Hi guys, I'm confusing about the behavior of HLT instruction in VMX guest mode. I set "hlt exiting" bit to 0 in VMCS, and the vcpu didn't vmexit when execute HLT as expected. However, I used powertop/cpupower on host to watch the pcpu's c-states, it seems that the pcpu didn't enter C1/C1E state during this period. I searched the Intel spec vol-3, and only found that guest MWAIT won't entering a low-power sleep state under certain conditions(ch 25.3), but not mentioned HLT. My questions are 1) Does executing HLT instruction in guest-mode won't enter C1/C1E state ? 2) If it won't, then whether it would release the hardware resources shared with another hyper-thread ? Any suggestion would be greatly appreciated, thanks! -- Regards, Longpeng(Mike)
