NAME
    xen-pci-device-reservations - Xen PCI device ID registry

Description
    PCI vendor ID 0x5853 has been reserved for use by Xen systems in order
    to advertise certain virtual hardware to guest virtual machines. The
    primary use of this is with device ID 0x0001 to advertise the Xen
    Platform PCI device - the presence of this virtual device enables a
    guest Operating System (subject to the availability of suitable drivers)
    to make use of paravirtualisation features such as disk and network
    devices etc.

    Some Xen vendors wish to provide alternative and/or additional guest
    drivers that can bind to virtual devices[1]. This may be done using the
    Xen PCI vendor ID of 0x5853 and Xen-vendor/device specific PCI device
    IDs. This file records reservations made within the device ID range in
    order to avoid multiple Xen vendors using conflicting IDs.

Guidelines
    1. A vendor may request a range of device IDs by submitting a patch to
    this file.
    2. Vendor allocations should be in the range 0xc000-0xfffe to reduce the
    possibility of clashes with community IDs assigned from the bottom up.
    3. The vendor is responsible for allocations within the range and should
    try to record specific device IDs in PCI ID databases such as
    http://pciids.sourceforge.net and http//www.pcidatabase.com

Reservations
            range     | vendor/product
        --------------+--------------------------------------------------------------
        0x0001        | (Xen Platform PCI device)
        0x0002        | Citrix XenServer (grandfathered allocation for XenServer 6.1)
        0xc000-0xc0ff | Citrix XenServer
        0xc100-0xc1ff | Citrix XenClient
        0xc200-0xc2ff | XCP-ng Project (https://xcp-ng.org)

Notes
    1.  Upstream QEMU provides a parameterized device called xen-pvdevice
        that can be used to host guest drivers. Execute:

            qemu-system-i386 -device xen-pvdevice,help

        for a list of all parameters. The following parameters are relevant
        to driver binding:

        vendor-id (default 0x5853)
            The PCI vendor ID and subsystem vendor ID of the device.

        device-id (must be specified)
            The PCI device ID and subsystem device ID of the device.

        revision (default 0x01)
            The PCI revision of the device

        Also the size parameter (default 0x400000) can be used to specify
        the size of the single MMIO BAR that the device exposes. This area
        may be used by drivers for mapping grant tables, etc.

        Note that the presence of the Xen Platform PCI device is generally a
        pre-requisite for an additional xen-pvdevice as it is the platform
        device that provides that IO ports necessary for unplugging emulated
        devices. See hvm-emulated-unplug.markdown for details of the IO
        ports and unplug protocol.

        libxl provides support for creation of a single additional
        xen-pvdevice. See the vendor_device parameter in xl.cfg(5).