Re: [PATCH v3 4/6] drm/xe/xe_ras: Add function to get maximum pages firmware can store

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] xe: max_entries from firmware response lost during paginated fetch
--

commit 7e32ecac1950627e3285eb91a4b340622535f4c7
Author: Riana Tauro <riana.tauro@intel.com>

drm/xe/xe_ras: Add function to get maximum pages firmware can store

Add function to get maximum number of pages that firmware can store for
offline tracking. This will be used to report max pages to userspace.

> diff --git a/drivers/gpu/drm/xe/xe_ras.c b/drivers/gpu/drm/xe/xe_ras.c
> index f7232429080a8..749cf25e9148a 100644
> --- a/drivers/gpu/drm/xe/xe_ras.c
> +++ b/drivers/gpu/drm/xe/xe_ras.c
> @@ -401,9 +401,13 @@ static void get_offlined_list(struct xe_device *xe)
>  {
>  	struct xe_ras_offline_list_response response = {0};
>  	struct xe_ras_offline_list_request request = {0};
> +	struct xe_ras_state *state = &xe->ras.state;
>  
>  	get_offline_pages(xe, XE_SYSCTRL_CMD_GET_OFFLINE_LIST, &request, sizeof(request),
>  			  &response, sizeof(response), &response.common, false);
> +
> +	if (response.max_entries)
> +		state->max_pages = response.max_entries;

[Severity: Medium]
Is it possible for the max_entries value to be lost here if the offline
list requires multiple chunks to fetch?

Looking at get_offline_pages() in the same file, the response buffer is
cleared at the beginning of every iteration:

static void get_offline_pages(...)
{
	...
	do {
		memset(resp, 0, resp_size);
		...
		ret = xe_sysctrl_send_command(&xe->sc, &command, &rlen);
	...
	} while (common->additional_data);
}

If the firmware only populates max_entries in the first chunk of the
paginated fetch, wouldn't the memset() overwrite it with zeros in
subsequent iterations?

By the time get_offlined_list() checks response.max_entries, it only
contains data from the final chunk. Could this result in max_pages
remaining 0?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260928061830.417395-8-riana.tauro@intel.com?part=4