Re: [RFC PATCH v5 033/104] KVM: x86: Add infrastructure for stolen GPA bits

[Paolo Bonzini]

On 4/1/22 04:34, Isaku Yamahata wrote:
> Sure, this patch heavily changed from the original patch Now.  One suggestion
> is that private/shared is characteristic to kvm page fault, not gpa/gfn.
> It's TDX specific.
>
> - Add a helper function to check if KVM MMU is TD or VM. Right now
>    kvm_gfn_stolen_mask() is used.  Probably kvm_mmu_has_private_bit().
>    (any better name?)

I think use of kvm_gfn_stolen_mask() should be minimized anyway.  I 
would rename it to to kvm_{gfn,gpa}_private_mask and not return bool.

> - Let's keep address conversion functions: address => unalias/shared/private

unalias is the same as private.  It doesn't seem to have a lot of uses. 
 I would just inline "x & ~gfn_private_mask", or "x & 
~kvm_gfn_private_mask(kvm)"; or the same with gpa of course.

The shared and private conversion functions should remain.

> - Add struct kvm_page_fault.is_private
>    see how kvm_is_private_{gpa, gfn}() can be removed (or reduced).

Agreed.

Paolo