Patent ID: 6345347
Filing Date: 2002-02-05
Classification: G06F

Abstract:
In a computer system in which a software application accesses a system memory by communicating directly with a hardware device, a method for protecting addresses in the system memory from improper access, comprising:in an initialization stage: assigning a register of the hardware device to the application; generating in the hardware device a protection block, which block is used thereafter by the device to control access by the application to the system memory; storing in the protection block a first key corresponding to a physical address of the register; and assigning a handle to the application that refers to the protection block; and in operation of the application: conveying a command from the application via the register to access the system memory, the command including the handle; responsive to the command, generating in the hardware device a second key corresponding to the physical address of the register; responsive to the handle, comparing the first and second keys; and allowing the application to access the system memory only if the first and second keys match in a predetermined manner.