AArch64 samples

The repository has three AArch64 single-machine samples, described together on this series page: host-only-aarch64, gem5-aarch64 and qemu-device-aarch64. All three use the vhost-arm-tcg host. The native execution architecture is AArch64 while the gem5 build target is still VEGA_X86. The Ubuntu/ROCm guest image shipped with the repository targets x86_64 only, so these samples cover host plumbing, plan rendering and the native ARM64 gem5 process, not a booting guest.

The three samples

Sample

Host

Devices

Memory pool

Notes

host-only-aarch64

vhost-arm-tcg (paused), 64 MiB, 1 vCPU

None

64 MiB

AArch64 host plumbing

gem5-aarch64

vhost-arm-tcg (paused), 512 MiB, 1 vCPU

1 × mi300x-aarch64, 1 GiB VRAM, 4 CU

1.5 GiB

Native ARM64 gem5 build

qemu-device-aarch64

vhost-arm-tcg (paused), 64 MiB, 1 vCPU

1 × qemu-edu-aarch64 (id edu)

64 MiB

Depends on AArch64 build artifacts

host-only-aarch64 machine

resources/machines/host-only-aarch64.yaml imports from vhosts/qemu.yaml and vhosts/vhost-arm-tcg.yaml and declares a single paused AArch64 host for AArch64 session plumbing.

just run-cli validate resources/machines/host-only-aarch64.yaml
just run-topology resources/machines/host-only-aarch64.yaml --dry-run
just run-topology-dev resources/machines/host-only-aarch64.yaml --run-for 1

  • Machine count: one (m0); one vHost and no devices.

  • The 64 MiB pool; the host binary qemu-system-aarch64 is looked up in PATH.

gem5-aarch64 machine

resources/machines/gem5-aarch64.yaml combines a paused ARM64 host with one native ARM64 gem5 MI300X process:

  • The host overrides runtime.binary to build/qemu/qemu-system-aarch64 and sets memory to 512 MiB.

  • The device uses the mi300x-aarch64 template: binary build/gem5/aarch64/VEGA_X86/gem5.opt, VRAM overridden to 1 GiB, and num_compute_units set to 4.

  • The explicit device id is gpu0, its region is gpu0.vram at 512 MiB, and the pool is 1.5 GiB.

  • The vHost has no image or kernel because no AArch64 guest image is shipped.

just run-cli validate resources/machines/gem5-aarch64.yaml
just run-topology resources/machines/gem5-aarch64.yaml --dry-run

qemu-device-aarch64 machine

resources/machines/qemu-device-aarch64.yaml mirrors the x86_64 qemu-device machine: a paused AArch64 host connects to a QEMU edu device over vfio-user.

  • The host overrides runtime.binary to build/qemu/qemu-system-aarch64.

  • The device uses the qemu-edu-aarch64 template with the explicit id edu; it has no private memory region.

  • The pool is 64 MiB; both the x86_64 and AArch64 host and device binaries need a QEMU built with vfio-user support.

just run-cli validate resources/machines/qemu-device-aarch64.yaml
just run-topology resources/machines/qemu-device-aarch64.yaml --dry-run

Shared constraints

  • just build-qemu builds for the host architecture (COSIM_HOST_ARCH, defaulting to the current architecture); the AArch64 samples need build/qemu/qemu-system-aarch64 and the gem5 binary built on an AArch64 host.

  • just build-gem5 writes its output under build/gem5/<host_arch>/VEGA_X86; the gem5 build target is always VEGA_X86 and only the native execution architecture differs.

  • There is no AArch64 guest image: these vHosts cannot boot a guest OS.

  • The vhost-arm template (KVM, virt,gic-version=3) exists, but the repository samples reference only vhost-arm-tcg.

  • Architecture-dependent tests select vhost-arm-tcg on AArch64; every sample is loaded by the render test.