Patent ID: 7454787

Claim:
A method, within a computer system containing one or more CPUs, for securing direct access, by a non-trusted processing entity external to the one or more CPUs, to a resource through a system bus, the method comprising: providing a bridge device external to the one or more CPUs that includes access-authorization logic and that interconnects the non-trusted processing entity external to the one or more CPUs with the system bus and, through the system bus, to the resource; upon receiving, by the bridge device, a resource-access request from the non-trusted processing entity external to the one or more CPUs specifying a portion of the resource, using the access-authorization logic to determine whether or not the access request is authorized; when bridge device determines that the non-trusted processing entity external to the one or more CPUs is authorized to access the portion of the resource, providing access to the portion of the resource to the non-trusted processing entity external to the one or more CPUs; and when the bridge device determines that the non-trusted processing entity external to the one or more CPUs is not authorized to access the portion of the resource, returning to the non-trusted processing entity external to the one or more CPUs an access error.