Patent ID: 8250252

Claim:
A system, comprising: a plurality of virtual machines executed by a computing system for sending and receiving information; and an adapter presented to the plurality of virtual machines as a shared hardware resource; wherein the adapter includes a direct memory access (DMA) module that is used for transferring control blocks to and from a computing system memory to an adapter memory, where the computing system memory has dedicated memory locations for each virtual machine to place the control blocks and the adapter memory has dedicated memory locations for storing the control blocks generated by each of the plurality of virtual machines; and wherein the DMA module stores a context for each virtual machine that includes a computing system memory address assigned to each of the virtual machines and a quality of service entry that is used to limit a number of available control blocks that are transferred for a given one of the virtual machines at any given time when a control block from another one of the virtual machines is available and there is storage space available to store the available control block for the other one of the virtual machines.