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:
Feb. 11, 2014
Filed:
Dec. 28, 2011
Naoya Hattori, Hadano, JP;
Toshiomi Moriki, Kokubunji, JP;
Yuji Tsushima, Hachioji, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The program attains compatibility of suppression of an overhead accompanying page exception handling in the case of operating a program whose amount of memory use is large on a virtual machine and suppression of the overhead accompanying page exception handling in the case of operating a first OS that has a function of making another OS run on a virtual machine. A VMM creates a shadow PT (Page Table) for prohibiting reading-writing of privileged memory that requires emulation of reading/writing by using a RSV-bit, and registers the shadow PT and the second PT that a second OS operating on the first OS has in an x86 compatible CPU equipped with page exception detecting function using two PT's. When a page exception occurs, the VMM refers to cause code of the page exception and, when a P field of the cause code is 0, determines immediately that emulation is unnecessary.