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

Xiaoyao Li
2025-09-16T07:07:29Z

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?

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

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