Vmware, Inc.

Leland Stanford Junior University

Scott W Devine

Lawrence S Rogel

Prashanth P Bungale

Edouard Bugnion

Mendel Rosenblum

Gerald A Fry

Beng-Hong Lim

Harvey Tuch

Pratap Subrahmanyam

Ole Agesen

Michael Nelson

Srinivas Krishnamurti

Julia B Austin

Edouard Bugnlon

S Rogel Lawrence

According to one aspect of the invention, a request to generate a state checkpoint of a computer is initiated within a user-level software entity, such as a virtual machine. Upon sensing the request, a checkpointing mechanism generates and stores at least one checkpoint, each checkpoint comprising a representation of the total state of the computer system. Upon sensing a state restoration request corresponding to one of the checkpoints, the checkpointing mechanism restores the checkpointed state in the computer, which can then resume operation from the restored total state. According to another aspect of the invention, a total checkpointed state is exported to another computer, where the state can be modified, for example, debugged, and then loaded into either the originally checkpointed computer (which, again, may be a virtual machine), or some other computer.

Mechanism for providing virtual machines for use by multiple users

A computing system includes a guest domain access control register (DACR), and guest first and second level page tables, the page tables containing domain identifiers used to obtain domain access information and access permission information, and the domain access information and the access permission information providing an effective guest access permission. The computing system provides a shadow page table, in which domain identifiers are used to identify domain access information in a processor DACR that are mapped from domain access information in the guest DACR, and in which access permissions are mapped from effective access permission information in the guest page tables and guest DACR. A memory management unit in the processor traverses the shadow page table, accesses the processor DACR, and combines the mapped domain access information in the processor with the mapped access permission in the shadow page table to reflect the guest intended effective access permissions.

Virtualizing processor memory protection with 'L1 iterate and L2 drop/repopulate'

One embodiment of the present invention is a method of migrating functionality to a target virtualized mobile device including virtualization software that supports one or more virtual machines, the method including: (a) embodying the functionality in a virtual machine; and (b) migrating the virtual machine to the target virtualized mobile device.

Migrating functionality in virtualized mobile devices

In a computing system having virtualization software including a guest operating system (OS), a method for executing guest OS instructions that includes: replacing each of one or more guest OS instructions with: (a) a translated instruction, which translated instruction is a one-to-one translation, or (b) a trap instruction.

Virtualization with in-place translation

A computing system includes virtualization software including a guest operating system (OS). A method maintains, by the virtualization software layer, a first shadow page table for use in a kernel mode and a second shadow page table for use in a user mode. The virtualization software switches between using the first shadow page table and the second shadow page table when the guest OS switches between operating in the kernel mode and the user mode.

Virtualization with multiple shadow page tables

In a computing system including a processor and virtualization software including a guest operating system (OS) that utilizes a guest domain access control register (DACR) containing domain access information and guest page tables including first level page tables (L1 page tables) and second level page tables (L2 page tables), which guest page tables contain: (a) domain identifiers used to obtain domain access information from the guest DACR and (b) access permission information, wherein the domain access information and the access permission information are combined to provide an effective guest access permission, in accordance with one embodiment, a method for providing shadow page tables and processor DACR settings that virtualize processor memory protection includes: the virtualization software providing a shadow page table wherein: (a) domain identifiers in the shadow page table are used to identify domain access information in the processor DACR that are mapped from the domain access information in the guest DACR; and (b) access permissions in the shadow page table that are mapped from the effective access permission information in the guest page tables and guest DACR; wherein a memory management unit (MMU) in the processor traverses the shadow page table, accesses the processor DACR, and combines the mapped domain access information in the processor with the mapped access permission in the shadow page table to reflect the guest intended effective access permissions while isolating the guest from the virtualization software.

Methods for providing shadow page tables that virtualize processor memory protection. In one embodiment, two shadow L2 page tables are maintained for each section, for example, each 1 MB section, of guest address space covered by a shadow L1 descriptor.

Virtualizing processor memory protection with 'L1 iterate and L2 swizzle'

Methods for providing shadow page tables that virtualize processor memory protection. In one embodiment, virtualization software maintains the following: (a) a mapping &#x3c6; from guest domain identifier to a set of shadow L2 page tables that back guest L1 sections marked with a domain identifier; and (b) with each such shadow L2 page table, a set &#x3c9; of back-pointers to 'potentially referencing' shadow L1 descriptors.

Virtualizing processor memory protection with 'domain track'

One or more embodiments provides a shadow page table used by a virtualization software wherein at least a portion of the shadow page table shares computer memory with a guest page table used by a guest operating system (OS) and wherein the virtualization software provides a mapping of guest OS physical pages to machine pages.

Virtualization with shadow page tables

One embodiment is a virtualized mobile device including virtualization software that supports one or more virtual machines and further includes: (a) device emulation software that communicates with device driver software in the one or more virtual machines; (b) device driver software that communicates with one or more physical devices of the mobile device; and (c) transformer stack software that interacts with the device emulation software and the device driver software.

Routing a physical device request using transformer stack to an equivalent physical device in a virtualized mobile device

In a computing system having virtualization software including a guest operating system (OS), a method for operating wherein virtualization software address space is distributed in guest OS address space that includes: granting the guest OS execute, but not read or write, access, to pages in the virtualization software address space.

Virtual machine execution using virtualization software with shadow page tables and address space interspersed among guest operating system address space

One embodiment is a method of controlling usage in a virtualized mobile device including virtualization software that supports one or more virtual machines, the method including: (a) receiving control information at the virtualized mobile device that includes one or more limits pertaining to one or more uses of the virtualized mobile device; (b) collecting usage information relating to the one or more uses; (c) determining whether usage information corresponding to one of the one or more uses exceeds a corresponding one of the one or more limits; and if so; (d) carrying out a predetermined action relating to the one of the one or more uses.

Controlling usage in mobile devices via a virtualization software layer

In a computing system having virtualization software including a guest operating system (OS), a method for providing page tables that includes: providing a guest page table used by the guest OS and a shadow page table and a shadow page directory used by the virtualization software wherein: at least a portion of the guest page table and the shadow page directory are the same; and the portions that are the same are shared in computer memory by the guest page table and the shadow page directory.

Growing community of inventors

Katonah, NY, United States of America

Scott W Devine