net>
> Tested-by: John Allen <john.allen@....com>
> Tested-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
> Signed-off-by: Chao Gao <chao.gao@...el.com>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>

Reviewed-by: Xiaoyao Li <xiaoyao.li@...el.com>

> ---
>   arch/x86/kvm/x86.c | 18 ++++++++++++++++++
>   1 file changed, 18 insertions(+)
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 5653ddfe124e..2c9908bc8b32 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -344,6 +344,10 @@ static const u32 msrs_to_save_base[] = {
>   	MSR_IA32_UMWAIT_CONTROL,
>   
>   	MSR_IA32_XFD, MSR_IA32_XFD_ERR, MSR_IA32_XSS,
> +
> +	MSR_IA32_U_CET, MSR_IA32_S_CET,
> +	MSR_IA32_PL0_SSP, MSR_IA32_PL1_SSP, MSR_IA32_PL2_SSP,
> +	MSR_IA32_PL3_SSP, MSR_IA32_INT_SSP_TAB,
>   };
>   
>   static const u32 msrs_to_save_pmu[] = {
> @@ -7598,6 +7602,20 @@ static void kvm_probe_msr_to_save(u32 msr_index)
>   		if (!kvm_caps.supported_xss)
>   			return;
>   		break;
> +	case MSR_IA32_U_CET:
> +	case MSR_IA32_S_CET:
> +		if (!kvm_cpu_cap_has(X86_FEATURE_SHSTK) &&
> +		    !kvm_cpu_cap_has(X86_FEATURE_IBT))
> +			return;
> +		break;
> +	case MSR_IA32_INT_SSP_TAB:
> +		if (!kvm_cpu_cap_has(X86_FEATURE_LM))
> +			return;
> +		fallthrough;
> +	case MSR_IA32_PL0_SSP ... MSR_IA32_PL3_SSP:
> +		if (!kvm_cpu_cap_has(X86_FEATURE_SHSTK))
> +			return;
> +		break;
>   	default:
>   		break;
>   	}