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Date:   Tue, 11 Jul 2023 13:52:51 -0700
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Subject: Re: [PATCH v2 02/10] docs: ABI:
 sysfs-bus-event_source-devices-hv_gpci: Document processor_bus_topology sysfs
 interface file
Content-Language: en-US
To:     Kajol Jain <kjain@linux.ibm.com>, mpe@ellerman.id.au
Cc:     linuxppc-dev@lists.ozlabs.org, maddy@linux.ibm.com,
        atrajeev@linux.vnet.ibm.com, disgoel@linux.ibm.com,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20230710092717.55317-1-kjain@linux.ibm.com>
 <20230710092717.55317-3-kjain@linux.ibm.com>
From:   Randy Dunlap <rdunlap@infradead.org>
In-Reply-To: <20230710092717.55317-3-kjain@linux.ibm.com>
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Hi--

On 7/10/23 02:27, Kajol Jain wrote:
> Add details of the new hv-gpci interface file called
> "processor_bus_topology" in the ABI documentation.
> 
> Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
> ---
>  .../sysfs-bus-event_source-devices-hv_gpci    | 32 +++++++++++++++++++
>  1 file changed, 32 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
> index 12e2bf92783f..2eeeab9a20fa 100644
> --- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
> +++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
> @@ -80,3 +80,35 @@ Contact:	Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
>  Description:	read only
>  		This sysfs file exposes the cpumask which is designated to make
>  		HCALLs to retrieve hv-gpci pmu event counter data.
> +
> +What:		/sys/devices/hv_gpci/interface/processor_bus_topology
> +Date:		July 2023
> +Contact:	Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
> +Description:	admin read only
> +		This sysfs file exposes the system topology information by making HCALL
> +		H_GET_PERF_COUNTER_INFO. The HCALL is made with counter request value
> +		PROCESSOR_BUS_TOPOLOGY(0xD0).
> +
> +		* This sysfs file will be created only for power10 and above platforms.
> +
> +		* User needs root privileges to read data from this sysfs file.
> +
> +		* This sysfs file will be created, only when the HCALL returns "H_SUCESS",

		                                                                H_SUCCESS

> +		  "H_AUTHORITY" and "H_PARAMETER" as the return type.

		            s/and/or/

> +
> +		  HCALL with return error type "H_AUTHORITY", can be resolved during

		                             Drop the comma ^

> +		  runtime by setting "Enable Performance Information Collection" option.
> +
> +		* The end user reading this sysfs file must decode the content as per
> +		  underlying platform/firmware.
> +
> +		Possible error codes while reading this sysfs file:
> +
> +		* "-EPERM" : Partition is not permitted to retrieve performance information,
> +			    required to set "Enable Performance Information Collection" option.
> +
> +		* "-EIO" : Can't retrieve system information because of invalid buffer length/invalid address
> +			   or because of some hardware error. Refer getPerfCountInfo documentation for

			                                      Refer to

> +			   more information.
> +
> +		* "-EFBIG" : System information exceeds PAGE_SIZE.

-- 
~Randy