linux-kernel - Re: [PATCH v5 08/19] KVM:x86: Report KVM supported CET MSRs as to-be-saved

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Date:   Fri, 4 Aug 2023 23:47:07 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Yang Weijiang <weijiang.yang@...el.com>, seanjc@...gle.com,
        peterz@...radead.org, john.allen@....com, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     rick.p.edgecombe@...el.com, chao.gao@...el.com,
        binbin.wu@...ux.intel.com
Subject: Re: [PATCH v5 08/19] KVM:x86: Report KVM supported CET MSRs as
 to-be-saved

On 8/3/23 06:27, Yang Weijiang wrote:
> Add all CET MSRs including the synthesized GUEST_SSP to report list.
> PL{0,1,2}_SSP are independent to host XSAVE management with later
> patches. MSR_IA32_U_CET and MSR_IA32_PL3_SSP are XSAVE-managed on
> host side. MSR_IA32_S_CET/MSR_IA32_INT_SSP_TAB/MSR_KVM_GUEST_SSP
> are not XSAVE-managed.

MSR_KVM_GUEST_SSP -> MSR_KVM_SSP

Also please add a comment,

/*
  * 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.
  */

Paolo