Re: [PATCH v6 4/7] drm/xe: Introduce helpers for xe_vram size

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] `query_mem_regions()` now reports VRAM `min_page_size` as `SZ_4K` instead of `PAGE_SIZE` on architectures with `PAGE_SIZE > 4K`, leading to userspace allocation failures.
--

--- Patch [4]: [PATCH v6 4/7] drm/xe: Introduce helpers for xe_vram size ---
commit 8d2aa91dbef321fc3453eaed963150727bdc7dd0
Author: Satyanarayana K V P <[email protected]>

drm/xe: Introduce helpers for xe_vram size

This commit introduces xe_vram_alignment() and xe_vram_needs_64k() helpers.
It updates various files in the xe driver to use these new helpers instead of
directly checking the XE_VRAM_FLAGS_NEED64K flag.

> diff --git a/drivers/gpu/drm/xe/xe_query.c b/drivers/gpu/drm/xe/xe_query.c
> index dc975f5953683..9af98f08b0e59 100644
> --- a/drivers/gpu/drm/xe/xe_query.c
> +++ b/drivers/gpu/drm/xe/xe_query.c
> @@ -289,8 +289,7 @@ static int query_mem_regions(struct xe_device *xe,
>  			mem_regions->mem_regions[mem_regions->num_mem_regions].instance =
>  				mem_regions->num_mem_regions;
>  			mem_regions->mem_regions[mem_regions->num_mem_regions].min_page_size =
> -				xe->info.vram_flags & XE_VRAM_FLAGS_NEED64K ?
> -				SZ_64K : PAGE_SIZE;
> +				xe_vram_alignment(xe);

[Severity: High]
Does this code report the minimum page size correctly on architectures where
PAGE_SIZE is greater than 4K?

The previous code returned PAGE_SIZE when 64K alignment was not needed, but
xe_vram_alignment() now always returns SZ_4K in that case.

If userspace uses this 4K value to size its allocations, could those
allocations be rejected in xe_gem_create_ioctl()?

drivers/gpu/drm/xe/xe_bo.c:xe_gem_create_ioctl() {
        ...
        if (XE_IOCTL_DBG(xe, args->size & ~PAGE_MASK))
                return -EINVAL;
        ...
}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=4