[PATCH 4/4] mm: check the device private page owner in hmm_range_fault

[Jason Gunthorpe]

On Mon, Mar 16, 2020 at 08:32:16PM +0100, Christoph Hellwig wrote:
> Hmm range fault will succeed for any kind of device private memory,
> even if it doesn't belong to the calling entity.  While nouveau
> has some crude checks for that, they are broken because they assume
> nouveau is the only user of device private memory.  Fix this by
> passing in an expected pgmap owner in the hmm_range_fault structure.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> Fixes: 4ef589dc9b10 ("mm/hmm/devmem: device memory hotplug using ZONE_DEVICE")
> ---
>  drivers/gpu/drm/nouveau/nouveau_dmem.c | 12 ------------
>  include/linux/hmm.h                    |  2 ++
>  mm/hmm.c                               | 10 +++++++++-
>  3 files changed, 11 insertions(+), 13 deletions(-)

Nice

Reviewed-by: Jason Gunthorpe <jgg at mellanox.com>

Jason