Access control mechanism controlling access to and logical purging of access register translation lookaside buffer (ALB) in a computer system
First Claim
1. An access control apparatus in a computer system, said computer system including storage, physical processors, logical processors (LP'"'"'s) which can operate in either a host or guest mode, access registers, an access-register translator (ART), an ART-lookaside buffer (ALB) for storing entries created by said logical processors, said access control apparatus comprising:
- a host ALBID register for storing an ALB identifier (ALBID) and an ALBID validity indicator for the host mode of the logical processor;
a guest ALBID register for storing an ALB identifier (ALBID) and an ALBID validity indicator for the most recent guest mode on the logical processor;
first means for generating and storing in said host ALBID register an ALB identifier (ALBID) and for marking valid said ALBID validity indicator in said host ALBID register when a host mode is initiated on said logical processor and when a logical purge is requested during the host mode by said logical processor;
second means for generating and storing in said guest ALBID register an ALB identifier (ALBID) and for marking valid said ALBID validity indicator in said guest ALBID register when a guest mode is first initiated on said logical processor and when a logical purge is requested during a guest mode by said logical processor;
third means for storing in each ALB entry the host ALBID in said host ALBID register when an ALB entry is made in said ALB by said logical processor when said logical processor is in said host mode;
fourth means for storing in each ALB entry the guest ALBID in said guest ALBID register when an ALB entry is made in said ALB by said logical processor when said logical processor is in said guest mode;
fifth means for permitting access by the logical processor while in the host mode to an ALB entry in said ALB when said ALBID in said ALB entry matches the ALBID stored in said host ALBID register and the valid indicator in said ALBID host register is marked valid; and
sixth means for permitting access by the logical processor while in the guest mode to an ALB entry in said ALB when said ALBID in said ALB entry matches the ALBID stored in said guest ALBID register and the valid indicator in said ALBID guest register is mark valid.
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Abstract
An access control apparatus in a computer system for controlling access to an ALB. A host ALBID register and a guest ALBID register is provided for storing a host and a guest ALB identifier (ALBID) and a host and a guest ALBID validity indicator. Control State Software generates and stores the host and guest ALBIDs in the host and guest ALBID registers and marks valid the host and guest ALBID validity indicator whenever a host or guest mode is initiated or a logical purge is requested by a logical processor and for storing the host or guest ALBID stored in the host and guest ALBID registers when an ALB entry is made in the ALB by a logical processor. Access to an ALB entry by a logical processor is permitted when the logical processor is in the host mode if the ALBID in the ALB entry matches the host ALBID stored and the valid indicator is marked valid in the host ALBID register and when the logical processor is in the guest mode if the ALBID in the ALB entry matches the guest ALBID stored and the valid indicator is marked valid in the guest ALBID register. A host logical purge is accomplished by marking invalid the host and guest validity indicators in the host and guest ALBID registers. A guest Logical purge is accomplished by marking invalid the guest validity indicator in the guest ALBID register.
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Citations
13 Claims
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1. An access control apparatus in a computer system, said computer system including storage, physical processors, logical processors (LP'"'"'s) which can operate in either a host or guest mode, access registers, an access-register translator (ART), an ART-lookaside buffer (ALB) for storing entries created by said logical processors, said access control apparatus comprising:
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a host ALBID register for storing an ALB identifier (ALBID) and an ALBID validity indicator for the host mode of the logical processor; a guest ALBID register for storing an ALB identifier (ALBID) and an ALBID validity indicator for the most recent guest mode on the logical processor; first means for generating and storing in said host ALBID register an ALB identifier (ALBID) and for marking valid said ALBID validity indicator in said host ALBID register when a host mode is initiated on said logical processor and when a logical purge is requested during the host mode by said logical processor; second means for generating and storing in said guest ALBID register an ALB identifier (ALBID) and for marking valid said ALBID validity indicator in said guest ALBID register when a guest mode is first initiated on said logical processor and when a logical purge is requested during a guest mode by said logical processor; third means for storing in each ALB entry the host ALBID in said host ALBID register when an ALB entry is made in said ALB by said logical processor when said logical processor is in said host mode; fourth means for storing in each ALB entry the guest ALBID in said guest ALBID register when an ALB entry is made in said ALB by said logical processor when said logical processor is in said guest mode; fifth means for permitting access by the logical processor while in the host mode to an ALB entry in said ALB when said ALBID in said ALB entry matches the ALBID stored in said host ALBID register and the valid indicator in said ALBID host register is marked valid; and sixth means for permitting access by the logical processor while in the guest mode to an ALB entry in said ALB when said ALBID in said ALB entry matches the ALBID stored in said guest ALBID register and the valid indicator in said ALBID guest register is mark valid. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An access control apparatus in a computer system, said computer system including storage, physical processors, logical processors (LP'"'"'s) which can operate in either a host or guest mode, access registers, an access-register translator (ART), an ART-lookaside buffer (ALB) for storing entries created by said logical processors, said access control apparatus comprising:
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a host ALBID register for storing an ALB identifier (ALBID) and an ALBID validity indicator for the host mode of the logical processor; a guest ALBID register for storing an ALB identifier (ALBID) and an ALBID validity indicator for the most recent guest mode on the logical processor; Control State Software (CSSW) stored in said storage performing the functions of; generating and storing in said host ALBID register an unique ALB identifier (ALBID) and for marking valid said ALBID validity indicator in said host ALBID register when a host mode is initiated on said logical processor and when a logical purge is requested during the host mode by said logical processor; generating and storing in said guest ALBID register an unique ALB identifier (ALBID) and for marking valid said ALBID validity indicator in said guest ALBID register when a guest mode is first initiated on said logical processor and when a logical purge is requested during a guest mode by said logical processor; storing in each ALB entry the host ALBID in said host ALBID register when an ALB entry is made in said ALB by said logical processor when said logical processor is in said host mode; and storing in each ALB entry the guest ALBID in said guest ALBID register when an ALB entry is made in said ALB by said logical processor when said logical processor is in said guest mode; first means for permitting access by the logical processor while in said host mode to an ALB entry in said ALB when said ALBID in said ALB entry matches the ALBID stored in said host ALBID register and the valid indicator in said ALBID host register is marked valid; and second means for permitting access by the logical processor while in the guest mode to an ALB entry in said ALB when said ALBID in said ALB entry matches the ALBID stored in said guest ALBID register and the valid indicator in said ALBID guest register is marked valid. - View Dependent Claims (9, 10, 11, 12, 13)
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Specification