The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 05, 2011
Filed:
Dec. 19, 2003
Marcus Peinado, Bellevue, WA (US);
Paul England, Bellevue, WA (US);
Bryan Mark Willman, Kirkland, WA (US);
Yuqun Chen, Bellevue, WA (US);
Andrew John Thornton, Seattle, WA (US);
Marcus Peinado, Bellevue, WA (US);
Paul England, Bellevue, WA (US);
Bryan Mark Willman, Kirkland, WA (US);
Yuqun Chen, Bellevue, WA (US);
Andrew John Thornton, Seattle, WA (US);
Microsoft Corporation, Redmond, WA (US);
Abstract
Plural guest operating systems run on a computer, where a security kernel enforces a policy of isolation among the guest operating systems. An exclusion vector defines a set of pages that cannot be accessed by direct memory access (DMA) devices. The security kernel enforces an isolation policy by causing certain pages to be excluded from direct access. Thus, device drivers in guest operating systems are permitted to control DMA devices directly without virtualization of those devices, while each guest is prevented from using DMA devices to access pages that the guest is not permitted to access under the policy.