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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>
ACRN Device Model ################# Introduction ============ The ACRN Device Model provides **device sharing** capabilities between the Service OS and Guest OSs. It is a component that is used in conjunction with the `ACRN Hypervisor`_ and this is installed within the Service OS. You can find out more about Project ACRN on the `Project ACRN documentation`_ website. .. _`ACRN Hypervisor`: https://github.com/projectacrn/acrn-hypervisor .. _`Project ACRN documentation`: https://projectacrn.github.io/