Re: [PATCH v5 2/8] platform/x86/amd/pmf: store BIOS output values for user-space metrics via util IOCTL

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

On Thu, 21 May 2026, Shyam Sundar S K wrote:

> Add a bios_output[] to amd_pmf_dev struct and store the latest values for
> BIOS output policies when applying PMF policies. This enables the AMD PMF
> util layer to expose these BIOS outputs alongside selected thermal and
> power metrics to user space via /dev/amdpmf_interface and a new IOCTL,
> supporting real-time monitoring tools such as SystemDeck.
> 
> Co-developed-by: Sanket Goswami <Sanket.Goswami@amd.com>
> Signed-off-by: Sanket Goswami <Sanket.Goswami@amd.com>
> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
> ---
>  drivers/platform/x86/amd/pmf/pmf.h    |  2 ++
>  drivers/platform/x86/amd/pmf/tee-if.c | 11 ++++++++++-
>  include/uapi/linux/amd-pmf.h          |  1 +
>  3 files changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/amd/pmf/pmf.h b/drivers/platform/x86/amd/pmf/pmf.h
> index 6f61076a9386..ffe74ebc46f8 100644
> --- a/drivers/platform/x86/amd/pmf/pmf.h
> +++ b/drivers/platform/x86/amd/pmf/pmf.h
> @@ -130,6 +130,7 @@ struct cookie_header {
>  #define GET_CMD		true
>  
>  #define METRICS_TABLE_ID	7
> +#define BIOS_OUTPUT_MAX		10
>  
>  typedef void (*apmf_event_handler_t)(acpi_handle handle, u32 event, void *data);
>  
> @@ -442,6 +443,7 @@ struct amd_pmf_dev {
>  	struct pmf_cbi_ring_buffer cbi_buf;
>  	struct mutex cbi_mutex;		     /* Protects ring buffer access */
>  	struct mutex metrics_mutex;
> +	u32 bios_output[BIOS_OUTPUT_MAX];
>  };
>  
>  struct apmf_sps_prop_granular_v2 {
> diff --git a/drivers/platform/x86/amd/pmf/tee-if.c b/drivers/platform/x86/amd/pmf/tee-if.c
> index 7ccd93f506b2..be8062c6691d 100644
> --- a/drivers/platform/x86/amd/pmf/tee-if.c
> +++ b/drivers/platform/x86/amd/pmf/tee-if.c
> @@ -8,7 +8,9 @@
>   * Author: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
>   */
>  
> +#include <linux/array_size.h>
>  #include <linux/debugfs.h>
> +#include <linux/dev_printk.h>
>  #include <linux/tee_drv.h>
>  #include <linux/uuid.h>
>  #include "pmf.h"
> @@ -98,10 +100,17 @@ static int amd_pmf_get_bios_output_idx(u32 action_idx)
>  static void amd_pmf_update_bios_output(struct amd_pmf_dev *pdev, struct ta_pmf_action *action)
>  {
>  	u32 bios_idx;
> +	int ret;
>  
>  	bios_idx = amd_pmf_get_bios_output_idx(action->action_index);
> +	if (bios_idx >= ARRAY_SIZE(pdev->bios_output)) {

amd_pmf_get_bios_output_idx() can return -EINVAL but it is never checked 
(a pre-existing problem) and value is directly going to an unsigned type 
(noted by sashiko).

> +		dev_warn(pdev->dev, "BIOS output index %u out of bounds\n", bios_idx);
> +		return;
> +	}
>  
> -	amd_pmf_smartpc_apply_bios_output(pdev, action->value, BIT(bios_idx), bios_idx);
> +	ret = amd_pmf_smartpc_apply_bios_output(pdev, action->value, BIT(bios_idx), bios_idx);
> +	if (!ret)
> +		pdev->bios_output[bios_idx] = action->value;
>  }
>  
>  static void amd_pmf_apply_policies(struct amd_pmf_dev *dev, struct ta_pmf_enact_result *out)
> diff --git a/include/uapi/linux/amd-pmf.h b/include/uapi/linux/amd-pmf.h
> index c7099e7f463f..d29a4abe1145 100644
> --- a/include/uapi/linux/amd-pmf.h
> +++ b/include/uapi/linux/amd-pmf.h
> @@ -55,6 +55,7 @@ struct amd_pmf_info {
>  
>  	/* BIOS parameters */
>  	__u32 bios_input[AMD_PMF_BIOS_PARAMS_MAX];
> +	__u32 bios_output[AMD_PMF_BIOS_PARAMS_MAX];
>  };
>  
>  #endif /* _UAPI_LINUX_AMD_PMF_H */
> 

-- 
 i.