Abstract: A system and method for passing Direct Memory Access (DMA) configuration information from one device driver to another in order to initialize devices for DMA operations are provided. More specifically, a mechanism for passing information, identifying a DMA address space allocated to a child virtual device, from the child virtual device to the virtual I/O (VIO) bus is provided so that DMA operations may be initialized for the child virtual device via the VIO bus. With the system and method, the device driver of the child virtual device passes information regarding the DMAble address space of the child virtual device directly to the device driver of the VIO bus using one of a I/O control (IOCTL) interface and an operating system kernel service. This information is then used by the VIO bus device driver to setup the VIO bus for DMA operations from the child virtual device.

Abstract: A system and method for extending the use of the cross-memory descriptor in a server partition environment such that it may be used to describe another partition's memory, e.g., a client partition's memory (referred to hereafter as a “remote” memory), are provided. With the system and method, when an operating system in a logically partitioned computing system is initialized, operating system kernel services are invoked that examine a device tree of the computing system and generate an extended cross-memory descriptor that describes the local memory of another logical partition, which is a remote memory to the present logical partition. When an access to a remote memory is required to perform an operation, the operating system of the server partition uses the stored extended cross-memory descriptor to perform the remote memory access.