Re: [PATCH v16 21/51] KVM: x86/mmu: WARN on attempt to check permissions for Shadow Stack #PF

[Xiaoyao Li]

On 9/22/2025 3:46 PM, Binbin Wu wrote:
> On 9/22/2025 3:17 PM, Binbin Wu wrote:
> > On 9/20/2025 6:32 AM, Sean Christopherson wrote:
> > > Add PFERR_SS_MASK, a.k.a. Shadow Stack access, and WARN if KVM 
> > > attempts to
> > > check permissions for a Shadow Stack access as KVM hasn't been taught to
> > > understand the magic Writable=0,Dirty=0 combination that is required for
> Typo:
>
> Writable=0,Dirty=0 -> Writable=0,Dirty=1

With it fixed,

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

> > > Shadow Stack accesses, and likely will never learn.  There are no 
> > > plans to
> > > support Shadow Stacks with the Shadow MMU, and the emulator rejects all
> > > instructions that affect Shadow Stacks, i.e. it should be impossible for
> > > KVM to observe a #PF due to a shadow stack access.
> > >
> > > Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> >
> > Reviewed-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>