libvirt: Switch to UEFI (and tpm2) by default

[cgwalters]

No description provided.

[gemini-code-assist]

Summary of Changes

Hello @cgwalters, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly updates the default virtual machine configuration for Libvirt by transitioning from legacy BIOS to UEFI firmware and enabling TPM 2.0 by default. It introduces new command-line parameters to allow users to explicitly select firmware types, including secure boot, and to disable TPM if needed. These changes aim to modernize virtualized environments, enhance security, and provide greater flexibility in VM setup.

Highlights

• Default UEFI Firmware: Libvirt VMs will now default to using UEFI firmware instead of legacy BIOS, modernizing the boot process.
• Secure Boot Support: Explicit support for UEFI Secure Boot has been added, allowing VMs to be configured with enhanced boot security, including architecture-specific firmware paths.
• Default TPM 2.0: TPM 2.0 support is now enabled by default for Libvirt VMs, utilizing a software TPM emulator (swtpm) for hardware-based security features.
• Configurable Options: New command-line options, --firmware (to specify 'uefi', 'uefi-secure', or 'bios') and --disable-tpm, have been introduced for bcvk-libvirt-create and bcvk-libvirt-run to provide granular control over these features.
• XML Generation Logic: The internal domain XML generation logic has been significantly updated to correctly reflect the chosen firmware type and TPM configuration, ensuring proper Libvirt domain definitions.

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[gemini-code-assist]

Code Review

This pull request switches the default libvirt VM configuration to use UEFI firmware and enables TPM 2.0 support by default, which are great improvements for modern virtual machines. The changes introduce new command-line options to control these features and update the domain XML generation logic accordingly.

My review has identified a critical issue in the TPM XML generation that will prevent it from working. I've also suggested a refactoring to improve code maintainability, pointed out a portability issue with hardcoded firmware paths, and found a flaw in one of the new tests. Addressing these points will ensure the new features are robust and reliable.

[jmarrero]

lgtm