Re: Should -overcommit cpu-pm=on|off be converted to some machine sugar property?

[Paolo Bonzini]

It's implemented only for x86, but it is not architecture-dependent. For example on ARM you would implement it by mapping guest WFx to the host instructions.

Paolo

Il lun 19 dic 2022, 17:11 Philippe Mathieu-Daudé <philmd@linaro.org> ha scritto:

Hi Paolo,

I just noticed 'enable_cpu_pm' which seems architecture specific
option that ended into common code:

$ git grep -E 'cpu[_-]pm'
accel/tcg/user-exec-stub.c:5:bool enable_cpu_pm = false;
include/sysemu/sysemu.h:49:extern bool enable_cpu_pm;
Binary file pc-bios/skiboot.lid matches
qemu-options.hx:4196:    "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n"
qemu-options.hx:4199:    "                cpu-pm=on|off controls cpu
power management (default: off)\n",
qemu-options.hx:4204:``-overcommit cpu-pm=on|off``
qemu-options.hx:4214:    guest) can be enabled via ``cpu-pm=on``
(disabled by default). This
softmmu/globals.c:38:bool enable_cpu_pm;
softmmu/vl.c:350:            .name = "cpu-pm",
softmmu/vl.c:3440:                enable_cpu_pm =
qemu_opt_get_bool(opts, "cpu-pm", false);
target/i386/host-cpu.c:44:static void host_cpu_enable_cpu_pm(X86CPU *cpu)
target/i386/host-cpu.c:88:    if (cpu->max_features && enable_cpu_pm) {
target/i386/host-cpu.c:89:        host_cpu_enable_cpu_pm(cpu);
target/i386/kvm/kvm-cpu.c:43:        if (enable_cpu_pm &&
kvm_has_waitpkg()) {
target/i386/kvm/kvm.c:390:        if (enable_cpu_pm) {
target/i386/kvm/kvm.c:2576:    if (enable_cpu_pm) {

Do we want to maintain this as a generic property or
can it be deprecated / converted to a machine-specific one?

Thanks,

Phil.