Abstract: A fault-tolerant virtualized computer system comprises a primary host executing a primary virtual machine (VM) and a backup host executing a backup VM. In one embodiment, each VM includes a virtual disk mapped to a shared disk image on physical disk accessible to both hosts. A virtual disk IO request is received by virtualization software executing on the backup host from a backup VM. When the virtual disk IO request is a read request, the virtual disk IO request is mapped to a physical read IO request of a virtual disk image stored on a physical disk, the physical read IO request is issued to the physical disk. However, when the virtual disk IO request is a write request, it is assumed to be completed without mapping the virtual disk IO request or issuing a mapped physical IO request to the physical disk.

Abstract: A method for sharing a network connection between a host system and a virtual machine is disclosed. The method includes sending an outgoing data frame from the virtual machine to a computer network. The host system is enabled to use the network connection using a first layer 2 address and a first layer 3 address. The first layer 2 and the first layer 3 addresses are associated with the network connection. The virtual machine is enabled to attempt to use the network connection using a second layer 2 address and a second layer 3 address. The first layer 3 and the second layer 3 addresses are compliant with IPv6. An occurrence of the second layer 2 address is replaced within the outgoing data frame with the first layer 2 address. If the outgoing data frame includes a network discover protocol (NDP) message of a selected type, the second layer 2 address in the NDP message is replaced by the first layer 2 address.

Abstract: Methods, systems and computer programs for migrating a virtual machine (VM) executing on a first host to a second host are presented, where the first host and the second are on different networks. One embodiment of a method includes assigning to the VM a VM address (VMA) belonging to a VM network and publishing a first route to an associated network (AN) via a first virtual router executing on the first host. The method further includes migrating the VM from the first host to the second host, the VM maintaining the assigned VMA after migrating, and publishing a second route to the AN via a second virtual router executing on the second host. The first and second virtual routers have addresses belonging to the VM network, and network packets to and from the VM flow through the virtual router where the VM is executing. A temporary tunnel between the virtual routers allows traffic to flow to the VM while the new route to AN is propagated throughout the network.

Abstract: A method and system of managing data access in a shared memory cache of a processor are disclosed. The method includes probing one or more memory addresses that map to a subset of the shared memory cache and sensing a plurality of events in the one or more memory addresses. Cache utilization information is then obtained by reading a hardware performance counter of the processor. The hardware performance counter is incremented based on the occurrence of the plurality of events. Based upon the cache utilization information, an occurrence of one of the plurality of events is reduced.

Abstract: In a virtualized computer system, a network frame is transmitted from a virtual machine using a network interface device, possibly through a virtual switch, by copying only a part of the network frame to the transmit buffers that have pre-translated mappings from guest physical addresses to hypervisor virtual addresses and to machine addresses. The length of the part of the network frame that is copied to the transmit buffers may be variable.

Abstract: Methods, systems, and computer programs for measuring performance of virtual desktop services offered by a server computer are presented. The method includes receiving from a client computer an action request to be executed at the server computer, where the server computer is configured to generate display views for the requesting client. The method further embeds, at the server computer, a first encoded pixel into a first image frame that is communicated to the client computer when acknowledging receipt of the action request. Further, the method embeds a second encoded pixel into a second image frame that is communicated to the client computer after completion of the action associated with the action request. Action performance time is stored in memory, where the action performance time is the time between arrivals of the first and second image frames at the client computer. The stored timing information is used to generate statistical performance data.

Abstract: One embodiment of the present invention is a method for enabling a computer system to run multiple multipathing software modules which includes: (a) scanning for physical devices; (b) scanning for paths to each of the physical devices; (c) presenting the paths to one or more multipathing software modules of a plurality of multipathing software modules operating within the computer system; (d) the multipathing software modules claiming or rejecting one or more of the one or more paths; and (e) creating and exposing one or more logical devices, wherein each logical device is associated with a multipathing software module.

Abstract: In a computer system, a method of controlling coalescence of interrupts includes dynamically basing a current level of interrupt coalescing upon a determination of outstanding input/output (I/O) commands for which corresponding I/O completions have not been received. Deliveries of interrupts are executed on the basis of the current level and in an absence of enabling timing-triggered delivery of an interrupt.

Abstract: A method is provided for creating and maintaining the validity of a cache group including one or more cache elements. Each of the cache elements corresponds to a different address space in a virtual memory of a computer system. Each of the cache elements include one or more caches that store mappings from virtual addresses to data or values that are functions of or dependent upon physical addresses that correspond to the virtual addresses. When there is an address space switch from a first address space to a second address space, the cache group is searched to find the cache element corresponding to the second address space, and that found cache element is made the current cache element for virtual memory access through the cache element. Changes in the page tables are also detected and reflected in the caches of the cache group to maintain the caches up-to-date.

Abstract: An apparatus for automatically generating source code files in a file storage unit is disclosed. The apparatus includes a file storage unit that stores the source code files, a code generator unit that generates at least some of the source code files, wherein the code generator unit comprises, and a file unit that monitors the file storage unit to detect changes in the file storage unit and in response send file event notifications. A metadata unit that builds a metadata model relating to the source code files in the file storage unit is also provided. The metadata model comprises a plurality of metadata items, each metadata item comprises a metadata section containing metadata, a key that identifies the metadata item, and one or more dependencies of the metadata items in relation to other of the metadata items. The metadata unit sends metadata notifications according to changes to the dependencies of the metadata items.

Abstract: Remote desktop servers include a display encoder that maintains a secondary framebuffer that contains display data to be encoded and transmitted to a remote client display. The display encoder submits requests to update the display data in the secondary framebuffer to a video adapter driver that has access to a primary framebuffer whose display data is updated according to drawing commands received from applications running on the remote desktop servers. The video adapter driver utilizes a spatial data structure to track changes made to the display data located in regions of the primary framebuffer and copies the display data in those regions of the primary framebuffer to corresponding regions in the secondary framebuffer.

Abstract: Remote desktop servers include a display encoder that maintains a secondary framebuffer that contains display data to be encoded and transmitted to a remote client display and a list of display primitives effectuating updated display data in the secondary framebuffer. The display encoder submits requests to receive the list of drawing primitives to a video adapter driver that receives and tracks drawing primitives that, when executed, update a primary framebuffer.

Abstract: In a method of updating software on a dormant disk, exposed files are accessed. The exposed files are exposed by mounting the dormant disk. The exposed files are scanned to determine the status of software residing on the dormant disk. The scanning is achieved without requiring booting of the dormant disk. It is determined whether an update is available for the software residing on the dormant disk.

Abstract: A method and system of disablement of an exception generating operation of a client system are disclosed. In an embodiment, a method is disclosed in which a snapshot of a client system is acquired. An execution of the client system is recorded, and a system wide exception is intercepted before it causes a client system crash. The execution of the client system is replayed from the snapshot of the client system, and an operation that generates the system wide exception is disabled.

Abstract: One or more processes are offloaded from one virtual machine running on one host computer to another virtual machine running on another host computer so that load balancing can be performed on a per process level and physical servers supporting the virtual machines can be more optimally utilized. Migrating one or more processes from a virtual machine running on a first host computer to a second host computer includes replicating the virtual machine on the second host computer, terminating the migrated processes from the virtual machine running on the first host computer, and terminating all user-level processes running on the replicated virtual machine other than the migrated processes.

Abstract: Guests, such as virtual machines, that are running on a host hardware platform are selectively descheduled when an idling condition is detected. An example of the idling condition is that the guest has been executing instructions in an idle loop for more than a threshold period. Guest instructions may be evaluated for the idling condition in conjunction with binary translation.

Abstract: Virtual machines that utilize pass-through devices are migrated from a source host computer to a destination host computer. During preparation for migration, the pass-through device is substituted with an emulation handler that simulates the pass-through device experiencing errors. Upon successful migration, an error reporting signal is triggered to cause the device driver in the virtual machine to initiate a reset of the pass-through device at the destination host computer, upon which the pass-through device is mapped to the migrated virtual machine.

Abstract: One embodiment of the present invention includes a method for maintaining a shadow page table in at least partial correspondence with guest page mappings of a guest computation. The method marking with a traced write indication at least those entries of the shadow page table that map physical memory locations which themselves encode the guest page mappings, the marking identifying, for a hardware facility, a subset of memory access targets for which updates are to be recorded in a guest write buffer accessible to the virtualization system. Responsive to a coherency-inducing operation of the guest computation, the method reads from the guest write buffer and introduces corresponding updates into the shadow page table.

Abstract: Some embodiments of the present invention include an execution unit of a processor and a memory management unit interposed between the execution unit and an interface to memory suitable for storage of both guest page tables maintained by a guest operating system and shadow page tables maintained generally in correspondence with the guest page tables by virtualization software. The memory management unit is configured to walk in-memory data structures that encode the shadow page tables, to access entries of the shadow page tables and, based thereon or on a cached representation of page mappings therein, to perform virtual-to-physical address translations relative to memory targets of instructions executed by the execution unit.

Abstract: Various embodiments of the present invention provide for enhanced calendaring functionality in a collaboration suite application. A mini-calendar display in different views of the collaboration suite application provide for an easy way to view, edit and/or add appointments without needing to open of the calendar in the collaboration suite application. Email messages can be dragged onto days in the mini-calendar to create meeting proposals. Enhanced UI allows for different meetings being having different appearances based on whether they have been accepted, rejected, etc. Multiple calendars can be viewed simultaneously and their cumulative availability for any time slot can be easily seen via a calendar thermometer. Requests for sharing of calendars can be communicated via email messages, and they can be seamlessly responded to within the email message itself.