Hypervisor context switching using a redirection exception vector in processors having more than two hierarchical privilege levels

A non-transitory computer-readable storage medium comprising instructions, which when executed in a computer system operable in more than two hierarchical privilege levels, causes the computer system to carry out the steps of:

• assigning a first component and a second component to a first privilege level;
• setting one or more entries in an exception vector table to install a redirection exception vector at a second privilege level that is less privileged than the first privilege level, the redirection exception vector configured to respond to an exit from a third privilege level, which is less privileged than the second privilege level, with a bounce to the first privilege level;
• causing the first component to run one or more commands at the third privilege level that is less privileged than the second privilege level;
• while the first component is running one or more commands at the third privilege level, determining that a first context switch from the one or more commands running at the third privilege level to the first privilege level is to be performed and in response thereto, exiting the third privilege level and entering the second privilege level in response to exiting the third privilege level, bouncing from the second privilege level to the first privilege level based on the redirection exception vector;
• configuring a state associated with the first privilege level;
• and executing the second component at the first privilege level.

A system of executing a context switch between hypervisor components in a computer system operable in more than two hierarchical privilege levels, comprising:

• A memory and a processor configured to:
• assign a first component and a second component of a hypervisor to a first privilege level;
• set one or more entries in an exception vector table to install a redirection exception vector at a second privilege level that is less privileged than the first privilege level, the redirection exception vector configured to respond to an exit from a third privilege level, which is less privileged than the second privilege level, with a bounce to the first privilege level;
• cause the first component to run one or more commands at the third privilege level that is less privileged than the second privilege level;
• while the first component is running the one or more commands at the third privilege level, determine that a first context switch from the one or more commands running at the third privilege level to the first privilege level is to be performed and in response thereto, exiting the third privilege level and entering the second privilege level;
• in response to exiting the third privilege level, bounce from the second privilege level to the first privilege level based on the redirection exception vector;
• configure a state associated with the first privilege level;
• and
• execute the second component at the first privilege level.