1. A non-transitory computer-readable storage medium storing instructions for supplying a guest operating system to a virtual machine, which when executed by one or more processors, cause: in response to receiving data that identifies where, within a guest operating system, sensitive data is located, updating a data structure to identify where the sensitive data is located within the guest operating system; in response to receiving, from a requestor, a request to access a portion of the guest operating system, determining whether the data structure indicates that the requested portion of the guest operating system contains sensitive data; and upon determining that the requested portion of the guest operating system does contain sensitive data, informing the requestor that a disk fault has occurred to cause the requestor to abort the request.