Abstract: In one embodiment, fault information relating to a fault associated with the operation of guest software is received. Further, a determination is made as to whether the fault information satisfies one or more fault filtering criteria. If the determination is positive, the guest software is permitted to disregard the fault.

Abstract: In one embodiment, the present invention includes a method of transitioning control to guest software in a virtual machine from a virtual machine monitor, receiving control following a transition from the virtual machine to the virtual machine monitor upon an event, and determining whether to modify a state of the guest code, a state of the virtual machine monitor or a state of controls. If such a determination is made, the state may be modified and control is transitioned back to the guest software.

Abstract: In one embodiment, information pertaining to a first fault occurring during operation of a virtual machine (VM) is stored in a first field. A second fault is detected while delivering the first fault to the VM, and a determination is made as to whether the second fault is associated with a transition of control to a virtual machine monitor (VMM). If this determination is positive, information pertaining to the second fault is stored in a second field, and control is transitioned to the VMM.

Abstract: A system and method for allowing a virtual machine monitor to assume control of a system when the current privilege level of guest software meets a privilege level exiting criteria. The processor detects that the current privilege level meets the criteria and then transfers control from the guest software to the virtual machine monitor. The virtual machine monitor may decline to assume control for certain privilege level changes or values.

Abstract: In one embodiment, a method for supporting address translation in a virtual-machine environment includes creating a guest translation data structure to be used by a guest operating system for address translation operations, creating an active translation data structure based on the guest translation data structure, and periodically modifying the content of the active translation data structure to conform to the content of the guest translations data structure. The content of the active translation data structure is used by a processor to cache address translations in a translation-lookaside buffer (TLB).

Abstract: In one embodiment, a method includes receiving a request to transition control to a virtual machine (VM) from a virtual machine monitor (VMM), determining that a single-stepping indicator is set to a single stepping value, and transitioning control to the VM. Further, if an execution of a first instruction in the VM completes successfully, control is transitioned to the VMM following the successful completion of the execution of the first instruction.

Abstract: In one embodiment, a method includes transitioning control to a virtual machine (VM) upon receiving a request from a virtual machine monitor (VMM), determining that the request to transition control is associated with a request to be informed of an open event window, performing an event window check to determine whether an even window of the VM is open, and transitioning control to the VMM if the event window check indicates that the event window of the VM is open.

Abstract: In one embodiment, a method for supporting address translation in a virtual-machine environment includes creating a guest translation data structure to be used by a guest operating system for address translation operations, creating an active translation data structure based on the guest translation data structure, and periodically modifying the content of the active translation data structure to conform to the content of the guest translations data structure. The content of the active translation data structure is used by a processor to cache address translations in a translation-lookaside buffer (TLB).

Abstract: In one embodiment, an apparatus includes a set of multiplex blocks coupled with an interrupt controller and multiple interrupt request lines, and a virtual machine monitor block (VMM) coupled to the set of multiplex blocks. Each multiplex block corresponds to a distinct interrupt request line. Each multiplex block is to route the interrupt request signal received via the corresponding interrupt request line either to the interrupt controller or the VMM block depending on a current configuration value of this multiplex block.

Abstract: One embodiment of the present invention is a technique to invalidate entries in a translation lookaside buffer (TLB). A TLB in a processor has a plurality of TLB entries. Each TLB entry is associated with a virtual machine extension (VMX) tag word indicating if the associated TLB entry is invalidated according to a processor mode when an invalidation operation is performed. The processor mode is one of execution in a virtual machine (VM) and execution not in a virtual machine.

Abstract: One embodiment of the present invention is a technique to invalidate entries in a translation lookaside buffer (TLB). A TLB in a processor has a plurality of TLB entries. Each TLB entry is associated with a virtual machine extension (VMX) tag word indicating if the associated TLB entry is invalidated according to a processor mode when an invalidation operation is performed. The processor mode is one of execution in a virtual machine (VM) and execution not in a virtual machine.

Abstract: In one embodiment, a method includes recognizing an interrupt pending during an operation of guest software, determining that the interrupt is to cause a transition of control to a virtual machine monitor (VMM), determining whether the interrupt is to be acknowledged prior to the transition of control to the VMM, and if the interrupt is to be acknowledged, acknowledging the interrupt and transitioning control to the VMM.

Abstract: In one embodiment, a method for handling privileged events in a virtual machine environment includes detecting an occurrence of a privileged event, determining which one of multiple virtual machine monitors (VMMs) is to handle the privileged event, and transitioning control to this VMM.

Abstract: In one embodiment, when it is determined that a modification of content of an active address translation data structure is required, an entry in the active address translation data structure is modified to conform to a corresponding entry in a guest address translation data structure. During the modification, a bit field including one or more access control indicators in the entry of the active address translation data structure is not overwritten with corresponding data from the guest address translation data structure.

Abstract: In one embodiment, an occurrence of an interrupt is identified during the operation of guest software. Further, a determination is made as to whether the interrupt is managed by guest software. The determination depends on the current value of an interrupt control indicator. If the interrupt is not managed by guest software, control is transitioned to a virtual machine monitor (VMM) if the VMM is ready to receive control.

Abstract: In one embodiment, a method for resolving address space conflicts includes detecting that a guest operating system attempts to access a region occupied by a first portion of a virtual machine monitor and relocating the first portion of the virtual machine monitor within the first address space to allow the guest operating system to access the region previously occupied by the first portion of the virtual machine monitor.

Abstract: In one embodiment, fault information relating to a fault associated with the operation of guest software is received. Further, a determination is made as to whether the fault information satisfies one or more fault filtering criteria. If the determination is positive, the guest software is permitted to disregard the fault.

Abstract: A simultaneous multi-threaded architecture combines OS priority information with thread execution heuristics to provide dynamic priorities for selecting thread instructions for processing. The dynamic priority of a thread is determined by adjusting a heuristic measure of the thread's execution dynamics with a priority-dependent scaling function determined from the OS priority of the thread. An SMT processor includes logic for calculating a scaling function for each thread scheduled on the processor, tracking the threads' heuristics, and combing the scaling function and heuristic information into a dynamic priority for each thread. Instructions are selected for execution from among the scheduled threads according to the threads' dynamic priorities.

Abstract: In one embodiment, a command pertaining to one or more portions of a register is received from guest software. Further, a determination is made as to whether the guest software has access to all of the requested portions of the register based on indicators within a mask field that correspond to the requested portions of the register. If the guest software has access to all of the requested portions of the register, the command received from the guest software is executed on the requested portions of the register.

Abstract: In one embodiment, a method for resolving address space conflicts includes detecting that a guest operating system attempts to access a region occupied by a first portion of a virtual machine monitor and relocating the first portion of the virtual machine monitor within the first address space to allow the guest operating system to access the region previously occupied by the first portion of the virtual machine monitor.