Virtual ISA Translation for Deprecated Instruction Support
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Deprecating instruction set architecture (ISA) features poses challenges as existing software may no longer function on new ISAs, necessitating a solution to manage unsupported or deprecated features in virtualized environments.
Innovation Solution
An apparatus and method for managing unsupported ISA features in virtualized environments by translating deprecated instructions into simpler native instructions, enabling seamless execution without dedicated hardware or microcode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deprecated ISA features are removed to reduce attack surfaces and simplify validation, then security and validation complexity improve, but existing software compatibility deteriorates
Solution Approach 1:
The patent introduces a deprecated instruction processor as an intermediary layer between the core processor and deprecated ISA features. This mediator translates deprecated instructions into supported instructions, allowing the processor to maintain security by removing deprecated features while preserving software compatibility through automatic translation. The intermediary handles legacy instruction translation without requiring the core processor to directly support deprecated features.
2Adaptability or versatility
If dedicated hardware or microcode is added to support deprecated features, then software compatibility improves, but device complexity increases
Solution Approach 1:
Instead of adding dedicated hardware or microcode to the core processor, the patent implements a software-based deprecated instruction processor that acts as an intermediary. This approach maintains software compatibility through instruction translation while avoiding the increase in processor hardware complexity. The translation layer is implemented as software rather than hardware, keeping the core processor simple.
3Speed
If deprecated instructions are directly executed on new ISA, then execution speed improves, but software compatibility deteriorates
Solution Approach 1:
The deprecated instruction processor serves as an intermediary that automatically translates deprecated instructions into supported instructions before execution. This translation happens transparently to the executing software, maintaining compatibility while allowing the core processor to execute only supported instructions at optimal speeds. The intermediary handles the conversion without requiring software modification.
4Adaptability or versatility
If instruction translation is implemented, then software compatibility improves, but processing overhead increases
Solution Approach 1:
The patent implements preliminary action by having the deprecated instruction processor translate deprecated instructions into supported instructions before they reach the core processor for execution. This pre-translation approach allows the core processor to execute instructions directly without runtime translation overhead, as the conversion is completed in advance by the intermediary layer.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
Apparatus and method supporting deprecated instructions. One embodiment comprises: a plurality of cores, each core comprising a current microarchitecture to execute instructions and process data, the current microarchitecture including virtual execution environment support for a hypervisor running at a first privilege level and one or more virtual machines running at a second privilege level, the microarchitecture further including support for executing deprecated instructions associated with a prior microarchitecture. At least one core comprising: a decoder to specify one or more microoperations corresponding to each of the instructions; execution circuitry to execute the corresponding microoperations; wherein either a first type or a second type of virtual machine exit is supported. Responsive to the first type of virtual machine exit, the hypervisor performs a first emulation without the partial hardware support. Responsive to the second type of virtual machine exit, the hypervisor perform a second emulation using the partial hardware support.