Re: [PATCH RFC v3 0/2] mm: Refactor KVM guest_memfd to introduce guestmem library

[David Hildenbrand]

On 13.11.24 23:34, Elliot Berman wrote:
> In preparation for adding more features to KVM's guest_memfd, refactor
> and introduce a library which abtracts some of the core-mm decisions
> about managing folios associated with guest memory. The goal of the
> refactor serves two purposes:
>
> 1. Provide an easier way to reason about memory in guest_memfd. KVM
>     needs to support multiple confidentiality models (TDX, SEV, pKVM, Arm
>     CCA). These models support different semantics for when the host
>     can(not) access guest memory. An abstraction for the allocator and
>     managing the state of pages will make it eaiser to reason about the
>     state of folios within the guest_memfd.
>
> 2. Provide a common implementation for other users such as Gunyah [1] and
>     guestmemfs [2].
>
> In this initial series, I'm seeking comments for the line I'm drawing
> between library and user (KVM). I've not introduced new functionality in
> this series; the first new feature will probably be Fuad's mappability
> patches [3].

Right, or the dummy mmap + vma->set_policy patches for NUMA handling.

--
Cheers,

David / dhildenb