On Fri, Apr 26, 2024 at 04:32:36PM -0700, Matthew Brost wrote:
> To be secure, when a userptr is invalidated the pages should be dma
> unmapped ensuring the device can no longer touch the invalidated pages.
>
> Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
> Fixes: 12f4b58a37f4 ("drm/xe: Use hmm_range_fault to populate user pages")
> Cc: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx # 6.8
> Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
> ---
> drivers/gpu/drm/xe/xe_vm.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> index dfd31b346021..964a5b4d47d8 100644
> --- a/drivers/gpu/drm/xe/xe_vm.c
> +++ b/drivers/gpu/drm/xe/xe_vm.c
> @@ -637,6 +637,9 @@ static bool vma_userptr_invalidate(struct mmu_interval_notifier *mni,
> XE_WARN_ON(err);
> }
>
> + if (userptr->sg)
> + xe_hmm_userptr_free_sg(uvma);
> +
I thought about this a bit, I think here we only dma unmap the SG, not
free it. Freeing it could cause a current bind walk to access corrupt
memory. Freeing can be deferred to the next attempt to bind the userptr
or userptr destroy.
Matt
> trace_xe_vma_userptr_invalidate_complete(vma);
>
> return true;
> --
> 2.34.1
>
