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0a4c76357e
When CPU support MONITOR/MWAIT, OS prefer to use it enter
deeper C-state.
Now ACRN pass through MONITOR/MWAIT to guest.
For vCPUs (ie vCPU A and vCPU B) share a pCPU, if vCPU A uses MWait to enter C state,
vCPU B could run only after the time slice of vCPU A is expired. This time slice of
vCPU A is gone to waste.
For Local APIC pass-through (used for RTVM), the guest pay more attention to
timeliness than power saving.
So this patch hides MONITOR/MWAIT by:
1. Clear vCPUID.05H, vCPUID.01H:ECX.[bit 3] and
MSR_IA32_MISC_ENABLE_MONITOR_ENA to tell the guest VM's vCPU
does not support MONITOR/MAIT.
2. Enable MSR_IA32_MISC_ENABLE_MONITOR_ENA bit for
MSR_IA32_MISC_ENABLE inject 'GP'.
3. Trap instruction 'MONITOR' and 'MWAIT' and inject 'UD'.
4. Clear vCPUID.07H:ECX.[bit 5] to hide 'UMONITOR/UMWAIT'.
5. Clear "enable user wait and pause" VM-execution control, so
UMONITOR/MWAIT causes an 'UD'.
Tracked-On: #8253
Signed-off-by: Yuanyuan Zhao <yuanyuan.zhao@linux.intel.com>
Reviewed-by: Fei Li <fei1.li@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/