On 7/23/21 11:16 AM, Pratik R. Sampat wrote:
> Adds a generic interface to represent the energy and frequency related
> PAPR attributes on the system using the new H_CALL
> "H_GET_ENERGY_SCALE_INFO".
>
> H_GET_EM_PARMS H_CALL was previously responsible for exporting this
> information in the lparcfg, however the H_GET_EM_PARMS H_CALL
> will be deprecated P10 onwards.
>
> The H_GET_ENERGY_SCALE_INFO H_CALL is of the following call format:
> hcall(
> uint64 H_GET_ENERGY_SCALE_INFO, // Get energy scale info
> uint64 flags, // Per the flag request
> uint64 firstAttributeId,// The attribute id
> uint64 bufferAddress, // Guest physical address of the output buffer
> uint64 bufferSize // The size in bytes of the output buffer
> );
>
> This H_CALL can query either all the attributes at once with
> firstAttributeId = 0, flags = 0 as well as query only one attribute
> at a time with firstAttributeId = id, flags = 1.
>
> The output buffer consists of the following
> 1. number of attributes - 8 bytes
> 2. array offset to the data location - 8 bytes
> 3. version info - 1 byte
> 4. A data array of size num attributes, which contains the following:
> a. attribute ID - 8 bytes
> b. attribute value in number - 8 bytes
> c. attribute name in string - 64 bytes
> d. attribute value in string - 64 bytes
>
> The new H_CALL exports information in direct string value format, hence
> a new interface has been introduced in
> /sys/firmware/papr/energy_scale_info to export this information to
> userspace in an extensible pass-through format.
>
> The H_CALL returns the name, numeric value and string value (if exists)
>
> The format of exposing the sysfs information is as follows:
> /sys/firmware/papr/energy_scale_info/
>|-- /
> |-- desc
> |-- value
> |-- value_desc (if exists)
>|-- /
> |-- desc
> |-- value
> |-- value_desc (if exists)
> ...
>
> The energy information that is exported is useful for userspace tools
> such as powerpc-utils. Currently these tools infer the
> "power_mode_data" value in the lparcfg, which in turn is obtained from
> the to be deprecated H_GET_EM_PARMS H_CALL.
> On future platforms, such userspace utilities will have to look at the
> data returned from the new H_CALL being populated in this new sysfs
> interface and report this information directly without the need of
> interpretation.
>
Patch looks good to me.
Reviewed-by: Kajol Jain
Thanks,
Kajol Jain
> Signed-off-by: Pratik R. Sampat
> Reviewed-by: Gautham R. Shenoy
> ---
> .../sysfs-firmware-papr-energy-scale-info | 26 ++
> arch/powerpc/include/asm/hvcall.h | 24 +-
> arch/powerpc/kvm/trace_hv.h | 1 +
> arch/powerpc/platforms/pseries/Makefile | 3 +-
> .../pseries/papr_platform_attributes.c| 312 ++
> 5 files changed, 364 insertions(+), 2 deletions(-)
> create mode 100644
> Documentation/ABI/testing/sysfs-firmware-papr-energy-scale-info
> create mode 100644 arch/powerpc/platforms/pseries/papr_platform_attributes.c
>
> diff --git a/Documentation/ABI/testing/sysfs-firmware-papr-energy-scale-info
> b/Documentation/ABI/testing/sysfs-firmware-papr-energy-scale-info
> new file mode 100644
> index ..139a576c7c9d
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-firmware-papr-energy-scale-info
> @@ -0,0 +1,26 @@
> +What:/sys/firmware/papr/energy_scale_info
> +Date:June 2021
> +Contact: Linux for PowerPC mailing list
> +Description: Directory hosting a set of platform attributes like
> + energy/frequency on Linux running as a PAPR guest.
> +
> + Each file in a directory contains a platform
> + attribute hierarchy pertaining to performance/
> + energy-savings mode and processor frequency.
> +
> +What:/sys/firmware/papr/energy_scale_info/
> + /sys/firmware/papr/energy_scale_info//desc
> + /sys/firmware/papr/energy_scale_info//value
> + /sys/firmware/papr/energy_scale_info//value_desc
> +Date:June 2021
> +Contact: Linux for PowerPC mailing list
> +Description: Energy, frequency attributes directory for POWERVM servers
> +
> + This directory provides energy, frequency, folding information.
> It
> + contains below sysfs attributes:
> +
> + - desc: String description of the attribute
> +
> + - value: Numeric value of attribute
> +
> + - value_desc: String value of attribute
> diff --git a/arch/powerpc/include/asm/hvcall.h
> b/arch/powerpc/include/asm/hvcall.h
> index e3b29eda8074..c91714ea6719 100644
> --- a/arch/powerpc/include/asm/hvcall.h
> +++ b/arch/powerpc/include/asm/hvcall.h
> @@ -316,7 +316,8 @@
> #define H_SCM_PERFORMANCE_STATS 0x418
> #define H_RPT_INVALIDATE 0x448
> #define H_SCM_FLUSH 0x44C
