ppcexec: Emulate PowerPC sleep on MSR POW#186
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xnu-123.5 and similar vintage kernls enter the PowerPC 750 powersave mode when the scheduler has no runnable work. `machine_idle_ppc` selects HID0 doze or nap, records a nap timestamp, then executes mtmsr with MSR[POW] set. It stays in a loop there (in case the power saving had no effect immediately) - it expects execution to resume at the `machine_idle_ret` label (when an interrupt occurs), which ends up returning from the function. We model this state explicitly: - When mtmsr sets MSR[POW] with the HID0 doze/nap/sleep flags, set a new EXEF_SLEEP flag. - When EXEF_SLEEP is set, keep processing host events without advancing the guest PC. Towards getting the 10.0 public beta to boot (dingusdev#154) - before this we would enter the DPPC debugger shortly after this instruction (due to a bogus MSR LE flag eventually being set). Now we make more progress and end up in a "Still waiting for root device" loop (presumably something at the ATA layer)
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xnu-123.5 and similar vintage kernls enter the PowerPC 750 power save mode when the scheduler has no runnable work.
machine_idle_ppcselects HID0 doze or nap, records a nap timestamp, then executesmtmsrwithMSR[POW]set. It stays in a loop there (in case the power saving had no effect immediately) - it expects execution to resume at themachine_idle_retlabel (when an interrupt occurs), which ends up returning from the function.We model this state explicitly:
mtmsrsetsMSR[POW]with theHID0doze/nap/sleep flags, set a newEXEF_SLEEPflag.EXEF_SLEEPis set, keep processing host events without advancing the guest PC.Towards getting the 10.0 public beta to boot (#154) - before this we would enter the DPPC debugger shortly after this instruction (due to a bogus MSR LE flag eventually being set). Now we make more progress and end up in a "Still waiting for root device" loop (presumably something at the ATA layer)