openhcl_boot: allocate private pool based on heuristics

[mattkur]

This re-appplies #2215, now that we've figured out the CI issues (I hope).

• vmm_tests: add large nvme relay tests
• test fix, pr feedback
• up the vm memory
• tests: correctly mark heavy and very_heavy tests as heavy and very_heavy
• Reapply "openhcl_boot: set aside private pool memory based on heuristics (openhcl_boot: set aside private pool memory based on heuristics #2215)" (Revert "openhcl_boot: set aside private pool memory based on heuristics (#2215)" #2339)

[github-actions]

⚠️ Unsafe Code Detected

This PR modifies files containing unsafe Rust code. Extra scrutiny is required during review.

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[Copilot]

Pull Request Overview

This PR introduces heuristics-based private pool memory allocation for OpenHCL's VTL2 DMA operations. The system now automatically calculates appropriate DMA pool sizes based on VP count and VTL2 memory size, eliminating the need for manual configuration in most cases.

• Adds lookup tables with predefined DMA hint configurations for release and debug builds
• Implements a new command-line interface OPENHCL_IGVM_VTL2_GPA_POOL_CONFIG supporting heuristics, explicit sizes, or disabling
• Refactors existing tests to use a structured parameter approach and adds new test cases validating various configurations

Reviewed Changes

Copilot reviewed 14 out of 15 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
openhcl/openhcl_boot/src/host_params/dt/dma_hint.rs	New module implementing DMA hint calculation with lookup tables and extrapolation logic
openhcl/openhcl_boot/src/cmdline.rs	Adds Vtl2GpaPoolConfig enum and parsing logic for the new configuration interface
openhcl/openhcl_boot/src/host_params/dt/mod.rs	Integrates the new heuristics into the topology initialization path
openhcl/openhcl_dma_manager/src/lib.rs	Adds logging for DMA manager initialization parameters
vmm_tests/vmm_tests/tests/tests/x86_64/openhcl_uefi.rs	Refactors tests to use NvmeRelayTestParams struct and adds multiple configuration test cases
vmm_tests/vmm_tests/tests/tests/x86_64/openhcl_linux_direct.rs	Disables private pool for a specific test validating VTL2 RAM allocation
vm/loader/manifests/*.json	Updates all manifest files to enable the new heuristics-based configuration
openhcl/openhcl_boot/Cargo.toml	Adds test dependencies for tracing support in unit tests
petri/src/vm/mod.rs	Adds Debug derive to ProcessorTopology struct

[Copilot]

This magic number represents 1 TiB (as stated in the comment), but the hex value appears incorrect. 1 TiB = 0x10000000000 (1024^4). The current value 0xFFFFFFFF00000 equals ~256 TiB - 1 MiB. Either the comment or the constant should be corrected for clarity.

Suggested change

	const MAX_DMA_HINT_MEM_SIZE: u64 = 0xFFFFFFFF00000;
	const MAX_DMA_HINT_MEM_SIZE: u64 = 0x10000000000;

[Copilot]

This constant value is incorrect. 0x10_0000 equals 1,048,576 in decimal, which is 1 MiB, not 0x10_0000 which appears to be trying to represent 1 MB. However, this seems to be intentional based on usage. The issue is that this test-scoped ONE_MB shadows and contradicts the module-scoped ONE_MB at line 99 which correctly defines it as 1024 * 1024. Using different values for the same constant name in different scopes is confusing and error-prone.

Suggested change

const ONE_MB: u64 = 0x10_0000;

[Copilot]

The Default derive will fail because &'static str does not have a sensible default value. This should use #[derive(Default)] with #[default] attributes on fields, or implement Default manually to provide an empty string.

[Copilot]

[nitpick] The parsing logic silently converts invalid numeric strings to 'Off' configuration. While documented in the comment, this behavior could mask configuration errors. Consider logging a warning when parse failures occur to help debug misconfigurations.

Suggested change

	let num = arg.as_ref().parse::<u64>().unwrap_or(0);
	// A size of 0 or failure to parse is treated as disabling
	// the pool.
	if num == 0 {
	Vtl2GpaPoolConfig::Off
	} else {
	Vtl2GpaPoolConfig::Pages(num)
	// Try to parse as u64, log a warning if parsing fails.
	match arg.as_ref().parse::<u64>() {
	Ok(num) => {
	if num == 0 {
	Vtl2GpaPoolConfig::Off
	} else {
	Vtl2GpaPoolConfig::Pages(num)
	}
	}
	Err(_) => {
	log!("Warning: Invalid VTL2 GPA pool config value '{}', falling back to 'off'.", arg.as_ref());
	Vtl2GpaPoolConfig::Off
	}