FYI, we noticed the following commit: commit: 1e90bfdae094e1f0f1a57300362413e94ef9eaa5 ("ACPI throttling: Disable the MSR T-state if enabled after resumed") url: https://github.com/0day-ci/linux/commits/Chen-Yu/Disable-the-MSR-T-state-... base: https://git.kernel.org/cgit/linux/kernel/git/rafael/linux-pm.git linux-next in testcase: pm-qa with following parameters: test: cpuhotplug on test machine: qemu-system-x86_64 -enable-kvm -cpu host -smp 4 -m 5G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): [ 24.005507] kvm-clock: cpu 1, msr 1:7ff52041, secondary cpu clock [ 24.012540] masked ExtINT on CPU#1 [ 24.037771] KVM setup async PF for cpu 1 [ 24.044756] kvm-stealtime: cpu 1, msr 17fc8d980 [ 24.053225] ACPI: HARDWARE addr space,NOT supported yet [ 24.105279] cpuhotplug_02.1/cpu1: checking cpu1 is online... Ok [ 24.105289] To reproduce: git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git cd lkp-tests bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email Thanks, Xiaolong