Exitless extended page table switching for nested hypervisors

A system comprising:

• one or more physical processors;
• a host hypervisor configured to execute on the one or more physical processors;
• and
• a guest configured to execute on one or more physical processors, the guest including a nested hypervisor, and a nested guest,
• wherein the nested hypervisor is configured to:
• write a plurality of pointer addresses to an extended page table list, wherein each of the plurality of pointer addresses is associated with one of a plurality of extended page tables;
• wherein the host hypervisor is configured to:
• verify that each of the plurality of pointer addresses corresponds to a guest physical address for one of the plurality of extended page tables;
• create a plurality of shadow extended page tables, each of which includes a shadow pointer address corresponding to a host physical address;
• write, in a local page table list, each shadow pointer address and an index of each of the plurality of shadow extended page tables;
• load the local page table list;
• and
• wherein the nested guest is configured to:
• request to switch between two of the plurality of extended page tables, from a first extended page table to a second extended page table;
• identify a matching entry for the second extended page table in the local page table list;
• and
• switch to the second extended page table without triggering a virtual machine exit.

A computer-readable non-transitory storage medium comprising executable instructions that, when executed, are configured to cause a host hypervisor, a nested hypervisor, and a nested guest to:

• write a plurality of pointer addresses to an extended page table list, wherein each of the plurality of pointer addresses is associated with one of a plurality of extended page tables;
• verify that each of the plurality of pointer addresses corresponds to a guest physical address for one of the plurality of extended page tables;
• create a plurality of shadow extended page tables, each of which includes a shadow pointer address corresponding to a host physical address;
• write, in a local page table list, each shadow pointer address and an index of each of the plurality of shadow extended page tables;
• load the local page table list,
• request to switch between two of the plurality of extended page tables, from a first extended page table to a second extended page table;
• identify a matching entry for the second extended page table in the local page table list;
• and
• switch to the second extended page table without triggering a virtual machine exit.