Re: [PATCH v7 00/14] KVM: mm: fd-based approach for supporting KVM guest private memory

Chao Peng
2022-08-24T10:32:44Z

On Sun, Aug 21, 2022 at 11:27:44AM +0100, Matthew Wilcox wrote:
> On Thu, Aug 18, 2022 at 08:00:41PM -0700, Hugh Dickins wrote:
> > tmpfs and hugetlbfs and page cache are designed around sharing memory:
> > TDX is designed around absolutely not sharing memory; and the further
> > uses which Sean foresees appear not to need it as page cache either.
> >
> > Except perhaps for page migration reasons. It's somewhat incidental,
> > but of course page migration knows how to migrate page cache, so
> > masquerading as page cache will give a short cut to page migration,
> > when page migration becomes at all possible.
>
> I haven't read the patch series, and I'm not taking a position one way
> or the other on whether this is better implemented as a shmem addition
> or a shim that asks shmem for memory. Page migration can be done for
> driver memory by using PageMovable. I just rewrote how it works, so
> the details are top of my mind at the moment if anyone wants something
> explained. Commit 68f2736a8583 is the key one to look at.

Thanks Matthew. That is helpful to understand the current code.

Chao