Qemu emulator mac os cmu pdf mac os x#
Qemu emulator mac os cmu pdf Patch#

An interesting observation is that, on single-processor systems, MWAIT behaves very much like HLT: there is no other (V)CPU to trigger the monitoring hardware, and therefore MWAIT will only wake when a hardware interrupt is asserted. Once installed, the guest may be 'optimized' for power consumption and host CPU utilization by forcing it to fall back to a HLT-based idle thread.ДЄssuming the requirement to run a completely unmodified OS X guest install, we must support the default MONITOR/MWAIT idle thread in production, and attempt to alleviate host CPU utilization without the option of falling back to the HLT-based version.

Qemu emulator mac os cmu pdf mac os x#

This reduces host core utilization to single digits during guest idle times, since the guest VCPUs are removed from scheduling and execution on the host while halted.Дue to its simplicity and relative cleanliness, this combined approach may be a viable long term solution: NOP-based MONITOR/MWAIT emulation will allow booting Mac OS X from factory-default install media. Sudo rm /System/Library/Extensions/AppleIntelCPUPowerManagement.kext As before, these are short, non-power-saving NOP instructions, and therefore each VCPU will utilize 100% of the available cycles of a physical core on the host.ДЄs a workaround, it is possible to force Mac OS X to revert to a HLT-based idle thread by removing the default MONITOR/MWAIT one:

Qemu emulator mac os cmu pdf Patch#

My current stable patch against KVM replaces the handler for MONITOR and MWAIT with one that emulates the NOP instruction (i.e., skips the current MONITOR or MWAIT and re-enters VM guest mode execution from the immediately following instruction). The current handler for both instructions generates an Invalid Opcode exception, a behavior consistent with the non-support for the instructions advertised via CPUID. Emulate MONITOR/MWAIT as NOP As mentioned above, KVM currently requests that, among other instructions, MONITOR and MWAIT generate a VM exit and be handled in host (rather than guest) mode. This causes each guest VCPU to always utilize 100% of a host core, regardless of the actual level of guest activity.Дў.2.2. Configure and build using something like:ДЄccording to the spec (see V3, S25-3, pp25-8), under certain conditions (which happen to be met by the OS X idle thread), guest-mode MWAIT will always default to being treated as a NOP, never entering a low-power sleep state.

QEMU: Patched version of the current QEMU git master.

After making changes, re-runДЇrom under the kvm-kmod folder, and don't forget to copy and reload the kvm*.ko modules as shown above. Git clone git:///pub/scm/virt/kvm/kvm.gitДЄny hacking and modification of the KVM source will happen under the kvm repo.

KVM: Patched version of the current KVM git master:.

OK, here's what you'll need (or skip to the technical details instead): SomloДЇeedback to: somlo at cmu dot edu 0. Running Mac OS X as a QEMU/KVM Guest Gabriel L.