Microsoft Technology Licensing, LLC

Workman Nydegger

Microsoft Cororation

Andrew Ernest Nicholas

Rene Antonio Vega

Jacob Kappeler Oshins

Eric P Traut

Shuvabrata Ganguly

Idan Avraham

Ellsworth Davis Walker

Xiongjian Fu

Aaron Sebastian Giles

Manish Chablani

Osama M Salem

John Andrew Starks

Omar H Shahine

Linden B Siahaan

Lawrence Ralph Cleeton

Douglas A Watkins

Andrei Warkentin

David Ari Litwin

Michael P Foley

Rich Yampell

One or more virtual processors can be added or removed from a virtual machine based on CPU pressure measured within the virtual machine. In addition to the foregoing, CPU pressure can also be used to determine whether to remove a virtual processor from a virtual machine, which may cause the computer system to consume less power. In the alternative, virtual processors can be parked and/or unparked in order to reduce the amount of power consumed by the virtual machine. In addition, virtual processors can be forcibly parked during a migration operation.

Virtual processor allocation techniques

A catch-up mode that runs a virtual programmable interrupt timer faster than a nominal rate to prevent time loss in a virtual machine can be implemented. If time loss is determined, a catch-up mode can be initiated to cause increased firings, beyond a nominal rate, of the programmable interrupt timer to adjust the clock of the virtual machine to the clock of the host system. The virtual programmable interrupt timer can also be readjusted to a predetermined nominal rate when the time loss in the guest operating system is determined approximately within a predetermined tolerance range. The catch-up mode can be monitored to avoid 'interrupt storms' on the virtual machine. The virtual programmable interrupt timer can be altered by the guest operating system to accommodate different operating systems.

Changing frequency of a virtual programmable interrupt timer in virtual machines to control virtual time

Various mechanisms are disclosed herein for the saving and restoring of virtual machine environment state. For example, virtual machine state can be either be saved or (multiple) snapshots can be taken of the virtual machine state. In the latter case, virtual processors can be allowed to run while the memory of the virtual machine state is being saved. In either case, virtual devices associated with the virtual machine environment can be quiesced such that these devices can prepare themselves to be saved. Once such virtual devices and memory are saved, they can also be restored. For example, restoration of memory can occur while virtual processors are running at the same time. And, moreover, restoration can occur in batches of pages, thus optimizing the response time for restoring saved data.

Concurrent virtual machine snapshots and restore

Techniques for creating crash data in a virtualized environment are disclosed. In an embodiment of the present disclosure the techniques can be used when a guest operating system within a virtual machine may not have a sufficient mechanism for generating crash data.

Virtual machine crash file generation techniques

Techniques for reducing virtual machine input/output emulation overhead and decreasing the attack surface of a virtual machine architecture are disclosed.

Virtual machine fast emulation assist

A host operating system can take ownership of a device. The host can project the presence of a device proxy (VDP) into a guest operating system. The VDP provides a set of device functions corresponding to the particular device class. Interactions with the VDP in the guest are forwarded to a Virtual Service Provider (VSP) in the host. The VSP maps a set of device class functions onto physical devices through a hardware abstraction and emulation layer. Functions supported directly by a physical device can be delivered to the device by the hardware abstraction layer (HAL). Functions not directly supported can be implemented through the hardware emulation layer (HEL). A uniform and robust set of functions may be made available in the guest regardless of hardware changes in the host, migration to a new host, or use of the device by other competing operating systems.

Systems and methods for supporting device access from multiple operating systems

A method and system for printing from a guest operating system that executes in a virtual PC. In the guest operating system, a special printer driver (or extension to an existing printer driver) is installed. The printer driver receives print data from the guest operating system and applications that execute therein. The printer driver or an extension thereof forwards the print data or data derived therefrom to a host component that executes in a host operating system. The host component forwards the print data or data derived therefrom to the normal print mechanisms within the host operating system.

Virtual PC printer driver

Growing community of inventors

Sunnyvale, CA, United States of America

Andrew Ernest Nicholas