Re: [RFC PATCH v2 00/11] KVM: Mapping guest_memfd backed memory at the host for software protected VMs

[Fuad Tabba <tabba@google.com>]

Hi David,

On Thu, 30 Jan 2025 at 16:50, David Hildenbrand <david@redhat.com> wrote:
>
> On 29.01.25 18:23, Fuad Tabba wrote:
>
> Thanks for the new version
>
> > Main changes since v1 [1]:
> > - Added x86 support for mapping guest_memfd at the host, enabled
> >   only for the KVM_X86_SW_PROTECTED_VM type.
>
> Nice!
>
> > - Require setting memslot userspace_addr for guest_memfd slots
> >   even if shared, and remove patches that worked around that.
> > - Brought in more of the infrastructure from the patch series
> >   that allows restricted mapping of guest_memfd backed memory.
>
> Ah, that explains why we see the page_type stuff in here now :)
>
> > - Renamed references to "mappable" -> "shared".
> > - Expanded the selftests.
> > - Added instructions to test on x86 and arm64 (below).
>
> Very nice!
>
>
> I assume there is still no page conversion happening -- or is there now
> that the page_stuff thing is in here?
>
> Would be good to spell out what's supported and what's still TBD
> regarding mmap support.

Thanks! No page conversion happening yet. I'm rebasing the other
series, the one with the conversions, on top of this one, as well as
fixing it based on the feedback that I got.

What this is missing is the infrastructure that tracks the
mappability/shareability at the host and the guest, as well as the
implementation of the callbacks themselves. I thought I'd send this
one out now, while I work on the larger one, since this one is easier
to test, and serves as a base for the coming part.

Cheers,
/fuad

> --
> Cheers,
>
> David / dhildenb
>