Re: [PATCH 03/19] mm: Mark special bits for huge pfn mappings when inject

Jason Gunthorpe
2024-08-14T12:40:04Z

On Fri, Aug 09, 2024 at 12:08:53PM -0400, Peter Xu wrote:
> We need these special bits to be around to enable gup-fast on pfnmaps.

It is not gup-fast you are after but follow_pfn/etc for KVM usage
right?

GUP family of functions should all fail on pfnmaps.

> Mark properly for !devmap case, reflecting that there's no page struct
> backing the entry.
>
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
> mm/huge_memory.c | 4 ++++
> 1 file changed, 4 insertions(+)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason