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RE: [Xen-devel] xensource (pci) device id's?

On Thu, 2007-02-01 at 12:02 -0800, Zulauf, John wrote:
> If we change all the PCI vendor ID's for the virtualized devices, how
> will the OS find the correct driver in standard HVM systems? 

Gerd is proposing to change the subvendor/subdevice ID's which is
different to the regular vendor/device ID.

The purpose of the subvendor/subdevice ID is to allow manufacturers to
take an existing PCI device chipset (with a given vendor/device ID burnt
in) and incorporate it into a card of their own. They can then use their
own subvendor/subdevice ID for this card and presumably have their own
driver match on these IDs rather than the more generic ones to offer
advanced functionality which is dependant on the board not the chipset

Linux at least matches primarily on the vendor/device IDs with
subvendor/subdevice set to match anything so we would be OK here. From
include/linux/pci.h here is the macro typically used by drivers:

        #define PCI_DEVICE(vend,dev) \
                .vendor = (vend), .device = (dev), \
                .subvendor = PCI_ANY_ID, .subdevice = PCI_ANY_ID

I'd be interested to know if this is true of other OSs such as Windows
and what matching procedure (if any) the PCI spec actually specifies.


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