alt Hacker NewsIt looks like the pass through part here was implemented using standard DriverKit interfaces, if I'm not mistaken. That is, the PCIe BAR can already be mapped from the user-space, without any extra modifications to macOS. It's just a matter of VMMs, such as QEMU, adopting this interface in addition to Linux VFIO and the like (unless you're talking about Virtualization.framework, which is kind of a VMM of its own).
What exactly do you feel macOS is missing?
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Isn't driverkit essentially a separate user space stack compared to regular code? I remember seeing the driverkit specific dyld caches in macos root partition images that included their own copies of everything down to libsystem. Getting driverkit code to run in the same process as normal user code seems like it'd be quite an uphill battle.
Presumably with the right entitlements you can just hit the same (presumably IOKit) syscalls that driverkit does. But that's an extra layer of reverse engineering, and you're not really using driverkit anymore.
>> This project requires a special entitlement from Apple. I’ve requested it, and heard they may be open to granting it, but I have not yet heard back, and I’m told that the wait time could be months.
> I have been bothering the VM team for years for VM GPU pass through.
Good luck. I'm sure they're keen on giving people access to this so that people can spend their money on NVIDIA GPUs instead of buying more expensive Macs. :)
Would of course be awesome, but I'd be very surprised if it happened.
I’m not very familiar with the specifics of pass through but IIUC only being able to map 1.5gb of active DMA buffers at a time is pretty limiting.