Re: [PATCH v3 2/2] KVM: X86: Introduce KVM_HC_PAGE_ENC_STATUS hypercall

[Sean Christopherson]

On Tue, May 04, 2021, Paolo Bonzini wrote:
> On 04/05/21 19:09, Sean Christopherson wrote:
> > On Sat, May 01, 2021, Paolo Bonzini wrote:
> > > - make it completely independent from migration, i.e. it's just a facet of
> > > MSR_KVM_PAGE_ENC_STATUS saying whether the bitmap is up-to-date.  It would
> > > use CPUID bit as the encryption status bitmap and have no code at all in KVM
> > > (userspace needs to set up the filter and implement everything).
> > 
> > If the bit is purely a "page encryption status is up-to-date", what about
> > overloading KVM_HC_PAGE_ENC_STATUS to handle that status update as well?   That
> > would eliminate my biggest complaint about having what is effectively a single
> > paravirt feature split into two separate, but intertwined chunks of ABI.
> 
> It's true that they are intertwined, but I dislike not having a way to read
> the current state.

>From the guest?