DPCs to the Rescue!

I finally fixed the CPU affinity issue, and have reason to believe I can now accurately initialize VMX on all active CPUs.

The trick was, instead of creating a thread for each CPU and trying to set the affinity, I can create a DPC object for each CPU. There's a nice little routine called KeSetTargetProcessorDpcEx which allows me to issue a DPC on a specific CPU. So, all I have to do is create a DPC for each CPU, target that CPU, and when the DPC runs, it just initializes VMX - no need to adjust the affinity mask. Perhaps one drawback is that, at least from my tests so far, they all run sequentially on the same thread; however, I don't think this'll be an issue because the initialization code is pretty fast and straightforward. Also, DPCs run at DISPATCH_LEVEL, meaning everything the DPC accesses (including the function itself!) must be non-paged.

Another difference is that I have to create a new DPC anytime I want to run code on a particular processor (in the future, this will include VM operations that are tied to a CPU, such as starting the VM), but again, this is no big deal, as DPCs are relatively straightforward.

I think I'm gonna call it quits for tonight - perhaps tomorrow, I can start working on actual VM creation.