Enlightenment for low overhead hardware access

A method of operating an operating system in a guest partition, the method comprising:

• operating at least one physical processor to:
• implement a first emulated processor having a first time stamp counter;
• implement a second emulated processor having a second time stamp counter;
• execute computer-executable instructions implementing the operating system within the guest partition executing on the first emulated processor during a first period of time, the implementing comprising performing a timer operation based on a timer value obtained from the first time stamp counter;
• execute computer-executable instructions implementing the operating system within the guest partition executing on the second emulated processor during a second period of time, the implementing comprising performing a timer operation based on a timer value obtained by computing a normalized reference time from a value obtained from the second time stamp counter, the computing the normalized reference time comprising:
• obtaining a scale factor and an offset;
• and
• calculating the normalized reference time by applying the offset and the scale factor to the value obtained from the second time stamp counter.

A method of supporting a normalized reference time in a guest partition executing on a hypervisor, the hypervisor executing on a computer, the method performed by the hypervisor when a guest partition is restored, the method comprising:

• operating at least one physical processor on the computer to:
• updating a maximum time stamp counter value;
• store a value of a scale factor for the computer in a shared page, the shared page being shared between the hypervisor and the guest partition;
• compute an offset based on the scale factor and the maximum time stamp counter value;
• and
• store the offset in the shared page.