Secure Guest Large-Page Translation Through Small-Page Validation
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Solution Overview
Problem
Existing virtual machine management approaches limit secure guests to small pages due to security and performance concerns, preventing the use of larger pages that could enhance processing efficiency.
Innovation Solution
A secure interface control, such as an Ultravisor, maintains a counter for each large page to ensure all small pages belonging to a secure guest are correctly aligned and meet security requirements before enabling large page translations, done transparently to the host and guest.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If secure guests use small pages only, then security requirements are met, but address translation speed and cache performance deteriorate
Solution Approach 1:
The patent segments the large page validation process into individual small page import checks, maintaining security by verifying each small page while enabling large page translations. The secure interface control divides the large page into multiple small pages and validates each one independently before allowing the large page to be used for address translation.
Solution Approach 2:
The patent performs preliminary validation of all small pages comprising a large page before enabling large page translations. The secure interface control checks each small page's security requirements in advance, and only after all validations pass does it enable the large page for use, thus preventing security issues while improving performance.
2Reliability
If secure guests use small pages only, then security alignment is maintained, but processing efficiency and cache performance worsen
Solution Approach 1:
The patent dynamically adjusts the page translation mechanism based on validation results. Initially, only small pages are used for security validation, but after all small pages comprising a large page are validated, the system dynamically switches to allow large page translations, thus improving processing efficiency while maintaining security alignment.
Solution Approach 2:
The patent changes the page size parameter from small pages to large pages based on validation state. When a large page is fully validated, the system changes the translation parameter to use the larger page size for address translation, thereby improving cache performance and processing efficiency without compromising security.
3Speed
If host translation is enabled for large pages, then address translation speed improves, but security verification complexity increases
Solution Approach 1:
The patent introduces a secure interface control as an intermediary between the host and the secure guest memory. This intermediary component handles the complex security verification of small pages comprising large pages, managing the counter that tracks validation status and coordinating with the host to enable large page translations only when security requirements are met.
Solution Approach 2:
The patent implements a feedback mechanism through a counter that tracks the validation status of small pages. The secure interface control continuously monitors this counter and provides feedback to the host about whether all small pages are validated. Only when the counter indicates complete validation does the system enable large page translations, thus managing complexity through structured feedback.
4Reliability
If all small pages are validated before enabling large pages, then security is ensured, but processing time increases
Solution Approach 1:
The patent performs preliminary validation of small pages as they are imported, rather than waiting until all pages are fully loaded. The secure interface control checks each small page's security requirements immediately upon import and updates the counter accordingly, enabling large page translations as soon as all pages are validated, thus minimizing validation time while ensuring security.
Solution Approach 2:
The patent maintains continuous validation processing by checking small pages as they are imported rather than batch-processing them later. The secure interface control continuously monitors imports and updates validation status in real-time, ensuring that as soon as all small pages are validated, large page translations are enabled without unnecessary delays.
Data Source
AI summary
Computer program products, computer-implemented method, and computer systems include a trusted element enabling host translation for a large page for a given block of memory of a secure guest. The enabling can include executing, in a trusted computing environment, a call from a host to import a page to a memory of the secure guest. The trusted element can determine that a page virtual address matches a page corresponding absolute address and based on this determination can increase a counter associated with the large page; the counter indicates small pages comprising the large page imported to guest memories. When the counter indicates that all the small pages were imported and based on this determination, the trusted element determines if that all the small pages meet pre-defined security requirements and if they do, enables host translation for the large page for the given block of memory of the secure guest.