virt (QEMU)

Relevant source files


name = "virt"
memory = "1GB"
default_backend = "qemu"
backends = ["qemu"]

virt is the generic QEMU board covering three guest architectures, selected by VOLN_VP_ARCH (default aarch64). The per-architecture scripts under boards/virt/qemu/ each exec python3 backends/qemu/runner.py <arch> run "$@"; backends/qemu/adapters/run.sh selects one of them.

Machine configurations

All architectures share the base flags -accel tcg -display none -monitor none -serial stdio -no-reboot.

Arch	Machine flags	Inputs
`aarch64`	`-machine virt -m 1G -cpu cortex-a57 -kernel KERNEL`, raw disk as `virtio-blk-device` with `snapshot=on`, `-semihosting`	`AXIOMOS_KERNEL`, `AXIOMOS_DISK_IMAGE`
`x86_64`	`-m 4G -cpu max -smp 1 -vga none`, OVMF code as read-only pflash unit 0, OVMF vars as pflash unit 1 with `snapshot=on`, `-cdrom ISO`, raw disk as `virtio-blk-pci` with `snapshot=on`	`AXIOMOS_ISO`, `AXIOMOS_DISK_IMAGE`, `AXIOMOS_OVMF_CODE`, `AXIOMOS_OVMF_VARS`
`riscv64`	`-machine virt -bios default -kernel KERNEL`	`AXIOMOS_KERNEL`

Expected guest and markers

Arch	Expected image	`test` markers
`aarch64`	AArch64 ELF built for `virt,cloud-profile`, with a matching ext2 rootfs containing `/bin/init`	`=== axiomos eBPF init ===`
`x86_64`	axiomOS ISO + disk image + OVMF	`=== axiomos eBPF init ===`
`riscv64`	RISC-V demo ELF	both `axiomos RISC-V demo` and `Kernel booted via OpenSBI firmware` (demo boot, not userspace)

Status

As of the main evidence (2026-09-28 probe): x86_64 fails with BOOT_FATAL code=root-filesystem-invalid; AArch64 and RISC-V were not validated because no compatible prebuilt image was identified. See QEMU backend for runner behavior.