Re: [RFC PATCH v2 14/32] x86: mm: Provide support to use memblock when spliting large pages

On 16/03/2017 19:28, Borislav Petkov wrote:

So how hard would it be if the hypervisor allocated that memory for the
guest instead? It would allocate it decrypted and guest would need to
access it decrypted too. All in preparation for SEV-ES which will need a
block of unencrypted memory for the guest anyway...

The kvmclock memory is initially zero so there is no need for the
hypervisor to allocate anything; the point of these patches is just to
access the data in a natural way from Linux source code.

I also don't really like the patch as is (plus it fails modpost), but
IMO reusing __change_page_attr and __split_large_page is the right thing
to do.

Paolo