Re: [PATCH 0/4] Introduce nvgrace-egm driver for Extended GPU Memory

[Jason Gunthorpe]

On Tue, Aug 04, 2026 at 09:24:47AM +0200, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
> On Mon, Aug 03, 2026 at 04:43:38PM +0000, Ankit Agrawal wrote:
> > Hi
> > 
> > Gentle ping on this series. Happy to respin to address the feedbacks
> > or concerns if needed.
> 
> There is no context here :(
> 
> Also, you are adding custom ioctls for memory and drm things, why is the
> mm and drm people not part of the review here as this seems to interact
> / go around those subsystems?

The cover letter does explain this, the memory is CPU DRAM, so there
is nothing related to DRM. It is reserved by FW so it doesn't get a
struct page or zone, so there is no direct mm connection.

We don't want to waste system memory on a useless struct page here,
this could be 100GB's of memory potentially.

The call to register_pfn_address_space() follows how vfio was done and
this was all gone over with mm a while ago.

The single ioctl is not "memory and drm things", it is reporting a
table from the BIOS indicating portions of the FW reserved memory that
has been recorded as unreliable that should be avoided.

> And where is the userspace code that will be using this new api?

The cover letter hints at this, it is usable via existing qemu
features using the "-object memory-backend-file" or similar.  Ankit
you could probably make that section a bit more specific if you
respin.

Jason