Host capabilities

The interface reports what the application can observe about the host and gates machine creation and lifecycle operations on those results. A complete diagnostic still does not guarantee that a particular guest will boot or that the guest operating system is installed.

Readiness summary

The host panel summarizes its findings in three states:

• Diagnostics complete — no warning or error was reported.
• Setup incomplete — at least one warning was reported, such as missing QEMU or inaccessible KVM.
• Attention needed — at least one error was reported, or the application information could not be loaded.

These labels describe the diagnostics only. They do not confirm that a guest operating system is installed, that networking exists, or that a particular guest configuration will run successfully.

System

The System card reports the operating system, architecture, logical CPU count, total or available memory, and when the check ran. Memory status uses Available, Unavailable, or Error. A host that does not report usable memory produces an informational warning.

QEMU system emulator and qemu-img

Each tool card can show Available, Not found, Probe failed, or Unsupported. When a tool is found, the card shows the executable, version if it could be parsed, source, and path.

Discovery checks these locations in order:

1. Bundled resources under qemu/bin and qemu.
2. Directories on PATH.
3. Standard platform directories.

The version probe runs the executable directly with a version flag and a five-second timeout. It does not use a shell command string. A file that exists but cannot execute is reported as a probe failure, not as available.

KVM acceleration

On Linux, the KVM card reports the device path, whether the device is present, whether the kernel accepted the probe, and the reported API version. Its statuses are:

• Usable — /dev/kvm opened and KVM_GET_API_VERSION returned the expected API version (12).
• Not found — the device does not exist.
• No access — the device exists but opening it was denied.
• Probe failed — the device is not a character device, the ioctl failed, or the API version did not match.
• Not applicable — the platform is not Linux.

Application storage

The storage card reports the application data directory, mount point, free space, and total space. Statuses are Available, Unavailable, or Error. The application creates the data directory if needed. On Unix, directories are created with 0700 permissions and the configuration file with 0600.

Free space below 10 GiB produces a warning. That threshold is a diagnostic warning, not a guarantee that any particular VM will fit.

Common warnings

• qemu_missing, qemu_img_missing, kvm_missing — an optional component was not found.
• qemu_probe_failed, qemu_img_probe_failed, kvm_probe_failed — a component was found but could not be verified.
• kvm_inaccessible — the KVM device exists but the current user cannot open it.
• disk_space_low — less than 10 GiB is free on the application data filesystem.
• memory_unavailable, cpu_count_unavailable — the host did not report usable information.

What the diagnostics do not mean

The panel does not prove that a particular guest will boot, that the guest operating system is installed, or that KVM will be usable by every configuration. The current lifecycle uses these checks when creating and starting a machine; read Machine lifecycle for what happens after QEMU launches.