CPUID

Selector-dependent register interface

CPUID returns identification and feature information in EAX, EBX, ECX, and EDX. Model the instruction separately from each observation. Reference: [Intel architecture programming reference](https://www.intel.com/content/dam/develop/external/us/en/documents/architecture-instruction-set-extensions-programming-reference-737410.pdf).

1. Does the registry's originating record identify the x86 instruction rather than the CPUID company or a utility? definition
2. Which EAX leaf and applicable ECX subleaf produced this response? measurement

Range and subleaf validity

Standard and extended function ranges require explicit handling; retain range discovery and leaf-specific enumeration rules. Reference: [AMD CPUID specification](https://www.amd.com/content/dam/amd/en/documents/archived-tech-docs/design-guides/25481.pdf).

1. What supported ranges and maximum selectors were observed? measurement
2. Which documented validity and termination rules apply to this leaf's subleaves? boundary

Family, model, and stepping interpretation

Processor signature interpretation requires documented family and model decoding rules. Reference: [Intel CPUID enumeration guidance](https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/technical-documentation/cpuid-enumeration-and-architectural-msrs.html).

1. Which raw signature fields and vendor-specific rules support the decoded family, model, and stepping? provenance
2. What evidence would be needed before associating this report with one physical asset? boundary

Traceable bit decoding

Each decoded claim should identify its leaf, subleaf, register, bit or field, and supporting specification; retain unrecognized fields without assigning invented meanings.

1. Which document revision and field definition justify this decoded claim? provenance
2. Is this field defined, reserved, or outside the decoder's supported scope? boundary

Usable feature decision

Record the complete prerequisite check for a proposed code path, including applicable operating system extended-state enablement, rather than treating one feature bit as sufficient.

1. Which CPUID fields and non-CPUID state checks does this code path require? action
2. What fallback should the agent select when a prerequisite is absent or unverified? action

Structural report interpretation

For available topology and cache queries, retain raw fields and decoding formulas, and separate the reported structure from operating system availability and measured performance.

1. Which queries and formulas support the reported cache dimensions or topology relationships? measurement
2. How does the reported structure relate to the processors available to this process? boundary

Report origin and mediation

Record whether the report was collected directly, supplied by another tool, or obtained inside a virtual environment, and leave host hardware conclusions unresolved where mediation is unknown.

1. Which collector, logical processor or vCPU, and execution environment produced the report? provenance
2. What evidence establishes whether the reported capabilities reflect a guest-visible configuration or physical hardware? boundary

Decision-specific evidence coverage

Record missing queries, collection failures, and differences between processor observations; define revalidation conditions for decisions that depend on those reports.

1. Does the report cover every selector and execution context required by the proposed decision? measurement
2. Which changes to processor placement, virtual machine configuration, or system state require recollection? action

Check these first

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these check these first hold for the sense of CPUID this model covers, and on what evidence? provenance

Identifiers and schemes

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these identifiers and schemes hold for the sense of CPUID this model covers, and on what evidence? provenance

Standards and regulation

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these standards and regulation hold for the sense of CPUID this model covers, and on what evidence? provenance

Real-world use

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these real-world use hold for the sense of CPUID this model covers, and on what evidence? provenance

Typical measurements

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these typical measurements hold for the sense of CPUID this model covers, and on what evidence? provenance

Failure modes and hazards

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these failure modes and hazards hold for the sense of CPUID this model covers, and on what evidence? provenance

Neighbouring kinds and how to tell them apart

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these neighbouring kinds and how to tell them apart hold for the sense of CPUID this model covers, and on what evidence? provenance