Re: [PATCH v3 10/21] KVM:x86: Add #CP support in guest exception classification

[Yang, Weijiang]

On 6/16/2023 7:58 AM, Sean Christopherson wrote:
> On Thu, Jun 08, 2023, Weijiang Yang wrote:
> > On 6/6/2023 5:08 PM, Chao Gao wrote:
> > > On Thu, May 11, 2023 at 12:08:46AM -0400, Yang Weijiang wrote:
> > > > Add handling for Control Protection (#CP) exceptions(vector 21).
> > > > The new vector is introduced for Intel's Control-Flow Enforcement
> > > > Technology (CET) relevant violation cases.
> > > >
> > > > Although #CP belongs contributory exception class, but the actual
> > > > effect is conditional on CET being exposed to guest. If CET is not
> > > > available to guest, #CP falls back to non-contributory and doesn't
> > > > have an error code.
> > > This sounds weird. is this the hardware behavior? If yes, could you
> > > point us to where this behavior is documented?
> > It's not SDM documented behavior.
> The #CP behavior needs to be documented.  Please pester whoever you need to in
> order to make that happen.

Do you mean documentation for #CP as an generic exception or the 
behavior in KVM as

this patch shows?