> For the complete documentation index, see [llms.txt](https://docs.layeronecloud.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.layeronecloud.com/pve-microvm/limitations.md).

# Limitations

Source project: `pve-microvm` (migrated from `docs/limitations.md`). Run commands from the code checkout and directory specified below, not from this documentation repository.

## No display <a href="#no-display" id="no-display"></a>

No VGA, QXL, or virtio-gpu. No VNC/SPICE. Serial console only via xterm.js (PVE web UI auto-selects xterm.js for microvm, or use `qm terminal`).

## No PCI passthrough <a href="#no-pci-passthrough" id="no-pci-passthrough"></a>

The microvm machine type uses a minimal PCIe bus (`pcie=on`) for virtio device transport. PCI passthrough of host devices (GPUs, NICs, etc.) is not supported.

## No USB <a href="#no-usb" id="no-usb"></a>

No USB controllers. No USB passthrough.

## No UEFI / Secure Boot <a href="#no-uefi--secure-boot" id="no-uefi--secure-boot"></a>

Direct kernel boot only. No firmware, no EFI variables.

## Kernel required <a href="#kernel-required" id="kernel-required"></a>

Unlike standard VMs, microvm always needs `-kernel` in `args`. The kernel and initrd must be on the Proxmox host filesystem (installed to `/usr/share/pve-microvm/` by the package).

## No CD-ROM / ISO boot <a href="#no-cd-rom--iso-boot" id="no-cd-rom--iso-boot"></a>

Cannot boot from ISO. Use `pve-microvm-template` to build from OCI images, or import ext4/raw disk images directly with `qm importdisk`.

## No live migration <a href="#no-live-migration" id="no-live-migration"></a>

Live migration (`qm migrate --online`) is not supported for the microvm machine type. Offline migration works — HA relocate performs a stop→migrate→start cycle automatically (tested z83ii↔borg, \~2 seconds).

## No ACPI power button <a href="#no-acpi-power-button" id="no-acpi-power-button"></a>

No ACPI power button. `qm shutdown` requires the guest agent. Use `qm stop` for force shutdown.

## Limited NICs <a href="#limited-nics" id="limited-nics"></a>

Current implementation supports up to 6 network interfaces per guest. Can be increased in `MicroVM.pm`.

## Serial buffer <a href="#serial-buffer" id="serial-buffer"></a>

QEMU's serial chardev socket does not buffer output when no client is connected. Boot messages may be lost. Connect via `qm terminal` after boot to get an interactive shell.

## Kernel config <a href="#kernel-config" id="kernel-config"></a>

Uses `x86_64_defconfig` with an overlay for virtio, vsock, virtiofs, and Docker support (BPF, netfilter, overlay-fs, bridge). The Firecracker 6.1 kernel config is NOT compatible — it has broken virtio device ID tables on kernel 6.12+. Always use the shipped kernel.

## 9Front / Plan 9 (experimental) <a href="#id-9front--plan-9-experimental" id="id-9front--plan-9-experimental"></a>

Uses q35 (not microvm machine type) since Plan 9 boots from disk via BIOS. Serial console requires `console=0` at boot or editing `plan9.ini`.

## OSv (experimental) <a href="#osv-experimental" id="osv-experimental"></a>

Uses q35 with `-kernel` boot. The loader image needs a separate application image (built with `capstan` or `ops`) attached as a disk.


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