Dynamic Guest Virtual Machine Identifier Allocation

Patent metadata

Field	Value
Publication number	US-2016246649-A1
Application number	US-201514629945-A
Country	US
Kind code	A1
Filing date	Feb 24, 2015
Priority date	Feb 24, 2015
Publication date	Aug 25, 2016
Grant date	—

Abstract

An example method of updating a virtual machine (VM) identifier (ID) stored in a memory buffer allocated from guest memory includes supplying firmware to a guest running on a VM that is executable on a host machine. The firmware includes instructions to allocate a memory buffer. The method also includes obtaining a buffer address of the memory buffer. The memory buffer is in guest memory and stores a VM ID that identifies a first instance of the VM. The method further includes storing the buffer address into hypervisor memory. The method also includes receiving an indication that the VM ID has been updated. The method further includes using the buffer address stored in hypervisor memory to update the VM ID.

First claim

What is claimed is:

1 . A method of updating a virtual machine identifier (ID) stored in a memory buffer allocated from guest memory, comprising:
supplying, by a hypervisor, firmware to a guest running on a virtual machine that is executable on a host machine, wherein the firmware includes instructions to allocate a memory buffer; obtaining a buffer address of the memory buffer allocated from guest memory, wherein the memory buffer is in guest memory and stores a virtual machine ID that identifies a first instance of the virtual machine; storing the buffer address into hypervisor memory; receiving an indication that the virtual machine ID has been updated; and using the buffer address stored in hypervisor memory to update the virtual machine ID.

2 . The method of claim 1 , wherein the firmware further includes instructions to generate an Advanced Configuration and Power Interface (ACPI) data structure including an ACPI method that passes the buffer address of the memory buffer.

3 . The method of claim 2 , wherein the ACPI data structure is an ACPI table.

4 . The method of claim 2 , further including:
executing, at the guest, the instructions included in the firmware, wherein execution of the instructions causes the buffer address of the memory buffer to be passed to the hypervisor.

5 . The method of claim 4 , wherein the ACPI data structure includes a synthetic device including the ACPI method, and wherein the executing is in response to initialization of the synthetic device.

6 . The method of claim 4 , wherein the executing is in response to invocation of the ACPI method.

7 . The method of claim 4 , wherein the executing the instructions includes invoking the ACPI method, and wherein the invoking the ACPI method causes the buffer address to be written to a non-present memory address.

8 . The method of claim 1 , further including:
detecting an event that causes the first virtual machine ID to change to a second virtual machine ID.

9 . The method of claim 1 , wherein the using includes retrieving the buffer address from hypervisor memory and storing a second virtual machine ID that identifies a second instance of the virtual machine into the buffer address.

10 . The method of claim 1 , wherein the buffer address is a non-fixed memory address.

11 . A system for updating a virtual machine identifier (ID) stored in a memory buffer allocated from guest memory, comprising:
a hypervisor that supplies firmware to a guest running on a virtual machine that is executable on a host machine, obtains a buffer address of a memory buffer allocated from guest memory, and stores the buffer address into hypervisor memory, wherein the firmware includes instructions to allocate the memory buffer, and the memory buffer is in guest memory and stores a virtual machine ID that identifies a first instance of the virtual machine, and wherein in response to receiving an indication that the virtual machine ID has been updated, the hypervisor uses the buffer address stored in the hypervisor memory to update the virtual machine ID.

12 . The system of claim 11 , wherein the firmware further includes instructions to generate an Advanced Configuration and Power Interface (ACPI) data structure including an ACPI method that passes the buffer address of the memory buffer.

13 . The system of claim 12 , wherein the ACPI data structure is an ACPI table.

14 . The system of claim 12 , wherein the guest executes the instructions included in the firmware, and wherein execution of the instructions causes the buffer address of the memory buffer to be passed to the hypervisor.

15 . The system of claim 14 , wherein the ACPI data structure includes a synthetic device including the ACPI method, and wherein the executing is in response to initialization of the synthetic device.

16 . The system of claim 14 , wherein the guest executes the instructions in response to invocation of the ACPI method.

17 . The system of claim 11 , wherein the hypervisor detects an event that causes the first virtual machine ID to change to a second virtual machine ID.

18 . The system of claim 11 , wherein the hypervisor retrieves the buffer address from hypervisor memory and stores a second virtual machine ID that identifies a second instance of the virtual machine into the buffer address.

19 . The system of claim 11 , wherein the buffer address is a non-fixed memory address.

20 . A machine-readable medium comprising a plurality of machine-readable instructions that when executed by one or more processors is adapted to cause the one or more processors to perform a method comprising:
supplying, by a hypervisor, firmware to a guest running on a virtual machine that is executable on a host machine, wherein the firmware includes instructions to allocate a memory buffer; obtaining a buffer address of the memory buffer, wherein the memory buffer is in guest memory and stores a virtual machine ID that identifies a first instance of the virtual machine; storing the buffer address into hypervisor memory; receiving an indication that the virtual machine ID has been updated; and using the buffer address stored in hypervisor memory to update the virtual machine ID.

Assignees

• Red Hat Israel Ltd

Inventors

• Tsirkin Michael
• Hammer Gal

Classifications

• G06F8/654

  using techniques specially adapted for alterable solid state memories, e.g. for EEPROM or flash memories · CPC title

• G06F9/5016 Primary

  the resource being the memory · CPC title

• G06F9/45558 Primary

  Hypervisor-specific management and integration aspects · CPC title

• G06F12/1036

  for multiple virtual address spaces, e.g. segmentation (G06F12/1045 takes precedence) · CPC title

• G06F2212/152

  Virtualized environment, e.g. logically partitioned system · CPC title