[PATCH 23/24] drm/amdkfd: add pc sampling capability check

[Felix Kuehling]

On 2023-11-03 09:11, James Zhu wrote:
> From: David Yat Sin <david.yatsin at amd.com>
>
> Add pc sampling capability check.

This should be squashed into patch 2. Or if you want to keep it 
separate, put this patch before patch 2 and define AMDKFD_IOC_PC_SAMPLE 
with KFD_IOC_FLAG_PERFMON from the beginning.

Regards,
   Felix


>
> Signed-off-by: David Yat Sin <david.yatsin at amd.com>
> Signed-off-by: James Zhu <James.Zhu at amd.com>
> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 10 +++++++++-
>   drivers/gpu/drm/amd/amdkfd/kfd_priv.h    | 13 +++++++++++++
>   2 files changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> index b00390e451bf..5e47e374d824 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> @@ -3259,7 +3259,7 @@ static const struct amdkfd_ioctl_desc amdkfd_ioctls[] = {
>   			kfd_ioctl_set_debug_trap, 0),
>   
>   	AMDKFD_IOCTL_DEF(AMDKFD_IOC_PC_SAMPLE,
> -			kfd_ioctl_pc_sample, 0),
> +			kfd_ioctl_pc_sample, KFD_IOC_FLAG_PERFMON),
>   };
>   
>   #define AMDKFD_CORE_IOCTL_COUNT	ARRAY_SIZE(amdkfd_ioctls)
> @@ -3336,6 +3336,14 @@ static long kfd_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
>   		}
>   	}
>   
> +	/* PC Sampling Monitor */
> +	if (unlikely(ioctl->flags & KFD_IOC_FLAG_PERFMON)) {
> +		if (!capable(CAP_PERFMON) && !capable(CAP_SYS_ADMIN)) {
> +			retcode = -EACCES;
> +			goto err_i1;
> +		}
> +	}
> +
>   	if (cmd & (IOC_IN | IOC_OUT)) {
>   		if (asize <= sizeof(stack_kdata)) {
>   			kdata = stack_kdata;
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> index b7062033fda4..236d3de85153 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> @@ -144,6 +144,19 @@ enum kfd_ioctl_flags {
>   	 * we also allow ioctls with SYS_ADMIN capability.
>   	 */
>   	KFD_IOC_FLAG_CHECKPOINT_RESTORE = BIT(0),
> +
> +	/*
> +	 * @KFD_IOC_FLAG_PERFMON:
> +	 * Performance monitoring feature, GPU performance monitoring can allow users
> +	 * to gather some information about other processes. PC sampling can allow
> +	 * users to infer information about wavefronts from other processes that are
> +	 * running on the same CUs, such as which execution units they are using. As
> +	 * such, this type of performance monitoring should be protected and only
> +	 * available to users with sufficient capabilities: either CAP_PERFMON, or,
> +	 * for backwards compatibility, CAP_SYS_ADMIN.
> +	 */
> +
> +	KFD_IOC_FLAG_PERFMON = BIT(1),
>   };
>   /*
>    * Kernel module parameter to specify maximum number of supported queues per