Re: [PATCH 05/21] KVM: VMX: Teach EPT violation helper about private mem

[Sean Christopherson <seanjc@google.com>]

On Thu, Sep 12, 2024, Kai Huang wrote:
> > +static inline bool kvm_is_private_gpa(struct kvm *kvm, gpa_t gpa)
> > +{
> > +	/* For TDX the direct mask is the shared mask. */
> > +	return !kvm_is_addr_direct(kvm, gpa);
> > +}
> 
> Does this get used in any other places?  If no I think we can open code this
> in the __vmx_handle_ept_violation().
> 
> The reason is I think the name kvm_is_private_gpa() is too generic and this
> is in the header file.

+1, kvm_is_private_gpa() is much too generic.  I knew what the code was *supposed*
to do, but had to look at the implementation to verify that's actually what it did.

> E.g., one can come up with another kvm_is_private_gpa() checking the memory
> attributes to tell whether a GPA is private.
> 
> Or we rename it to something like
> 
> 	__vmx_is_faulting_gpa_private()
> ?
> 
> Which clearly says it is checking the *faulting* GPA.

I don't think that necessarily solves the problem either, because the reader has
to know that the KVM looks at the shared bit.

If open coding is undesirable, maybe a very literal name, e.g. vmx_is_shared_bit_set()?