Re: [PATCH v4 1/5] KVM: x86: Consolidate CPUID fault handling for emulator and interception logic

[Sean Christopherson <seanjc@google.com>]

On Thu, May 28, 2026, Jim Mattson wrote:
> On Thu, May 28, 2026 at 2:14 AM Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > On Wed, May 27, 2026 at 10:43:43AM -0700, Jim Mattson wrote:
> >
> > > [jim: Add EXPORT_STATIC_CALL_GPL(kvm_x86_get_cpl) so that KVM vendor
> > > modules can call kvm_is_cpuid_allowed(). Fix typo in commit message.]
> >
> > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > > index 1578c0ecbbd1..72bd3cddb026 100644
> > > --- a/arch/x86/kvm/x86.c
> > > +++ b/arch/x86/kvm/x86.c
> > > @@ -151,6 +151,7 @@ struct kvm_x86_ops kvm_x86_ops __read_mostly;
> > >  #include <asm/kvm-x86-ops.h>
> > >  EXPORT_STATIC_CALL_GPL(kvm_x86_get_cs_db_l_bits);
> > >  EXPORT_STATIC_CALL_GPL(kvm_x86_cache_reg);
> > > +EXPORT_STATIC_CALL_GPL(kvm_x86_get_cpl);
> >
> > Are you aware of the distinction between EXPORT_STATIC_CALL_GPL() and
> > EXPORT_STATIC_CALL_TRAMP_GPL() ?
> 
> I am now. :)
> 
> > Specifically, the former allows modules to do static_call_update(),
> > while the latter does not. Whenever possible use the TRAMP thing, this
> > allows modules to *call* the static_call, but not to redirect it.
> 
> Sean - Can you fix this up when you apply it, or do you want a v5?

Neither, as detailed in my other response, using EXPORT_STATIC_CALL_TRAMP_GPL()
requires switching kvm_x86_call() to static_call_mod().  We can do that, but I
want to do it separately.