Re: [RFC PATCH 26/39] KVM: guest_memfd: Track faultability within a struct kvm_gmem_private

David Hildenbrand
2024-10-17T17:11:51Z

On 17.10.24 18:47, Jason Gunthorpe wrote:
> On Thu, Oct 17, 2024 at 10:58:29AM -0400, Peter Xu wrote:
>
>> My question was more torwards whether gmemfd could still expose the
>> possibility to be used in VA forms to other modules that may not support
>> fd+offsets yet.
>
> I keep hearing they don't want to support page pinning on a guestmemfd
> mapping, so VA based paths could not work.

For shared pages it absolutely must work. That's what I keep hearing :)

>
>> I think as long as we can provide gmemfd VMAs like what this series
>> provides, it sounds possible to reuse the old VA interfaces before the CoCo
>> interfaces are ready, so that people can already start leveraging gmemfd
>> backing pages.
>
> And you definitely can't get the private pages out of the VA interface
> because all the VMA PTEs of private pages are non-present by definition.

Agreed.

--
Cheers,

David / dhildenb