Description

Add discover_boot_options() helper to patina_boot::helpers that reads UEFI BootOrder and Boot#### variables to build a BootConfig from standard UEFI boot options.

This enables any BootOrchestrator implementation that consumes BootConfig to use UEFI-compliant boot variables instead of requiring platforms to hardcode device paths. The function:

• Reads BootOrder to determine boot attempt order
• Parses each Boot#### EFI_LOAD_OPTION structure to extract device paths
• Filters out inactive boot options (LOAD_OPTION_ACTIVE)
• Gracefully skips unreadable or malformed entries
• Returns a populated BootConfig with discovered devices in priority order

• Impacts functionality?
• Impacts security?
• Breaking change?
• Includes tests?
• Includes documentation?

How This Was Tested

• Unit tests covering: single/multiple boot options, inactive option filtering, unreadable variable handling, truncated load option data, empty BootOrder, and hex variable name generation
• Integration tested with patina-dxe-core-qemu feature/patina-boot on QEMU Q35 — full boot to UEFI Shell 2.0

Integration Instructions

Platforms can call discover_boot_options() with runtime services to automatically populate a BootConfig from UEFI boot variables instead of constructing device paths manually. This works with any BootOrchestrator implementation that accepts a BootConfig:

let config = discover_boot_options(&runtime_services)?;
add.component(BootDispatcher::new(SimpleBootManager::new(config)));