linux-kernel - Re: [PATCH v15 14/41] KVM: VMX: Emulate read and write to CET MSRs

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Message-ID: <5afee11a-c4e9-4f44-85b8-006ab1b1433f@intel.com>
Date: Tue, 16 Sep 2025 15:07:06 +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 14/41] KVM: VMX: Emulate read and write to CET MSRs

On 9/13/2025 7:22 AM, Sean Christopherson wrote:
> From: Yang Weijiang <weijiang.yang@...el.com>
> 
> Add emulation interface for CET MSR access. The emulation code is split
> into common part and vendor specific part. The former does common checks
> for MSRs, e.g., accessibility, data validity etc., then passes operation
> to either XSAVE-managed MSRs via the helpers or CET VMCS fields.
> 
> SSP can only be read via RDSSP. Writing even requires destructive and
> potentially faulting operations such as SAVEPREVSSP/RSTORSSP or
> SETSSBSY/CLRSSBSY. Let the host use a pseudo-MSR that is just a wrapper
> for the GUEST_SSP field of the VMCS.
> 
> Suggested-by: Sean Christopherson <seanjc@...gle.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>
> [sean: drop call to kvm_set_xstate_msr() for S_CET, consolidate code]

Is the change/update of "drop call to kvm_set_xstate_msr() for S_CET" 
true for this patch?

> Signed-off-by: Sean Christopherson <seanjc@...gle.com>

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