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Secure Boot and vTPM ("trusted launch")

Two options on VM create turn a plain UEFI VM into one that enforces signed boot and has a TPM:

OptionEffect
secure_boot: trueUEFI with Secure Boot enforced and the Microsoft and distribution keys enrolled. Needs firmware: "uefi".
vtpm: trueAn emulated TPM 2.0 (swtpm, CRB interface). Works with BIOS or UEFI.

Windows 11 needs both. Both default to off, so existing create calls behave as before.

curl -sk -X POST https://HOST:5092/api/v1/vms -H "Authorization: Bearer $TOKEN" \
  -H 'Content-Type: application/json' \
  -d '{"name":"win11","vcpus":4,"memory_mb":8192,"disk_gb":80,"firmware":"uefi",
       "secure_boot":true,"vtpm":true,"iso":"/isos/Win11.iso","os_variant":"win11"}'

How it works​

Secure Boot uses libvirt's firmware auto-selection (<os firmware='efi'> with the secure-boot and enrolled-keys features) plus System Management Mode (<smm state='on'/>), so libvirt chooses the signed OVMF build and a matching variable store from the host's firmware descriptors. The virt-install create path passes the equivalent --boot firmware=efi,..., --features smm=on and --tpm arguments. Machina checks the host first and refuses with a message that names the package to install:

  • Secure Boot: a firmware descriptor under /usr/share/qemu/firmware or /etc/qemu/firmware must advertise both features (edk2-ovmf on Fedora/RHEL, ovmf on Debian/Ubuntu).
  • TPM: swtpm (and swtpm-tools) must be installed.

Secure Boot VMs are created on the q35 machine type (the signed firmware requires it); the virt-install path asks for it explicitly.

An existing VM can still get a TPM later through the TPM attach call; it cannot be switched to Secure Boot in place.

Limits​

  • x86_64 q35 only. Guests that do not support Secure Boot will not boot unsigned media: leave secure_boot off for those.
  • The emulated TPM keeps its state on the host. It is not a hardware root of trust and does not provide remote attestation.
  • Confidential VMs (AMD SEV-SNP, Intel TDX) are not offered.
  • No web UI toggle yet; use the API or machinactl.
  • Run on a real host (2026-10-22): libvirt accepted and started a Secure Boot + vTPM VM. A Windows 11 install has not been run: see claims C60.