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The design of ACRN CPU performance management is to let hardware
do the autonomous frequency selection(or set to a fixed value),
and remove guest's ability to control CPU frequency.
This patch is to remove guest's ability to control CPU frequency by
removing the guests' HWP/EIST CPUIDs and blocking the related MSR
accesses. Including:
- Remove CPUID.06H:EAX[7..11] (HWP)
- Remove CPUID.01H:ECX[7] (EIST)
- Inject #GP(0) upon accesses to MSR_IA32_PM_ENABLE,
MSR_IA32_HWP_CAPABILITIES, MSR_IA32_HWP_REQUEST,
MSR_IA32_HWP_STATUS, MSR_IA32_HWP_INTERRUPT,
MSR_IA32_HWP_REQUEST_PKG
- Emulate MSR_IA32_PERF_CTL. Value written to MSR_IA32_PERF_CTL
is just stored for reading. This is like how the native
environment would behavior when EIST is disabled from BIOS.
- Emulate MSR_IA32_PERF_STATUS by filling it with base frequency
state. This is consistent with Windows, which displays current
frequency as base frequency when running in VM.
- Hide the IA32_MISC_ENABLE bit 16 (EIST enable) from guests.
This bit is dependent to CPUID.01H:ECX[7] according to SDM.
- Remove CPID.06H:ECX[0] (hardware coordination feedback)
- Inject #GP(0) upon accesses to IA32_MPERF, IA32_APERF
Also DM do not need to generate _PSS/_PPC for post-launched VMs
anymore. This is done by letting hypercall HC_PM_GET_CPU_STATE sub
command ACRN_PMCMD_GET_PX_CNT and ACRN_PMCMD_GET_PX_DATA return (-1).
Tracked-On: #8168
Signed-off-by: Wu Zhou <wu.zhou@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
ACRN Hypervisor ############### The open source `Project ACRN`_ defines a device hypervisor reference stack and an architecture for running multiple software subsystems, managed securely, on a consolidated system by means of a virtual machine manager. It also defines a reference framework implementation for virtual device emulation, called the "ACRN Device Model". The ACRN Hypervisor is a Type 1 reference hypervisor stack, running directly on the bare-metal hardware, and is suitable for a variety of IoT and embedded device solutions. The ACRN hypervisor addresses the gap that currently exists between datacenter hypervisors, and hard partitioning hypervisors. The ACRN hypervisor architecture partitions the system into different functional domains, with carefully selected guest OS sharing optimizations for IoT and embedded devices. You can find out more about Project ACRN on the `Project ACRN documentation`_ website. .. _`Project ACRN`: https://projectacrn.org .. _`ACRN Hypervisor`: https://github.com/projectacrn/acrn-hypervisor .. _`Project ACRN documentation`: https://projectacrn.github.io/