A coherency driven expansion to the PCIe transaction layer is disclosed. In an exemplary aspect, a coherency agent is added to the PCIe system to support relaxed integrity models so that memory can be used in the PCIe system. Specifically, the endpoint can request ownership of a portion of the memory to read from and write to memory. The coherency agent allocates an address range including the requested part. The requesting endpoint copies the contents of the memory corresponding to the allocated address range into the local endpoint memory and locally performs the read and write operations. The owning endpoint may provide an updated snapshot of the copied memory content upon request. Ownership of the address range returns to the root complex when the use of the copied memory contents is completed or when a request is issued from the coherency agent and the end point stores the updated contents in the address Send back to the range.
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