Re: [PATCH v11 0/8] KVM: allow mapping non-refcounted pages

[Christoph Hellwig]

On Wed, Mar 13, 2024 at 01:55:20PM +0900, David Stevens wrote:
> On Thu, Feb 29, 2024 at 10:36 PM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> >
> > On Thu, Feb 29, 2024 at 11:57:51AM +0900, David Stevens wrote:
> > > Our use case is virtio-gpu blob resources [1], which directly map host
> > > graphics buffers into the guest as "vram" for the virtio-gpu device.
> > > This feature currently does not work on systems using the amdgpu driver,
> > > as that driver allocates non-compound higher order pages via
> > > ttm_pool_alloc_page().
> >
> > .. and just as last time around that is still the problem that needs
> > to be fixed instead of creating a monster like this to map
> > non-refcounted pages.
> >
> 
> Patches to amdgpu to have been NAKed [1] with the justification that
> using non-refcounted pages is working as intended and KVM is in the
> wrong for wanting to take references to pages mapped with VM_PFNMAP
> [2].

So make them not work for KVM as they should to kick the amdgpu
maintainers a***es.