Yuanyuan Zhao 0a4c76357e hv: hide mwait from guest. ... 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>		2022-11-04 18:55:52 +08:00
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x86/asm	hv: hide mwait from guest.	2022-11-04 18:55:52 +08:00