Hardware

The Hardware tab controls the virtual hardware presented to a VM: CPU topology and pinning, memory, remote console access, PCI passthrough, and TPM emulation.

Caution

Shut the VM down before making hardware changes. Sylve disables the edit action while the VM is running and the backend also rejects hardware changes unless the VM is fully stopped.

Hardware overview

Select an entry in the table, then choose Edit to open its configuration. The table is also a quick view of the VM’s current topology and enabled capabilities.

Entry	What it controls
vCPUs	CPU topology and optional pinning of guest vCPUs to host logical CPUs.
RAM	The memory allocated to the VM.
VNC	The graphical console listener, its bind address, port, resolution, and password.
Serial Console	Whether Sylve presents a serial device to the guest.
PCI Devices	Prepared PCI devices passed directly through to the VM.
TPM Emulation	A virtual Trusted Platform Module for guests that require TPM features.

CPU and memory

CPU topology and pinning

Set the number of sockets, cores, and threads per core. Their product is the total number of vCPUs presented to the guest. For example, 1 × 4 × 2 presents eight vCPUs.

Do not enter the total vCPU count twice

For a 16-vCPU guest with one thread per core, configure 1 × 16 × 1: one socket, 16 cores, and one thread per core. Setting both Cores and Threads to 16 creates 1 × 16 × 16, or 256 vCPUs. Use more than one thread per core only when you deliberately want that topology exposed to the guest.

Optionally choose host logical CPUs in CPU Selector to pin individual guest vCPUs. Pinning is useful for workloads that need predictable CPU placement. Sylve validates the selected topology and rejects duplicate pins, pins outside the host CPU range, pin counts larger than the VM’s vCPU count, and pins already reserved by another VM.

Configure the topology

Pin guest vCPUs

Memory

RAM is configured in MiB. Sylve requires at least 128 MiB and the UI prevents an allocation that would leave less than 1 GiB available to the host. Treat that as a minimum guardrail, not a sizing recommendation. FreeBSD, ZFS, and other services need memory too, especially on nodes with active ARC caching or several running VMs.

Console hardware

VNC

Enable VNC to give the VM a graphical console. Choose an IPv4 or IPv6 Bind IP, a port from 5900 to 65535, a resolution, and optionally a password. Sylve checks the selected port against other VMs and against host TCP listeners before saving it.

Wait for VNC makes the guest wait for a VNC client connection before continuing. This is useful when you need to observe early boot or an installer.

The VNC value in the Hardware table is clickable. Select it to copy a VNC connection URI for an external client. If you configured a password, the copied URI includes it, so handle the clipboard contents as sensitive.

For using the in-browser graphical or serial console, see Console.

Serial console

Enable Serial Console to add a serial device to the VM. The guest operating system must also be configured to send a login prompt and kernel output to that device. Once the guest is ready, open the serial console from the Console tab.

PCI passthrough

PCI passthrough gives a VM direct access to a prepared physical device, such as a GPU, NIC, storage controller, or USB controller. First prepare the device under PCI Passthrough, restart the node as recommended there, then select it here.

The picker identifies devices that are already assigned to another VM. A device assigned to a stopped VM can be reassigned after you remove it from that VM. A device in use by a running VM cannot be used elsewhere, and Sylve prevents the conflicting VM from starting.

TPM emulation

Enable TPM Emulation when the guest requires a TPM, for example for an operating-system feature that stores credentials or encryption state in TPM-backed storage.

Caution

Do not disable TPM emulation casually after the guest has started using it. A guest that has enrolled keys, encryption protectors, or boot state with the virtual TPM can fail to boot or require recovery after it is removed.