Re: Unmapping KVM Guest Memory from Host Kernel

Brendan Jackman
2024-03-08T16:25:35Z

Hi James

On Fri, 8 Mar 2024 at 16:50, Gowans, James <jgowans@amazon.com> wrote:
> Our goal is to more completely address the class of issues whose leak
> origin is categorized as "Mapped memory" [1].

Did you forget a link below? I'm interested in hearing about that
categorisation.

> ... what’s the best way to solve getting guest RAM out of
> the direct map?

It's perhaps a bigger hammer than you are looking for, but the
solution we're working on at Google is "Address Space Isolation" (ASI)
- the latest posting about that is [2].

The sense in which it's a bigger hammer is that it doesn't only
support removing guest memory from the direct map, but rather
arbitrary data from arbitrary kernel mappings.

[2] https://lore.kernel.org/linux-mm/CA+i-1C169s8pyqZDx+iSnFmftmGfssdQA29+pYm-gqySAYWgpg@mail.gmail.com/