Re: [PATCH v2 3/3] drm/xe/vf: Don't expose privileged GT debugfs files if VF

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

On 03.04.2025 22:28, Matthew Brost wrote:
> On Thu, Apr 03, 2025 at 04:26:35PM +0200, Michal Wajdeczko wrote:
>> Some of the debugfs files require access to the registers that are
>> not accessible to the VFs. Don't expose those files on VF drivers.
>>
>> Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
>> Cc: Marcin Bernatowicz <marcin.bernatowicz@linux.intel.com>
>> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
>> ---
>> v2: avoid "privileged" word, make it clear it's about VF/PF (Lucas)
>>     add hint for developers where to add new files (Lucas)
>> ---
>>  drivers/gpu/drm/xe/xe_gt_debugfs.c | 30 ++++++++++++++++++++++--------
>>  1 file changed, 22 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_gt_debugfs.c b/drivers/gpu/drm/xe/xe_gt_debugfs.c
>> index 2d63a69cbfa3..a88076e9cc7d 100644
>> --- a/drivers/gpu/drm/xe/xe_gt_debugfs.c
>> +++ b/drivers/gpu/drm/xe/xe_gt_debugfs.c
>> @@ -299,20 +299,20 @@ static int hwconfig(struct xe_gt *gt, struct drm_printer *p)
>>  	return 0;
>>  }
>>  
>> -static const struct drm_info_list debugfs_list[] = {
>> -	{"hw_engines", .show = xe_gt_debugfs_simple_show, .data = hw_engines},
>> +/*
>> + * only for GT debugfs files which can be safely used on the VF as well:
>> + * - without access to the GT privileged registers
>> + * - without access to the PF specific data
>> + */
>> +static const struct drm_info_list vf_safe_debugfs_list[] = {
>>  	{"force_reset", .show = xe_gt_debugfs_simple_show, .data = force_reset},
>>  	{"force_reset_sync", .show = xe_gt_debugfs_simple_show, .data = force_reset_sync},
> 
> Probably don't expose the reset ones to VF either.

why not? from commit 459777724d30 ("drm/xe/vf: Don't try to trigger a
full GT reset if VF") we just use H2G action VF_RESET(0x5507) to
exercise the reset flow as applicable method for the VF