Re: [PATCH 2/3] drm/amdkfd: svm unmap use page aligned address

["Chen, Xiaogang" <xiaogang.chen@amd.com>]

On 10/2/2025 12:43 PM, Philip Yang wrote:
> svm_range_unmap_from_gpus uses page aligned start, end address, the end
> address is inclusive.
>
> Fixes: 38c55f6719f7 ("drm/amdkfd: Handle lack of READ permissions in SVM mapping")
> Signed-off-by: Philip Yang <Philip.Yang@amd.com>
> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> index e8a15751c125..742c28833650 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> @@ -1723,8 +1723,8 @@ static int svm_range_validate_and_map(struct mm_struct *mm,
>   				svm_range_lock(prange);
>   				if (vma->vm_flags & VM_WRITE)
>   					pr_debug("VM_WRITE without VM_READ is not supported");
> -				s = max(start, prange->start);
> -				e = min(end, prange->last);
> +				s = max(start >> PAGE_SHIFT, prange->start);
> +				e = min((end - 1) >> PAGE_SHIFT, prange->last);

I think the problem is more than that. Here "end" is the last place for 
prange gpu mapping and the handling here is for a vma. Should use end of 
the vma range to get "e".

Regards

Xiaogang

>   				if (e >= s)
>   					r = svm_range_unmap_from_gpus(prange, s, e,
>   						       KFD_SVM_UNMAP_TRIGGER_UNMAP_FROM_CPU);