Re: [RFC PATCH 0/2] KVM: pfncache: Support guest_memfd without direct map

["David Hildenbrand (Red Hat)" <david@kernel.org>]

On 12/4/25 23:31, David Woodhouse wrote:
> On Wed, 2025-12-03 at 17:06 +0000, Brendan Jackman wrote:
>> Makes sense. I didn't properly explore if there are any challenges with
>> making vmalloc aware of it, but assuming there are no issues there I
>> don't think setting up an mm-local region is very challinging [1]. I
>> have the impression the main reason there isn't already an mm-local
>> region is just that the right usecase hasn't come along yet?
> 
> I'm fairly sure we have a *usecase* for mm-local.

Haha, I just skimmed over this patch and wondered "is mm-local a new mm 
branch we want to have" :)

> 
> And since researchers dusted off our XSA-289 advisory from 2019,
> rediscovered it and called it 'L1TF reloaded' and then expressed
> surprise that environments which have been using mm-local ever since
> those days don't actually leak secrets from one guest to another... I'd
> kind of hope that everyone else has come round to our way of thinking
> that we have a usecase for mm-local too? :)

Yeah, I would assume that we have such use cases indeed.

-- 
Cheers

David