Shared memory between child and parent partitions
A mechanism for the creation of a shared memory aperture between modes in a parent and child partition is described. The shared memory aperture can be created between any memory mode between the guest and any host. For example, a shared memory aperture can be created between the kernel mode on the child partition and the user mode on the parent partition.
1. A method of transferring data between virtual machine partitions, the method comprising:
sending by a first virtual machine partition to a second virtual machine partition a request for allocation of memory, wherein the allocation indicates a maximum buffer size for transferred data;
mapping the requested memory allocation;
allocating the requesting memory in a shared memory aperture between modes in the first and second virtual machine partitions; and
transferring data between the first and second virtual machine partitions using the shared memory aperture.
2. The method of claim 1 , wherein the first virtual machine partition is a child partition and the second virtual machine partition is a parent partition.
3. The method of claim 2 , wherein the modes comprise either a kernel mode or a user mode.
4. The method of claim 3 , further comprising opening a virtualization service client (VSC) device object and sending a control message to a VSC driver requesting that the user mode or kernel mode buffer allocated in the child partition be shared with a parent partition buffer.
5. The method of claim 4 , wherein the VSC driver creates a memory descriptor list (MDL) for the buffer allocated in the child partition's guest operating system (OS) memory space.
6. The method of claim 5 , wherein the VSC driver converts the MDL to a guest physical address descriptor list (GPADL) that describes system pages that the buffer has been allocated by a hypervisor.
7. The method of claim 2 , wherein the data comprises graphics data representative of a client screen in a remote presentation session.
8. The method of claim 7 , the graphics data is rendered by a virtualized graphics accelerator executing in the parent partition.
9. The method of claim 1 , wherein the maximum buffer size is negotiated between the first and second partitions.
10. The method of claim 1 , wherein the shared memory aperture is created using a software library.
11. The method of claim 1 , further comprising closing the shared memory aperture by unlocking, unmapping, and releasing the shared memory aperture.
12. A system for transferring data between virtual machine partitions, comprising:
a computing device comprising at least one processor;
a memory communicatively coupled to said processor when said system is operational; said memory having stored therein computer instructions that upon execution by the at least one processor cause:
sending by a first virtual machine partition to a second virtual machine partition a request for allocation of memory, wherein the allocation indicates a maximum buffer size for transferred data;
mapping the requested memory allocation;
allocating the requested memory in a shared memory aperture between modes in the first and second virtual machine partitions; and
transferring data between the first and second virtual machine partitions using the shared memory aperture.
13. The system of claim 12 , wherein the first virtual machine partition is a child partition and the second virtual machine partition is a parent partition.
14. The system of claim 13 , wherein the modes comprise either a kernel mode or a user mode.
15. The system of claim 12 , wherein the maximum buffer size is negotiated between the first and second partitions.
16. The system of claim 12 , wherein the shared memory aperture is created using a software link library.
17. A computer readable storage medium storing thereon computer executable instructions for transferring data between virtual machine partitions, said instructions for:
sending by a child virtual machine partition to a parent virtual machine partition a request for allocation of memory, wherein the allocation indicates a maximum buffer size for transferred data;
mapping the requested memory allocation;
allocating the requesting memory in a shared memory aperture between modes in the child and parent virtual machine partitions; and
transferring data between the child and parent virtual machine partitions using the shared memory aperture.
18. The computer readable storage medium of claim 17 , wherein the modes comprise either a kernel mode or a user mode.
19. The computer readable storage medium of claim 17 , wherein the maximum buffer size is negotiated between the child and parent partitions.
20. The computer readable storage medium of claim 17 , wherein the data comprises graphics data representative of a client screen in a remote presentation session and the graphics data is rendered by a virtualized graphics accelerator executing in the parent partition.