PCIBACK(4) (xen)

PCIBACK(4) | Device Drivers Manual (xen) | PCIBACK(4)

# NAME

`pciback` —
Xen backend paravirtualized PCI pass-through driver

# SYNOPSIS

`pciback* at pci?`

# DESCRIPTION

The `pciback` driver is the backend part of the PCI pass-through functionality that can be used by the Xen dom0 to export pci(4) devices to a guest domain. To export a PCI device to a guest domain, the device has to be attached to `pciback` in the dom0.

When the guest domain is NetBSD, the device attached to the `pciback` driver will attach to a xpci(4) bus inside the guest domain.

# EXAMPLES

To attach a device to the `pciback` driver, follow these steps:

1. look for the device PCI ID, via pcictl(8).
2. edit boot.cfg(5) and add the PCI ID to the list of PCI IDs that you want to attach to `pciback`, in bus:device.function notation. The list is passed to dom0 module via the `pciback.hide` parameter:
   `pciback.hide=(bus:dev.fun)(bus:dev.func)(...)`
   See also boot(8).
3. reboot dom0.
4. add the PCI ID to the list of PCI devices in the domain configuration file:
   `pci = ['bus:dev.fun', '...']`
5. start the guest domain.

# SEE ALSO

pci(4), xpci(4), boot(8), pcictl(8)

# HISTORY

The `pciback` driver first appeared in NetBSD 5.1.

# AUTHORS

The `pciback` driver was written by Manuel Bouyer <bouyer@NetBSD.org>.

# CAVEATS

Currently, to attach a device to the `pciback` backend, this procedure has to be performed at boot(8) time. In the future, it will be possible to do it without requiring a dom0 reboot.

# SECURITY CONSIDERATIONS

As PCI passthrough offers the possibility for guest domains to send arbitrary PCI commands to a physical device, this has direct impact on the overall stability and security of the system. For example, in case of erroneous or malicious commands, the device could overwrite physical memory portions, via DMA.

January 8, 2011 | NetBSD 9.5