Re: [PATCH v8 5/8] KVM: Register/unregister the guest private memory regions

[Sean Christopherson]

On Wed, Oct 19, 2022, Fuad Tabba wrote:
> > > > This sounds good. Thank you.
> > >
> > > I like the idea of a separate Kconfig, e.g. CONFIG_KVM_GENERIC_PRIVATE_MEM or
> > > something.  I highly doubt there will be any non-x86 users for multiple years,
> > > if ever, but it would allow testing the private memory stuff on ARM (and any other
> > > non-x86 arch) without needing full pKVM support and with only minor KVM
> > > modifications, e.g. the x86 support[*] to test UPM without TDX is shaping up to be
> > > trivial.
> >
> > CONFIG_KVM_GENERIC_PRIVATE_MEM looks good to me.
> 
> That sounds good to me, and just keeping the xarray isn't really an
> issue for pKVM.

The xarray won't exist for pKVM if the #ifdefs in this patch are changed from
CONFIG_HAVE_KVM_PRIVATE_MEM => CONFIG_KVM_GENERIC_PRIVATE_MEM.

> We could end up using it instead of some of the other
> structures we use for tracking.

I don't think pKVM should hijack the xarray for other purposes.  At best, it will
be confusing, at worst we'll end up with a mess if ARM ever supports the "generic"
implementation.