[PATCH i-g-t,v2 4/6] lib/intel_compute: Allow the user to provide a custom compute kernel

[Zbigniew Kempczyński]

On Mon, Feb 24, 2025 at 03:46:12PM +0100, Francois Dugast wrote:
> Allow the user to provide a custom compute kernel which will be used
> instead of the default compute square one. This custom kernel _must_
> fulfill requirements specified in the user_execenv::kernel doc. IGT
> does not provide a complete runtime which can run generic kernels.
> 
> Allowing custom compute kernels gives us the possibility to leverage
> the existing lib/intel_compute infrastructure to test corner cases.
> More complex KMD tests will require simple specific compute kernels.
> For example this one can trigger a page fault at 0x10000 from the
> compute kernel context, so that we run other checks in KMD, all from
> IGT:
> 
>     __kernel void square(__global float* input,
>                          __global float* output,
>                          const unsigned int count) {
>         int i = get_global_id(0);
>         const __global uint* addr = 0x10000;
>         output[i] = *addr;
>     }
> 
> v2: Improve documentation and commit message
> 
> Signed-off-by: Francois Dugast <francois.dugast at intel.com>

Please drop versioning during merge, it is not needed. With that:

Reviewed-by: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>

--
Zbigniew

> ---
>  lib/intel_compute.c | 26 ++++++++++++++++++--------
>  lib/intel_compute.h | 14 ++++++++++++++
>  2 files changed, 32 insertions(+), 8 deletions(-)
> 
> diff --git a/lib/intel_compute.c b/lib/intel_compute.c
> index cad932c24..04fb83321 100644
> --- a/lib/intel_compute.c
> +++ b/lib/intel_compute.c
> @@ -1778,6 +1778,8 @@ static bool __run_intel_compute_kernel(int fd,
>  	unsigned int batch;
>  	const struct intel_compute_kernels *kernels = intel_compute_square_kernels;
>  	enum intel_driver driver = get_intel_driver(fd);
> +	const unsigned char *kernel;
> +	unsigned int kernel_size;
>  
>  	for (batch = 0; batch < ARRAY_SIZE(intel_compute_batches); batch++) {
>  		if (ip_ver == intel_compute_batches[batch].ip_ver)
> @@ -1795,16 +1797,24 @@ static bool __run_intel_compute_kernel(int fd,
>  		return false;
>  	}
>  
> -	while (kernels->kernel) {
> -		if (ip_ver == kernels->ip_ver)
> -			break;
> -		kernels++;
> +	/* If the user provides a kernel, use it */
> +	if (user && user->kernel) {
> +		kernel = user->kernel;
> +		kernel_size = user->kernel_size;
> +	} else {
> +		while (kernels->kernel) {
> +			if (ip_ver == kernels->ip_ver)
> +				break;
> +			kernels++;
> +		}
> +		if (!kernels->kernel)
> +			return false;
> +		kernel = kernels->kernel;
> +		kernel_size = kernels->size;
>  	}
> -	if (!kernels->kernel)
> -		return false;
>  
> -	intel_compute_batches[batch].compute_exec(fd, kernels->kernel,
> -						  kernels->size, eci, user);
> +	intel_compute_batches[batch].compute_exec(fd, kernel,
> +						  kernel_size, eci, user);
>  
>  	return true;
>  }
> diff --git a/lib/intel_compute.h b/lib/intel_compute.h
> index 62e2422c4..3f6d0bb1d 100644
> --- a/lib/intel_compute.h
> +++ b/lib/intel_compute.h
> @@ -39,6 +39,20 @@ struct intel_compute_kernels {
>  struct user_execenv {
>  	/** @vm: use this VM if provided, otherwise create one */
>  	uint32_t vm;
> +	/**
> +	 * @kernel: use this custom kernel if provided, otherwise use a default square kernel
> +	 *
> +	 * Custom kernel execution in lib/intel_compute has strong limitations, it does not
> +	 * allow running any custom kernel. "count" is the size of the input and output arrays
> +	 * and the provided kernel must have the following prototype:
> +	 *
> +	 *    __kernel void square(__global float* input,
> +	 *                         __global float* output,
> +	 *                         const unsigned int count)
> +	 */
> +	const unsigned char *kernel;
> +	/** @kernel_size: size of the custom kernel, if provided */
> +	unsigned int kernel_size;
>  };
>  
>  extern const struct intel_compute_kernels intel_compute_square_kernels[];
> -- 
> 2.43.0
>