viridian

关于viridian interface

At the moment we provide MSR access to APIC registers, and the hypercall

to yield the CPU when waiting for a spinlock.  We looked at a few others

(e.g. address-space-change hypercall) but found the benefits, if any,

were negligible.

The most important part of the interface is that we can use it to tell

Windows not to expect timer interrupt delivery to be as even across all

CPUs as it would be on bare metal.  This gets rid of annoying STOP 0x101

bluescreens in multi-vcpu Windows from Vista on.