Re: [PATCH] accel/ivpu: Add support for getting and setting command queue priority

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Missing CAP_SYS_NICE or DRM_MASTER check for elevated job priorities (REALTIME / FOCUS), allowing unprivileged users to monopolize the NPU.
--

commit 57cf0d7005a7761ad6193ea568802164b7fac6db
Author: Andrzej Kacprowski <andrzej.kacprowski@linux.intel.com>

accel/ivpu: Add support for getting and setting command queue priority

This commit adds a new DRM_IVPU_PARAM_CMDQ_PRIORITY parameter to query and
update the scheduling priority of an existing command queue. The priority
can be changed on a queue that already has pending jobs, propagating the
change to firmware in hardware scheduling mode.

> diff --git a/drivers/accel/ivpu/ivpu_job.c b/drivers/accel/ivpu/ivpu_job.c
> index ebb2c865b09a0..b3de5dd29d1e8 100644
> --- a/drivers/accel/ivpu/ivpu_job.c
> +++ b/drivers/accel/ivpu/ivpu_job.c

[ ... ]

> @@ -1127,6 +1132,86 @@ int ivpu_cmdq_destroy_ioctl(struct drm_device *dev, void *data, struct drm_file
>  	return ret;
>  }
>  
> +static int ivpu_cmdq_priority_args_check(struct ivpu_device *vdev, u32 cmdq_id, u64 priority)
> +{
> +	if (!ivpu_is_capable(vdev, DRM_IVPU_CAP_CMDQ_SET_PRIORITY)) {
> +		ivpu_dbg(vdev, IOCTL, "Command queue priority not supported\n");
> +		return -ENODEV;
> +	}
> +
> +	if (cmdq_id < IVPU_CMDQ_MIN_ID || cmdq_id > IVPU_CMDQ_MAX_ID) {
> +		ivpu_dbg(vdev, IOCTL, "Invalid command queue ID %u\n", cmdq_id);
> +		return -EINVAL;
> +	}
> +
> +	if (priority > DRM_IVPU_JOB_PRIORITY_REALTIME)
> +		return -EINVAL;

[Severity: High]
This is a pre-existing issue, but is there a missing capability check for
elevated priorities here?

An unprivileged user who opens the NPU device can call the IVPU_SET_PARAM
ioctl with DRM_IVPU_PARAM_CMDQ_PRIORITY and set the priority to
DRM_IVPU_JOB_PRIORITY_REALTIME. Without a CAP_SYS_NICE or DRM_MASTER check,
could a malicious or buggy application elevate its command queue priority to
monopolize the hardware and starve other processes?

I notice this same behavior appears to be pre-existing in
ivpu_cmdq_create_ioctl() as well, where queues can be created with realtime
priority by any user. Should these priority levels be restricted?

> +
> +	return 0;
> +}
> +
> +int ivpu_cmdq_get_priority(struct ivpu_file_priv *file_priv, u32 cmdq_id, u64 *priority)
> +{

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260831121617.395523-1-andrzej.kacprowski@linux.intel.com?part=1