Re: [PATCH] drm/xe/uapi: Add DRM_XE_QUERY_CONFIG_FLAG_HAS_DIS_NULL_QUERY

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Wed, Jun 25, 2025 at 03:28:05PM +0530, Nitin Gote wrote:
> Add the DRM_XE_QUERY_CONFIG_FLAG_HAS_DIS_NULL_QUERY device query flag
> which indicates whether a device supports DIS_NULL_QUERY (Disable null
> anyhit shader query mechanism). The intent is for UMDs
> to use this query and opt-in DRM_XE_EXEC_QUEUE_DIS_NULL_QUERY flag
> to disable null query mechanism for anyhit shader by setting
> DIS_NULL_QUERY bit of RT_CTRL register for Xe2.
> 
> v2:
>    - Use xe_rtp_match_first_render_or_compute() api to check
>      render_or_compute. (Tejas)
>    - Validate args->flags (Tejas/Matthew)
>    - Add proper kernel-doc for both DRM_XE_EXEC_QUEUE_DIS_NULL_QUERY
>      and DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT. (Matthew)

Matt asked for full spelling of DISABLE, no?!

Also, where are the UMD patches/merge-requests for this? And their ack?

Thanks,
Rodrigo.

> 
> Signed-off-by: Nitin Gote <nitin.r.gote@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_exec_queue.c | 11 ++++++++++-
>  drivers/gpu/drm/xe/xe_query.c      |  3 ++-
>  include/uapi/drm/xe_drm.h          | 12 ++++++++++++
>  3 files changed, 24 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_exec_queue.c b/drivers/gpu/drm/xe/xe_exec_queue.c
> index fee22358cc09..ef8b49d2242a 100644
> --- a/drivers/gpu/drm/xe/xe_exec_queue.c
> +++ b/drivers/gpu/drm/xe/xe_exec_queue.c
> @@ -26,6 +26,9 @@
>  #include "xe_trace.h"
>  #include "xe_vm.h"
>  #include "xe_pxp.h"
> +#include "xe_gt_mcr.h"
> +#include "regs/xe_gt_regs.h"
> +#include "xe_rtp.h"
>  
>  enum xe_exec_queue_sched_prop {
>  	XE_EXEC_QUEUE_JOB_TIMEOUT = 0,
> @@ -597,7 +600,8 @@ int xe_exec_queue_create_ioctl(struct drm_device *dev, void *data,
>  	u32 len;
>  	int err;
>  
> -	if (XE_IOCTL_DBG(xe, args->flags & ~DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT) ||
> +	if (XE_IOCTL_DBG(xe, args->flags &
> +	    ~(DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT | DRM_XE_EXEC_QUEUE_DIS_NULL_QUERY)) ||
>  	    XE_IOCTL_DBG(xe, args->reserved[0] || args->reserved[1]))
>  		return -EINVAL;
>  
> @@ -693,6 +697,11 @@ int xe_exec_queue_create_ioctl(struct drm_device *dev, void *data,
>  		}
>  	}
>  
> +	if (((GRAPHICS_VER(xe) >= 20) && (GRAPHICS_VER(xe) < 30)) &&
> +	    (args->flags & DRM_XE_EXEC_QUEUE_DIS_NULL_QUERY) &&
> +	    xe_rtp_match_first_render_or_compute(q->gt, q->hwe))
> +		xe_gt_mcr_multicast_write(q->gt, RT_CTRL, DIS_NULL_QUERY);
> +
>  	q->xef = xe_file_get(xef);
>  
>  	/* user id alloc must always be last in ioctl to prevent UAF */
> diff --git a/drivers/gpu/drm/xe/xe_query.c b/drivers/gpu/drm/xe/xe_query.c
> index e8e1743dcb1e..c5002b8c9ac0 100644
> --- a/drivers/gpu/drm/xe/xe_query.c
> +++ b/drivers/gpu/drm/xe/xe_query.c
> @@ -344,7 +344,8 @@ static int query_config(struct xe_device *xe, struct drm_xe_device_query *query)
>  		config->info[DRM_XE_QUERY_CONFIG_FLAGS] |=
>  			DRM_XE_QUERY_CONFIG_FLAG_HAS_CPU_ADDR_MIRROR;
>  	config->info[DRM_XE_QUERY_CONFIG_FLAGS] |=
> -			DRM_XE_QUERY_CONFIG_FLAG_HAS_LOW_LATENCY;
> +			(DRM_XE_QUERY_CONFIG_FLAG_HAS_LOW_LATENCY |
> +			DRM_XE_QUERY_CONFIG_FLAG_HAS_DIS_NULL_QUERY);
>  	config->info[DRM_XE_QUERY_CONFIG_MIN_ALIGNMENT] =
>  		xe->info.vram_flags & XE_VRAM_FLAGS_NEED64K ? SZ_64K : SZ_4K;
>  	config->info[DRM_XE_QUERY_CONFIG_VA_BITS] = xe->info.va_bits;
> diff --git a/include/uapi/drm/xe_drm.h b/include/uapi/drm/xe_drm.h
> index 8e8bbdec8c5c..7c30e707346c 100644
> --- a/include/uapi/drm/xe_drm.h
> +++ b/include/uapi/drm/xe_drm.h
> @@ -397,6 +397,8 @@ struct drm_xe_query_mem_regions {
>   *      has low latency hint support
>   *    - %DRM_XE_QUERY_CONFIG_FLAG_HAS_CPU_ADDR_MIRROR - Flag is set if the
>   *      device has CPU address mirroring support
> + *    - %DRM_XE_QUERY_CONFIG_FLAG_HAS_DIS_NULL_QUERY - Flag is set if the
> + *      device has null query support for anyhit shader.
>   *  - %DRM_XE_QUERY_CONFIG_MIN_ALIGNMENT - Minimal memory alignment
>   *    required by this device, typically SZ_4K or SZ_64K
>   *  - %DRM_XE_QUERY_CONFIG_VA_BITS - Maximum bits of a virtual address
> @@ -415,6 +417,7 @@ struct drm_xe_query_config {
>  	#define DRM_XE_QUERY_CONFIG_FLAG_HAS_VRAM	(1 << 0)
>  	#define DRM_XE_QUERY_CONFIG_FLAG_HAS_LOW_LATENCY	(1 << 1)
>  	#define DRM_XE_QUERY_CONFIG_FLAG_HAS_CPU_ADDR_MIRROR	(1 << 2)
> +	#define DRM_XE_QUERY_CONFIG_FLAG_HAS_DIS_NULL_QUERY	(1 << 3)
>  #define DRM_XE_QUERY_CONFIG_MIN_ALIGNMENT		2
>  #define DRM_XE_QUERY_CONFIG_VA_BITS			3
>  #define DRM_XE_QUERY_CONFIG_MAX_EXEC_QUEUE_PRIORITY	4
> @@ -1270,7 +1273,16 @@ struct drm_xe_exec_queue_create {
>  	/** @vm_id: VM to use for this exec queue */
>  	__u32 vm_id;
>  
> +	/** DRM_XE_QUERY_CONFIG_FLAG_HAS_LOW_LATENCY - \
> +	 *	Flag is set if the device has low latency hint support
> +	 */
>  #define DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT	(1 << 0)
> +
> +	/** DRM_XE_EXEC_QUEUE_DIS_NULL_QUERY - \
> +	 *	flag is use to disable null query check for Anyhit shader
> +	 */
> +#define DRM_XE_EXEC_QUEUE_DIS_NULL_QUERY	(1 << 1)
> +
>  	/** @flags: flags to use for this exec queue */
>  	__u32 flags;
>  
> -- 
> 2.25.1
>