perf(quickemu): tune TCG translation cache and enable multithreaded TCG

[flexiondotorg]

• Add TCG-specific runtime optimisations in vm_boot for cross-architecture VMs
• Detect host RAM and set tb-size to 512 for hosts with >=16GB, otherwise 256
• Append -accel tcg,tb-size=${TCG_TB_SIZE},thread=multi to QEMU args
• Improve TCG translation cache behaviour and SMP performance for TCG guests

Type of change

• New feature (non-breaking change which adds functionality)

Checklist:

• I have performed a self-review of my code
• I have tested my code in common scenarios and confirmed there are no regressions

[cubic-dev-ai]

1 issue found across 1 file

Confidence score: 5/5

• Minor style consistency issue: TCG_TB_SIZE should be declared local like HOST_RAM_GB, but this is low severity and unlikely to affect behavior.
• Low-impact housekeeping only, so merge risk appears minimal.
• Pay close attention to quickemu - ensure TCG_TB_SIZE is declared local for consistency.

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="quickemu">

<violation number="1" location="quickemu:1681">
P3: `TCG_TB_SIZE` should be declared as `local` for consistency with `HOST_RAM_GB` and the codebase's pattern of using local variables in functions.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[flexiondotorg]

@cubic-dev-ai

[cubic-dev-ai]

@cubic-dev-ai

@flexiondotorg I have started the AI code review. It will take a few minutes to complete.

[cubic-dev-ai]

No issues found across 1 file

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.