Network interface card device pass-through with multiple nested hypervisors

A method comprising:

• in a data center, running multiple nested hypervisors including an outer hypervisor and at least one inner hypervisor running as a virtual machine on top of the outer hypervisor;
• running a guest operating system as a virtual machine in the inner hypervisor;
• communicating external to the data center by a network interface card device in communication with the outer hypervisor via a network interface card device driver;
• executing an emulated network interface card device in the inner hypervisor and an emulated network interface card device in the outer hypervisor;
• executing an extender component in the outer hypervisor and an extender component in the inner hypervisor such that the extender components in the outer hypervisor and the inner hypervisor are architecturally cascaded;
• and
• using the extender components in the outer hypervisor and in the inner hypervisor, assigning an interface for the guest operating system to the emulated network interface card device in all nested hypervisors to enable network communications between the guest operating system and the network interface card device to bypass the outer hypervisor and the inner hypervisor, wherein the assigning includes:
• executing in the inner hypervisor an emulated network interface card device driver that provides just pass-through related control operations from the outer hypervisor emulated network interface card device to the inner hypervisor, the pass-through related control operations including discovering hardware capabilities of a device virtual function and one or more of allocating, configuring and freeing the device virtual function;
• and
• accessing the pass-through related control operations using the emulated network interface card device driver.

One or more non-transitory computer readable storage media encoded with software comprising computer executable instructions and when the software is executed operable to:

• in a data center computing system, run multiple nested hypervisors including an outer hypervisor and at least one inner hypervisor running as a virtual machine on top of the outer hypervisor;
• run a guest operating system as a virtual machine in the inner hypervisor;
• execute an emulated network interface card device in the inner hypervisor and an emulated network interface card device in the outer hypervisor;
• execute an extender component in the outer hypervisor and an extender component in the inner hypervisor such that the extender components in the outer hypervisor and the inner hypervisor are architecturally cascaded;
• using the extender components in the outer hypervisor and in the inner hypervisor, assign an interface for the guest operating system to the emulated network interface card device in all nested hypervisors to enable network communications between the guest operating system and a network interface card device to bypass the outer hypervisor and the inner hypervisor, wherein the instructions operable to assign include instructions operable to:
• execute in the inner hypervisor an emulated network interface card device driver that provides just pass-through related control operations from the outer hypervisor emulated network interface card device to the inner hypervisor, the pass-through related control operations including discovering hardware capabilities of a device virtual function and one or more of allocating, configuring and freeing the device virtual function;
• and
• access the pass-through related control operations using the emulated network interface card device driver.