Abstract: A system and method for withdrawing virtual processors from virtual machines (VMs) are disclosed. In accordance with one embodiment, a hypervisor executed by a computer system detects when a measure of system load for a virtual machine falls below a threshold. In response, the hypervisor withdraws a virtual processor from the virtual machine.

Abstract: A system and method for hibernating virtual machines (VMs) are disclosed. In accordance with one embodiment, a computer system that executes a hypervisor and a virtual machine (VM) receives a request from a first virtual processor of the VM to put the VM to sleep. In response, the hypervisor stops a second virtual processor of the VM.

Abstract: A system and method for waking hibernating virtual machines (VMs) are disclosed. In particular, a host operating system (OS) may decide to wake a hibernating VM in response to a message received by the host, such as an incoming networking packet, a message generated by an external event (e.g., a hardware device fault, an interrupt, etc.), etc. In accordance with one embodiment, the decision whether to wake a hibernating VM may be based on a sender of the message.

Abstract: A method and system for managing a virtual computing system including a virtual machine (VM) configured to send an event to a host CPU executing a memory monitoring instruction. The virtual machine is configured to receive from a hypervisor a notification identifying an address range writeable by a virtual central processing unit (VCPU) associated with the virtual machine to send an event to a host central processing unit (CPU). The virtual machine is further configured to receive an instruction to write to the identified address range for sending an event to the host CPU. The VCPU of the virtual machine may then write data identifying an event for execution by the host CPU to the identified address range, without causing an exit to the hypervisor.

Abstract: A system and method for display power management in a virtualized environment are disclosed. In accordance with one embodiment, a hypervisor that is executed by a first computer system receives a notification that a host operating system of a second computer system has received a command to dim a video display of the second computer system, and forwards the notification to a guest operating system of a virtual machine hosted by the first computer system. The hypervisor receives from the guest operating system a first signal that indicates that the hypervisor is to notify the host operating system to refrain from executing the command. The hypervisor then transmits a second signal that notifies the host operating system to refrain from executing the command.

Abstract: A system and method for allocating additional virtual processors to virtual machines (referred to as “automatic processor hotplug”) are disclosed. In accordance with one embodiment, a guest operating system of a virtual machine detects when a measure of system load exceeds a threshold. In response, the guest operating system transmits a request to a hypervisor for an additional virtual processor for the virtual machine.

Abstract: A system and method are disclosed for creating a virtual machine template from a live virtual machine. In accordance with one embodiment, a computer system creates a live snapshot of a virtual machine, and creates a clone of the virtual machine based on the live snapshot. The computer system then initiates execution of the clone, shuts down the clone, and creates a virtual machine template based on the clone, where the virtual machine template enables the creation of another virtual machine that corresponds to the live snapshot of the original virtual machine.

Abstract: A system and method are disclosed for preventing concurrent access by a virtual machine and a clone of the virtual machine to a resource in a non-shareable state. In accordance with one embodiment, a hypervisor receives a command to clone a virtual machine, and determines whether any resource used by the virtual machine is in a non-shareable state (e.g., the virtual machine holds a lock on a resource, a resource comprises memory that stores secure data, etc.). When any resource used by the virtual machine is in a non-shareable state, the hypervisor delays cloning of the virtual machine until all resources used by the virtual machine are in a shareable state.

Abstract: A mechanism for memory change tracking during migration of a virtual machine (VM) with VM-controlled assigned peripherals is disclosed. A method of the invention includes informing a write tracking module of an interest by a hypervisor of a host machine in a specific memory location associated with a peripheral device that is controlled by a VM managed by the hypervisor, receiving notification from the write tracking module that the identified specific memory location has been modified by the peripheral device, and marking a memory page of the specific identified memory location as dirty in order for the migration of the memory page to be repeated as part of a migration process of the VM to a destination host machine.

Abstract: A method and system for providing guest software updates to a host computer system. The hypervisor in the host computer system downloads an update to guest software that runs on a virtual machine associated with the hypervisor. The hypervisor determines the content of the update to be sent to the virtual machine. The hypervisor then sends the content of the update to the virtual machine via a dedicated channel between the hypervisor and the virtual machine. Thus, a guest without external networking or even no network stack can be updated.

Abstract: A system and method for display power management in a virtualized environment are disclosed. In accordance with one embodiment, a hypervisor receives a notification that a host operating system has received a command to dim a display, and forwards the notification to a guest operating system hosted by a virtual machine. The hypervisor receives from the guest operating system a first signal that indicates that the hypervisor is to notify the host operating system to refrain from executing the command. The hypervisor then transmits a second signal that notifies the host operating system to refrain from executing the command.

Abstract: A system and method are disclosed for managing a plurality of virtual machines (VMs) in a fault-tolerant and low-latency manner. In accordance with one example, a computer system executes a first VM and a second VM, and creates a first live snapshot of the first VM and a second live snapshot of the second VM. The computer system detects, after the creating of the first live snapshot and the second live snapshot, a failure that affects the executing of the first VM, and in response destroys the first VM and the second VM, creates a third VM from the first live snapshot and a fourth VM from the second live snapshot, and initiates execution of the third VM and the fourth VM. An output transmitted by the first VM to the second VM during the creating of the first live snapshot and the second live snapshot is not blocked.

Abstract: A mechanism for memory change tracking during migration of a virtual machine (VM) with VM-controlled assigned peripherals is disclosed. A method of the invention includes interacting with a VM executed by a hypervisor of a origin host machine in order to cause the VM to prevent a state of a peripheral device controlled by the VM from changing, receiving the state of the peripheral device from at least one of the VM, a memory of the VM, or the peripheral device, and transferring the obtained state of the peripheral device to a destination host machine as part of a migration process of the VM.

Abstract: A system and method for protecting secure data from virtual machine clones are disclosed. In accordance with one embodiment, a hypervisor transmits a message to a guest operating system hosted by a first virtual machine, where the message identifies a memory location for a secure datum. After the transmission of the message, when the hypervisor receives a direct-copy command to clone the first virtual machine, the hypervisor creates a second virtual machine via direct copy, where the second virtual machine is not provided access to the secure memory location during its creation.

Abstract: A method and system for permitting a guest to program a message-signaled interrupt-based device is disclosed. A hypervisor of a host detects a request by a guest to map an address range of memory of the guest to a message signaled-interrupt capability table associated with a device. The hypervisor maps the message signaled-interrupt capability table from a message signaled-interrupt capability register of a programmable interrupt controller associated with the host to the address range of memory of the guest. The hypervisor detects an attempt by the guest to program the device with the message-signaled interrupt configuration located in the address range of memory of the guest. The hypervisor programs the device with the message-signaled interrupt configuration specified by the guest in the address range of memory of the guest.

Abstract: A system and method are disclosed for managing a plurality of virtual machines (VMs) in a fault-tolerant and low-latency manner. In accordance with one example, a computer system executes a first VM and a second VM, and creates a first live snapshot of the first VM and a second live snapshot of the second VM. The computer system detects, after the creating of the first live snapshot and the second live snapshot, a failure that affects the executing of the first VM, and in response destroys the first VM and the second VM, creates a third VM from the first live snapshot and a fourth VM from the second live snapshot, and initiates execution of the third VM and the fourth VM. An output transmitted by the first VM to the second VM during the creating of the first live snapshot and the second live snapshot is not blocked.

Abstract: A system and method for protecting secure data from virtual machine clones are disclosed. In accordance with one embodiment, a hypervisor receives a message from a guest operating system hosted by a first virtual machine, where the message identifies a memory location (e.g., of main memory, of a storage device, etc.) for a secure datum. After the hypervisor receives a direct-copy command to clone the first virtual machine, the hypervisor creates a second virtual machine via direct copy, where the second virtual machine is not provided access to the secure memory location during its creation.

Abstract: A method and system for managing message-signaled interrupt-based events sent from an event source to a host or a guest is disclosed. A central processing unit instructs an event source to write a message-signaled interrupt to a designated address of a random access memory of the host. The host or a guest of the central processing unit executes a memory monitoring instruction to the designated address. The host or the guest enters a wait state. The host or the guest detects a write of the message-signaled interrupt by the event source to the designated address, the message-signaled interrupt comprising data items pertaining to an event to be performed. The host or the guest exits from the wait state. The host or the guest performs an atomic operation with respect to the event based on the data items in the message-signaled interrupt.

Abstract: A method and system for managing multiple queues of a networking device associated with a host machine in a virtual machine system. The networking device includes multiple dedicated queues and shared queues that are used by multiple guests of the virtual machine system for the transmission and/or receipt of packets in a data communication. A hypervisor of the virtual machine system manages the assignment of the multiple queues to the multiple guests by dynamically mapping addresses of the virtual machines based on determination of a load placed on the queues.

Abstract: A method and system for managing a virtual computing system including a hypervisor managing a virtual machine (VM) configured to communicate with a thread executable by multiple host central processing units (CPUs), using memory monitoring instructions. The hypervisor provides the virtual machine with a first notification identifying a first designated memory range writeable by a virtual central processing unit (VCPU) associated with the virtual machine and a first instruction to write to the first designated memory range to communicate with the thread running on a first host CPU. The hypervisor further identifies movement of the thread from the first host CPU to a second host CPU and provides to the virtual machine a second notification identifying a second designated memory range and a second instruction to write to the second designated memory range to communicate with the thread running on the second host CPU.