Abstract: Disclosed herein are systems and method for live migration of a guest OS, the method comprising: interrupting execution of the guest OS in the hypervisor on a source computing device, transferring a state of the guest OS from the hypervisor on the source computing device to a hypervisor on a target computing device, and resuming execution of the guest OS in the hypervisor on the target computing device without waiting for completion of pending I/O requests on the source, wherein the pending I/O requests are generated by the guest OS in the hypervisor on the source and have not been completed before the interruption of execution of the guest OS, and wherein after resuming execution of the guest OS, the guest OS in the hypervisor on the target computing device is allowed to generate new I/O requests without waiting for completion of pending I/O requests on the source computing device.

Abstract: Disclosed herein are systems and method for generating a guest Operating System (OS) crash dump. In one aspect, an exemplary method comprises, obtaining information about a guest physical memory and a state of a guest CPU, determining guest page tables including a data structure for mapping between the guest physical memory and guest virtual pages using registers of the guest CPU, identifying an interrupt handler and determining an address of the interrupt handler using the guest page tables and the registers of guest CPU, finding a location of a kernel image in memory by scanning virtual addresses backward starting from the interrupt handler until a beginning of an executable kernel module is found, identifying and fetching debug symbols, determining system task descriptors using the debug symbols, determining debugger relevant data using the debug symbols, and generating the crash dump header using the system task descriptors and the debugger relevant data.

Abstract: A method for zeroing guest memory of a VM during boot up, includes the guest OS attempts to set a page to zero. A page fault is generated and is handled by the hypervisor. The page is mapped by the hypervisor to a page in host memory, and is given to the guest. The guest OS attempts to set the next page to zero. Another page fault is generated the hypervisor unmaps the host memory page, and the second page is mapped to the same page. The hypervisor then gives the page to the guest, which contains all zeros. The process is repeated for remaining pages of the guest memory.

Abstract: A system for memory management for Virtual Machines (VMs), including a host computer system running a host operating system (OS); at least two Virtual Machines (VMs) running on the host computer system, wherein each of the VMs has a Guest OS supporting a guest file system with execution-in-place that allows code execution without an intermediate buffer cache; a hypervisor configured to control the VMs; and a thin provisioning block device configured to store shared pages and formed of at least one delta file. The hypervisor is configured to receive a page fault, and to read the shared pages from the thin provisioning block device. The Guest OS executes the file that is stored on the thin provisioning block device.

Abstract: Method for avoiding Guest I/O timeout, including generating a request to an I/O device in a Guest Operating System (GOS) running inside a VM; setting a VM timeout deadline; in a hypervisor, setting a supervisory timeout deadline for the I/O device to respond that is shorter than the VM timeout deadline; if no response is received before expiration of the supervisory timeout deadline, pausing the GOS; freezing system time of the GOS; activating a handler for the I/O device response in the hypervisor; upon receipt of the response prior to the supervisory timeout deadline, forwarding the response to the GOS, unpausing the GOS, unfreezing the system time of the GOS; upon receipt of the response after the supervisory timeout deadline, and after the GOS is unpaused by the hypervisor, the Guest OS receives the response from the hardware device; and if no response is received, the GOS is kept paused.

Abstract: System for working with shared memory includes a plurality of contexts, each having executable processes writing and reading data; a ring buffer in the shared memory for writing and reading data by the contexts; a software primitive manages access attempts by the contexts to the ring buffer. Each context, upon writing to the ring buffer, is allocated an amount of space up to a maximum available at that moment. The software primitive guarantees consistency of the data written to the ring buffer. The software primitive permits simultaneous writing into the buffer by multiple contexts. After finishing writing to the buffer, the context updates a state of the buffer by decrementing the count of the active writers and/or by shifting the permitting pointers for communicating with writers and readers. A context can read from the buffer only data is marked as valid for reading by the context that wrote that data.

Abstract: Method for avoiding Guest I/O timeout, including generating a request to an I/O device in a Guest Operating System (GOS) running inside a VM; setting a VM timeout deadline; in a hypervisor, setting a supervisory timeout deadline for the I/O device to respond that is shorter than the VM timeout deadline; if no response is received before expiration of the supervisory timeout deadline, pausing the GOS; freezing system time of the GOS; activating a handler for the I/O device response in the hypervisor; upon receipt of the response prior to the supervisory timeout deadline, forwarding the response to the GOS, unpausing the GOS, unfreezing the system time of the GOS; upon receipt of the response after the supervisory timeout deadline, and after the GOS is unpaused by the hypervisor, the Guest OS receives the response from the hardware device; and if no response is received, the GOS is kept paused.

Abstract: System for working with shared memory includes a plurality of contexts, each having executable processes writing and reading data; a ring buffer in the shared memory for writing and reading data by the contexts; a software primitive manages access attempts by the contexts to the ring buffer. Each context, upon writing to the ring buffer, is allocated an amount of space up to a maximum available at that moment. The software primitive guarantees consistency of the data written to the ring buffer. The software primitive permits simultaneous writing into the buffer by multiple contexts. After finishing writing to the buffer, the context updates a state of the buffer by decrementing the count of the active writers and/or by shifting the permitting pointers for communicating with writers and readers. A context can read from the buffer only data is marked as valid for reading by the context that wrote that data.

Abstract: A method and system for emulation of super speed external devices in a virtual machine (VM), including checking the ability of the VM Guest OS to support the super speed external device. If the super speed device is not supported by the Guest OS, device metadata is substituted by the metadata of the devices supported by the Guest OS. The method replaces the metadata of a new external device by the metadata of an older or different (supported) device. A VM acquires a descriptor of the external device configuration and “patches” the device by replacing device version data from a new device version to an older (or different) device.

Abstract: A computing system includes a physical server having a single instance of an operating system; and a plurality of virtual environments running on the physical server and directly supported by the single instance of the operating system. Each virtual environment responds to requests from users and appears to the users as a stand-alone server having its own instance of the operating system. Each virtual environment has a plurality of objects associated with it and supported by the operating system. Some of the objects are private and other objects are shared between multiple virtual environments. One virtual environment cannot access private objects of another virtual environment.