Delivery of events from a virtual machine to host CPU using memory monitoring instructions

Patent metadata

Field	Value
Publication number	US-9256455-B2
Application number	US-201213681738-A
Country	US
Kind code	B2
Filing date	Nov 20, 2012
Priority date	Nov 20, 2012
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

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.

First claim

What is claimed is:

1. A method comprising:
executing, by a host central processing unit (CPU), a memory monitoring instruction to identify an address range;
receiving, by a virtual machine executing a guest, from a hypervisor executable by the host CPU, a notification identifying the identified address range writeable by a virtual central processing unit (VCPU) associated with the virtual machine to send an event to the host CPU;
receiving, by the virtual machine, an instruction to write to the identified address range for sending an event to the host CPU; and
writing, by the VCPU, data identifying an event for execution by the host CPU to the identified address range, without causing an exit to the hypervisor.

2. The method of claim 1 , wherein the identified address range comprises a protected portion not writeable by the VCPU.

3. The method of claim 1 , wherein the identified address range is dedicated for writing to by the VCPU.

4. The method of claim 1 , wherein writing to the identified address range comprises executing an atomic instruction.

5. The method of claim 1 , further comprising maintaining, by the virtual machine, an association between the identified address range and the host CPU.

6. The method of claim 1 , wherein the hypervisor maintains an assignment of a plurality of additional address ranges associated with the host CPU, wherein each of the plurality of additional address ranges is dedicated for writing to by a specific source type.

7. A non-transitory computer readable storage medium comprising instructions that, when executed by a host central processing unit (CPU), cause the host CPU to:
execute a memory monitoring instruction to identify an address range;
receive, by a virtual machine executing a guest from a hypervisor executable by the host CPU, a notification identifying the identified address range writeable by a virtual central processing unit (VCPU) associated with the virtual machine to send an event to the host CPU;
receive, by the virtual machine, an instruction to write to the identified address range for sending an event to the host CPU; and
write, by the VCPU, data identifying an event for execution by the host CPU to the identified address range, without causing an exit to the hypervisor.

8. The non-transitory computer readable storage medium of claim 7 , wherein the identified address range comprises a protected portion not writeable by the VCPU.

9. The non-transitory computer readable storage medium of claim 7 , wherein the identified address range is dedicated for writing to by the VCPU.

10. The non-transitory computer readable storage medium of claim 7 , wherein the data identifying the event for execution by the host CPU is written to the identified address range by an atomic instruction.

11. The non-transitory computer readable storage medium of claim 7 , the host CPU to maintain an association between the identified address range and the host CPU.

12. The non-transitory computer readable storage medium of claim 7 , wherein the hypervisor maintains an assignment of a plurality of additional address ranges associated with the host CPU, wherein each of the plurality of additional address ranges is dedicated for writing to by a specific source type.

13. A computer system comprising:
a memory; and
a host central processing unit (CPU) operatively coupled to the memory, the host CPU to:
execute a memory monitoring instruction to identify an address range;
receive, by a virtual machine, from a hypervisor executable by the host CPU, a notification identifying the identified address range writeable by a virtual central processing unit (VCPU) associated with the virtual machine to send an event to the host CPU;
receive an instruction to write to the identified address range for sending an event to the host CPU; and
write, by the VCPU of the virtual machine, data identifying an event for execution by the host CPU to the identified address range, without causing an exit to the hypervisor.

14. The computer system of claim 13 wherein the identified address range comprises a protected portion not writeable by the VCPU.

15. The computer system of claim 13 , wherein the identified address range is dedicated for writing to by the VCPU.

16. The computer system of claim 13 , the processing device to write to the identified address range by executing an atomic instruction.

17. The computer system of claim 13 , wherein the virtual machine maintains an association between the identified address range and the host CPU.

18. The computer system of claim 13 , wherein the hypervisor maintains an assignment of a plurality of additional address ranges associated with the host CPU, wherein each of the plurality of additional address ranges is dedicated for writing to by a specific source type.

Assignees

• Red Hat Israel Ltd
• Red Hat Isreal Ltd

Inventors

• Tsirkin Michael
• Kivity Avi
• Laor Dor

Classifications

• G06F9/45558 Primary

  Hypervisor-specific management and integration aspects · CPC title

• G06F2009/45587

  Isolation or security of virtual machine instances · CPC title