[AI Generated] BugFix: Skip MSR Hyper-V platform-id test on arm64 (rdmsr/msr-tools is x86-only)

[johnsongeorge-w]

Problem

Msr.verify_hyperv_platform_id reads the Hyper-V guest OS id register using rdmsr (from msr-tools, backed by the x86 msr char-device driver). All three are x86-only. On arm64 there is no rdmsr instruction, msr-tools is not packaged (E: Unable to locate package msr-tools), and the msr driver does not exist.

Previously the test still attempted to install msr-tools on arm64, looped on retries (~100s wasted), and finally skipped with a misleading message. The arch map also contained an arm64 entry (0x00090002) that falsely implied rdmsr could read it — but that value is a Hyper-V synthetic register identifier read via the hypercall interface (HvGetVpRegisters), not an x86 MSR number.

Fix

• Detect arm64 early (right after Lscpu.get_architecture()) and skip with an accurate reason, before any msr-tools install attempt.
• Remove the misleading arm64 entry from HV_REGISTER_GUEST_OSID (the rdmsr offset map).
• Preserve the arm64 register knowledge in a comment for a future hypercall-based implementation.

Validation

Ran Msr.verify_hyperv_platform_id on a real arm64 VM (Standard_D2pds_v5, Ubuntu 22.04 arm64, hardware_platform aarch64):

• Result: SKIPPED with MSR platform-id test uses rdmsr/msr-tools (x86-only); on arm64 the register is read via hypercall, not rdmsr.
• 0 msr-tools retry-loop lines (was ~12 before the fix).
• Test body skips in microseconds; no wasted install retries.

No behavior change on x86 — the test runs exactly as before.

[Copilot]

Pull request overview

This PR updates the Msr.verify_hyperv_platform_id test to correctly handle arm64 guests where rdmsr/msr-tools (and the underlying x86 MSR mechanism) are not available, avoiding wasted retries and providing an accurate skip reason.

Changes:

• Skip verify_hyperv_platform_id early on CpuArchitecture.ARM64 with a precise explanation (hypercall-based register access required).
• Remove the arm64 entry from the HV_REGISTER_GUEST_OSID rdmsr-offset map and preserve the arm64 register value as a comment for future hypercall-based work.