diff options
| author | Pratik R. Sampat <psampat@linux.ibm.com> | 2022-02-17 16:23:20 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2022-03-08 00:05:00 +1100 |
| commit | 3c14b73454cf9f6e2146443fdfbdfb912c0efed3 (patch) | |
| tree | 5c29ed10af89390574941a6a3e7579a0e7682eb5 /arch/powerpc/kvm | |
| parent | cc15ff3275694fedc33cd3d53212a43eec7aa0bc (diff) | |
powerpc/pseries: Interface to represent PAPR firmware attributes
Adds a syscall 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
);
As specified in PAPR+ v2.11, section 14.14.3.
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 so that the firmware can add new values without the need for
the kernel to be changed.
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/
|-- <id>/
|-- desc
|-- value
|-- value_desc (if exists)
|-- <id>/
|-- 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.
Signed-off-by: Pratik R. Sampat <psampat@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220217105321.52941-2-psampat@linux.ibm.com
Diffstat (limited to 'arch/powerpc/kvm')
| -rw-r--r-- | arch/powerpc/kvm/trace_hv.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/trace_hv.h b/arch/powerpc/kvm/trace_hv.h index 830a126e095d..38cd0ed0a617 100644 --- a/arch/powerpc/kvm/trace_hv.h +++ b/arch/powerpc/kvm/trace_hv.h @@ -115,6 +115,7 @@ {H_VASI_STATE, "H_VASI_STATE"}, \ {H_ENABLE_CRQ, "H_ENABLE_CRQ"}, \ {H_GET_EM_PARMS, "H_GET_EM_PARMS"}, \ + {H_GET_ENERGY_SCALE_INFO, "H_GET_ENERGY_SCALE_INFO"}, \ {H_SET_MPP, "H_SET_MPP"}, \ {H_GET_MPP, "H_GET_MPP"}, \ {H_HOME_NODE_ASSOCIATIVITY, "H_HOME_NODE_ASSOCIATIVITY"}, \ |