drm/xe: Add max engine priority to xe query

Intel Vulkan driver needs to know what is the maximum priority to fill
a device info struct for applications.

Right now we getting this information by creating a engine and setting
priorities from min to high to know what is the maximum priority for
running process but this leads to info messages to be printed to
dmesg:

xe 0000:03:00.0: [drm] Ioctl argument check failed at drivers/gpu/drm/xe/xe_engine.c:178: value == DRM_SCHED_PRIORITY_HIGH && !capable(CAP_SYS_NICE)

It does not cause any harm but when executing a test suite like
crucible it causes thousands of those messages to be printed.

So here adding one more property to drm_xe_query_config to fetch the
max engine priority.

Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/xe/xe_engine.c

@@ -169,14 +169,20 @@ struct xe_engine *xe_engine_lookup(struct xe_file *xef, u32 id)
 	return e;
 }
 
+enum xe_engine_priority
+xe_engine_device_get_max_priority(struct xe_device *xe)
+{
+	return capable(CAP_SYS_NICE) ? XE_ENGINE_PRIORITY_HIGH :
+			               XE_ENGINE_PRIORITY_NORMAL;
+}
+
 static int engine_set_priority(struct xe_device *xe, struct xe_engine *e,
 			       u64 value, bool create)
 {
 	if (XE_IOCTL_ERR(xe, value > XE_ENGINE_PRIORITY_HIGH))
 		return -EINVAL;
 
-	if (XE_IOCTL_ERR(xe, value == XE_ENGINE_PRIORITY_HIGH &&
-			 !capable(CAP_SYS_NICE)))
+	if (XE_IOCTL_ERR(xe, value > xe_engine_device_get_max_priority(xe)))
 		return -EPERM;
 
 	return e->ops->set_priority(e, value);

drivers/gpu/drm/xe/xe_engine.h

@@ -54,5 +54,6 @@ int xe_engine_set_property_ioctl(struct drm_device *dev, void *data,
 				 struct drm_file *file);
 int xe_engine_get_property_ioctl(struct drm_device *dev, void *data,
 				 struct drm_file *file);
+enum xe_engine_priority xe_engine_device_get_max_priority(struct xe_device *xe);
 
 #endif

drivers/gpu/drm/xe/xe_query.c

@@ -12,6 +12,7 @@
 
 #include "xe_bo.h"
 #include "xe_device.h"
+#include "xe_engine.h"
 #include "xe_ggtt.h"
 #include "xe_gt.h"
 #include "xe_guc_hwconfig.h"
@@ -194,6 +195,8 @@ static int query_config(struct xe_device *xe, struct drm_xe_device_query *query)
 	config->info[XE_QUERY_CONFIG_GT_COUNT] = xe->info.tile_count;
 	config->info[XE_QUERY_CONFIG_MEM_REGION_COUNT] =
 		hweight_long(xe->info.mem_region_mask);
+	config->info[XE_QUERY_CONFIG_MAX_ENGINE_PRIORITY] =
+		xe_engine_device_get_max_priority(xe);
 
 	if (copy_to_user(query_ptr, config, size)) {
 		kfree(config);

include/uapi/drm/xe_drm.h

@@ -184,7 +184,8 @@ struct drm_xe_query_config {
 #define XE_QUERY_CONFIG_VA_BITS			3
 #define XE_QUERY_CONFIG_GT_COUNT		4
 #define XE_QUERY_CONFIG_MEM_REGION_COUNT	5
-#define XE_QUERY_CONFIG_NUM_PARAM		XE_QUERY_CONFIG_MEM_REGION_COUNT + 1
+#define XE_QUERY_CONFIG_MAX_ENGINE_PRIORITY	6
+#define XE_QUERY_CONFIG_NUM_PARAM		XE_QUERY_CONFIG_MAX_ENGINE_PRIORITY + 1
 	__u64 info[];
 };