Method and system for a second level address translation in a virtual machine environment

A system to determine a host physical address from a guest virtual address in a virtual machine environment, the system comprising:

• a host memory;
• first level address translation hardware performing an address translation from a guest virtual address to a guest physical address;
• second level address translation hardware performing an address translation from a guest physical address to a host physical address;
• a translation look-aside buffer having translations between guest virtual addresses and corresponding host physical addresses;
• host software functionality forming a virtual machine monitor (VMM), the VMM accommodating multiple virtual machine programs along with a host operating system;
• a host processor, executing instructions and performing steps comprising:
• receiving a guest virtual address;
• checking the translation look-aside buffer (TLB) to determine if there is a pre-existing mapping between the guest virtual address and a corresponding host physical address, wherein if the pre-existing mapping exists, using the pre-existing mapping to access the host physical address, and wherein if the pre-existing mapping does not exist, then performing the translation as follows:
• inputting the guest virtual address into the first level translation hardware;
• determining at least one of intermediate and final guest physical addresses using the first level address translation hardware;
• inputting the at least one of the intermediate and final guest physical addresses into the second level address translation hardware;
• determining a host physical address and access override information using the second level address translation hardware, wherein the second level address translation hardware uses the guest physical address as an index, and wherein the use of the guest physical address as an index comprises performing a hash with the guest physical address, the hash determining an index for a table containing the host physical address and the access override information;
• and
• providing the host physical address and access override information to the host processor;
• wherein, the access override information performs access control over the host physical address, the access control overriding a guest-defined access protection on the at least one of intermediate and final guest physical address, and wherein the translation from the guest virtual address to the host physical address is performed without intervention by the VMM.

A computer-readable storage medium having computer-executable instructions for performing a method of performing a translation from a guest virtual address to a host physical address in a virtual machine environment having a virtual machine monitor (VMM), the method comprising:

• receiving a guest virtual address;
• checking a translation look-aside buffer (TLB) to determine if there is a pre-existing mapping between a guest virtual address and a corresponding host physical address, wherein if the pre-existing mapping exists, using the pre-existing mapping to access the host physical address, and wherein if the pre-existing mapping does not exist, then performing the translation as follows:
• inputting the guest virtual address into first level translation hardware;
• translating the guest virtual address into a guest physical address using the first level address translation hardware;
• inputting the guest physical address into second level address translation hardware;
• translating the guest physical address into a host physical address and an access override information using the second level address translation hardware using at least one table and the guest physical address as an index, and performing a hash with the guest physical address, the hash determining an index for a table containing the host physical address and the access override information;
• and
• providing the host physical address and access override information to a host processor in the virtual machine environment;
• wherein, the access override information performs access control over the host physical address, the access control overriding a guest-defined access protection on the guest physical address, and wherein the translation from the guest virtual address to the host physical address is performed without intervention by the VMM.