Abstract: Approaches for creating a template virtual machine. An in-memory state of a virtual machine and/or a set of applications executing within the virtual machine are adjusted and/or configured based on the intended use of the template virtual machine. Thereafter, the virtual machine is established as a template virtual machine. The template virtual machine may be used to create one or more virtual machines using a copy-on-write memory process.

Abstract: Managing the guest operating system's eviction of memory pages from a virtual machine. A guest operating system or a hypervisor may cause one or more memory pages within a guest physical frame to become unlikely or ineligible for selection as a candidate for eviction by the guest operating system. Each of the one or more memory pages may also reside, or be intended to reside, in the memory of one or more other virtual machines. In this way, memory pages that are shared across multiple virtual machines may become less likely to be evicted, thereby using memory more efficiently.

Abstract: Approaches for an operating system to ascertain whether files stored its file system have been deemed trustworthy. When an operating system receives a request to perform an operation involving a file that is stored within the file system maintained by the operating system, the operating system requests the file from a driver. In turn, the driver consults a set of trust data to identify whether the file has been previously deemed trustworthy. Upon the driver determining that the file has been deemed trustworthy, the driver provides the file to the operating system in a first format. On the other hand, upon the driver determining that the file has not been deemed trustworthy, the driver provides the file to the operating system in a second format that is different than the first format. Advantageously, the file is stored in a single format in the file system.

Abstract: Reducing an amount of memory used by a virtual machine. A system includes multiple virtual machines that share common pages of memory. The number of private pages associated with each virtual machine is minimized by ensuring that pages that a guest operating system regards as now free or zeroed are efficiently mapped by the hypervisor to a shared zero page. Upon a hypervisor determining that one or more guest physical frame numbers are assigned to free memory pages, the hypervisor updates mapping data to map the one or more guest physical frame numbers to a shared zero page within the machine frame.

Abstract: Mitigating eviction of the memory pages of virtualized machines. Upon detecting that a request to perform an I/O operation has been issued against a block stored a disk, a determination is made as to whether a pristine copy of the contents of the block is stored in memory. If a pristine copy of the contents of the block is stored in memory, then the request may be performed by updating mapping data that maps a page of memory to a location in memory at which the pristine copy is stored. In this way, the request is performed without performing the I/O operation against the block stored on disk. Various approaches for resharing memory, including memory of a template virtual machine, are discussed.

Abstract: A method of running an operating system comprises a two-step process. Firstly, in a set-up phase, there is carried out the loading of a driver when the operating system is booted, an operating system component transmitting a call to a kernel component for a function table, the driver intercepting the call from the operating system component to the kernel component, the driver replacing a specific callout in the function table with a replacement callout to the driver, the driver supplying the amended function table to the operating system component, the operating system component invoking the replacement callout to the driver, the driver invoking the original callout to the kernel component for a second function table, the driver replacing a specific function call in the second function table with a replacement function call to the driver, and the driver supplying the amended second function table to the operating system component.