Re: [PATCH v12 00/16] Direct Map Removal Support for guest_memfd

[Brendan Jackman]

On Wed May 6, 2026 at 8:07 AM UTC, Takahiro Itazuri wrote:
> Hi Lorenzo and Sean,
>
> Apologies for the delayed reply — Nikita is leaving Amazon, and I'm
> taking over this series going forward. Thanks for your patience.
>
> On Tue, Apr 21, 2026 at 01:40:00PM +0000, Lorenzo Stoakes wrote:
>> Hm, given this touches a fair bit of mm, I wonder if we shouldn't try to do this
>> through the mm tree?
>
> On Tue, Apr 21, 2026 at 04:36:00PM +0000, Sean Christopherson wrote:
>> Yeah, when the time comes, the mm pieces definitely need to go through the mm
>> tree.  Ideally, I think this would be merged in two separate parts, with all mm
>> changes going through the mm tree, and then the KVM changes through the KVM tree
>> using a stable topic branch/tag from Andrew.
>
> Thanks for the guidance. The split makes sense to me; I'm planning to
> follow this approach with patches 1-6 (mm) going through the mm tree
> and patches 7-16 (KVM) through the KVM tree on top of a stable
> branch/tag from mm. I'll confirm the exact boundary and coordination
> details as I prepare the repost.
>
> On Tue, Apr 21, 2026 at 01:40:00PM +0000, Lorenzo Stoakes wrote:
>> In any case, we definitely need a rebase on something not-next :) if not mm then
>> Linus's tree at least maybe?
>>
>> I'm seeing a lot of conflicts against mm-unstable, it can't b4 shazam even patch
>> 1 and in Linus's tree it's failing at an mm patch (mm: introduce
>> AS_NO_DIRECT_MAP).
>

Just as an FYI, I am gonna look at trying to move this forward a bit
while Takahiro ramps up on taking over (I spoke to him about this off
list).

My ulterior motive is that this would give me an excuse to add
ALLOC_UNMAPPED (formerly __GFP_UNMAPPED) and the mermap [0] which
unblocks various security nonsense including ASI [1]. (But also, this
feature is a good idea).

[0] https://lore.kernel.org/all/20260320-page_alloc-unmapped-v2-0-28bf1bd54f41@xxxxxxxxxx/
[1] https://linuxasi.dev