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

Sean Christopherson
2025-09-19T22:11:22Z

On Tue, Sep 16, 2025, Xiaoyao Li wrote:
> On 9/13/2025 7:22 AM, Sean Christopherson wrote:
> > From: Yang Weijiang <weijiang.yang@intel.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@google.com>
> > Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
> > Tested-by: Mathias Krause <minipli@grsecurity.net>
> > Tested-by: John Allen <john.allen@amd.com>
> > Tested-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
> > Signed-off-by: Chao Gao <chao.gao@intel.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?

Yes? My comment there is stating what I did relative to the patch Chao sent.
It's not relative to any existing code.