On 18/12/2019 11:27, Alexey Budankov wrote:
> Open access to i915_perf monitoring for CAP_SYS_PERFMON privileged
> processes. For backward compatibility reasons access to i915_perf
> subsystem remains open for CAP_SYS_ADMIN privileged processes but
> CAP_SYS_ADMIN usage for secure i915_perf monitoring is discouraged
> with respect to CAP_SYS_PERFMON capability.
>
> Signed-off-by: Alexey Budankov <[email protected]>
Acked-by: Lionel Landwerlin <[email protected]>
> ---
> drivers/gpu/drm/i915/i915_perf.c | 13 ++++++-------
> 1 file changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
> index e42b86827d6b..e2697f8d04de 100644
> --- a/drivers/gpu/drm/i915/i915_perf.c
> +++ b/drivers/gpu/drm/i915/i915_perf.c
> @@ -2748,10 +2748,10 @@ i915_perf_open_ioctl_locked(struct drm_i915_private *dev_priv,
> /* Similar to perf's kernel.perf_paranoid_cpu sysctl option
> * we check a dev.i915.perf_stream_paranoid sysctl option
> * to determine if it's ok to access system wide OA counters
> - * without CAP_SYS_ADMIN privileges.
> + * without CAP_SYS_PERFMON or CAP_SYS_ADMIN privileges.
> */
> if (privileged_op &&
> - i915_perf_stream_paranoid && !capable(CAP_SYS_ADMIN)) {
> + i915_perf_stream_paranoid && !perfmon_capable()) {
> DRM_DEBUG("Insufficient privileges to open system-wide i915 perf stream\n");
> ret = -EACCES;
> goto err_ctx;
> @@ -2939,9 +2939,8 @@ static int read_properties_unlocked(struct drm_i915_private *dev_priv,
> } else
> oa_freq_hz = 0;
>
> - if (oa_freq_hz > i915_oa_max_sample_rate &&
> - !capable(CAP_SYS_ADMIN)) {
> - DRM_DEBUG("OA exponent would exceed the max sampling frequency (sysctl dev.i915.oa_max_sample_rate) %uHz without root privileges\n",
> + if (oa_freq_hz > i915_oa_max_sample_rate && !perfmon_capable()) {
> + DRM_DEBUG("OA exponent would exceed the max sampling frequency (sysctl dev.i915.oa_max_sample_rate) %uHz without CAP_SYS_PERFMON or CAP_SYS_ADMIN privileges\n",
> i915_oa_max_sample_rate);
> return -EACCES;
> }
> @@ -3328,7 +3327,7 @@ int i915_perf_add_config_ioctl(struct drm_device *dev, void *data,
> return -EINVAL;
> }
>
> - if (i915_perf_stream_paranoid && !capable(CAP_SYS_ADMIN)) {
> + if (i915_perf_stream_paranoid && !perfmon_capable()) {
> DRM_DEBUG("Insufficient privileges to add i915 OA config\n");
> return -EACCES;
> }
> @@ -3474,7 +3473,7 @@ int i915_perf_remove_config_ioctl(struct drm_device *dev, void *data,
> return -ENOTSUPP;
> }
>
> - if (i915_perf_stream_paranoid && !capable(CAP_SYS_ADMIN)) {
> + if (i915_perf_stream_paranoid && !perfmon_capable()) {
> DRM_DEBUG("Insufficient privileges to remove i915 OA config\n");
> return -EACCES;
> }