This patch is to eliminate kernel error msgs:
'ACPI Error: AE_NOT_FOUND, Evaluating _PSS'
This is caused by missing of _PSS table in guest ACPI. It would
happen when pstate is not injected to the guest.
Kernel ACPI pstate driver first probes
_PPC(performance capabilites) and _PCT(performance control)
in ACPI. If they exist, then it loads the _PSS(performance state).
If _PPC/_PCT are presented while _PSS is missing, it prints
the error msg.
In acrn-dm, _PPC/_PCT are hard-coded to all vCPUs, while _PSS
are constructed with the pCPUs' pstate data. This is base on
assumption that all VMs can have pstate.
Now the pstate is given to VM only when the VM is not sharing
any CPU(and no RTVM is setup in the scenario).
When the VM doesn't have pstate, the hypercall will return px_cnt=0,
and the _PSS is not constructed. In this case, _PPC/PCT should not
be injected, too.
Tracked-On: #6848
Signed-off-by: Zhou, Wu <wu.zhou@intel.com>
Acked-by: Anthony Xu <anthony.xu@intel.com>
Acked-by: Eddie Dong <eddie.dong@Intel.com>
7d0c05f3ff