QEMU can be installed from Homebrew: brew install qemu. SUSE: zypper install qemu. RHEL/CentOS: yum install qemu-kvm. Gentoo: emerge -ask app-emulation/qemu.
Qemu Emulator Cmu Mac OS X As ASomloAnswer (1 of 5): One solution that I didn’t directly see here, but as Micheal Lloyd hinted at, is using a webapp where the browser is the runtime environment. WindowsRunning Mac OS X as a QEMU/KVM Guest Gabriel L. QEMU requires Mac OS X 10.5 or later, but it is recommended to use Mac OS X 10.7 or later.![]() 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.2.2.2. Configure and build using something like:According 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. This may have a negative impact on e.g. 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.If we attempted to emulate MWAIT as (something similar to) HLT, while continuing to treat MONITOR as a NOP, we might be able to reduce host CPU utilization at the price of having the MWAIT-based idle thread be somewhat "sluggish" (waking up "late", on hardware interrupt, as opposed to "on time" when another VCPU writes to the monitored memory location). 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.Assuming 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. 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.As 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:Sudo rm /System/Library/Extensions/AppleIntelCPUPowerManagement.kextThis 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.Due 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. A plausible approach could work like this: not all VCPUs are guaranteed to receive hardware (e.g., timer) interrupts that would wake them from MWAITThese issues are currently under investigation, so please stay tuned.Although the spec strongly warns against assuming any connection between the size of the memory chunk being monitored and the size of a cache line, it is obvious that MONITOR and MWAIT are implemented on top of the processor's cache coherence protocol (e.g., MESI). However, when booting on an SMP guest, OS X crashes with an "HPET not found" panic, which could indicate any number of problems: The patch works well enough on a single-processor guest, reducing host CPU utilization during guest idle to about 15%. This experimental patch implements MWAIT as an always-interruptible (regardless of RFLAGS.IF) version of HLT. MWAIT acts as NOP if finds the monitor is "disarmed" otherwise, it enters a C-state and waits for a triggering write, or interrupt, etc.A relatively straightforward way to emulate MONITOR and MWAIT in KVM would be to utilize the virtual MMU module to write-protect MONITOR-ed memory areas, and handle the subsequent write faults (by emulating the actual guest write from within the host, and updating the state of the emulated monitoring hardware accordingly). When a monitored cache line is invalidated, the "armed" flag is also turned off (i.e., the monitoring hardware is "trigerred" or "disarmed"). a write to the monitored memory area from another CPU core will cause everyone else's (including the MONITOR-ing core's) corresponding cache line to be invalidated ( I state). write operations cause a fault and are handled (i.e., emulated) in host mode, but do not switch the page back to being writable instead, they set an "recently accessed" flag for the page. only the first MONITOR on a given page causes it to be write-protected. we assume a (very) limited number of MONITOR-ed memory locations is used by the guest (Mac OS X only utilizes one such location, which is shared by all instances of its idle thread). As an optimization step (to avoid a TLB shootdown each time the write-protection on a monitored page is switched on or off), the patch is implemented as folows: It is true that the exact extent of the monitored memory area is advertised via CPUID, but OS X is already known to have a poor track record of honoring CPUID.This new experimental patch implements MONITOR/MWAIT by emulating the monitoring hardware on top of the KVM MMU, as described above. Other times, as well as with any attempt at SMP higher than 2, we get the dreaded HPET panic. Some other times, the emulated disk controller (AHCI) hangs. The patch sometimes works with ' -smp 2,cores=2' (about 30% of the time) as shown in this screenshot. This step is not yet implemented in the current version of the patch.Similarly to the MWAIT as HLT method, this patch only works reliably on single-VCPU guests. The guest system's "physical" memory is allocated as part of the virtual address space of the QEMU process, and various handlers for the emulated virtual hardware of the guest systems are prepared. QEMU starts as a user-mode process, launching one thread for each VCPU that will be part of the guest VM. Here is roughly how QEMU and KVM work together to implement a guest VM: KVM, which allow it to run guests at near-native performance levels. For certain architectures (such as x86_64), QEMU is able to take advantage of hardware virtualization features offered through e.g. Mac intosh emulatorKVM handles the kernel-side of the ioctl() call made by each QEMU VCPU thread. Normally, when the userspace emulation is complete, the QEMU VCPU thread loops back to the spot where it calls into the kernel via the ioctl(). This typically involves a need for userspace emulation of specific guest hardware. This ioctl() call will only return to userspace if/when KVM encounters a VM exit it can't handle itself. Install a portable windows 7 for macMaster git repo: git://git.qemu.org/qemu.gitThere are four relevant topics regarding support for Mac OS X guests: QEMU's recent inclusion of support for the Q35/ICH9 based architecture emulation of Apple's System Management Controller (a.k.a. Otherwise, the VM exit reason is passed back to userspace by falling out of the ioctl() call, at which point QEMU must handle it as described above, before calling back into KVM again via the ioctl().A quick list of QEMU upstream resources might include: Whenever a VM exit (back to host mode) occurs, KVM attempts to handle the exit cause itself, and immediately re-enters VM guest mode if successful.
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