Re: [Qemu-devel] [PATCH 0/2] add pci-serial device.

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Sep 27, 2012 at 07:53:47AM +0200, Gerd Hoffmann wrote:
>   Hi,
> 
> > Understood, but I'd really prefer a file in docs/.  We should be
> > rigorous about having formal specs for all of our paravirtual devices.
> > The code shouldn't be the spec.
> 
> Well, pci-serial and pci-bridge are *not* paravirtual devices.
> 
> They follow a specification describing the programming interface, and
> likewise does real hardware.  Same is true for all usb host controllers
> and ahci btw.  I can certainly place a text file for pci-serial in
> docs/spec/, but there isn't much qemu-specific to specify ...
> 
> Guests have generic drivers which just match the PCI class and
> programming interface fields in the pci config space and don't care
> (much) what the pci id is.  The pci id is used to print the name of the
> hardware, apply quirks, handle vendor-specific extensions, and in case
> of pci-serial windows also uses it to figure whenever the device is just
> a serial port or a modem (behind a 16550).
> 
> Whenever we'll pick the pci ids of existing hardware or assign a unique
> one is a matter of taste.  Picking unique IDs from Red Hat vendor space
> doesn't make the devices paravirtual.  usb controllers and ahci got IDs
> matching the ones of the intel chipsets (piix, q35) emulated by qemu,
> which makes sense in that case.
> 
> For pci-serial windows needs a "driver" (which is just a inf file, the
> driver itself is shipped by windows).  So in that case it is easier to
> go with our own ids I think, as we can simply ship a inf file then.
> When picking the IDs of other cards, existing as real hardware, users
> would have to hunt down the (non-redistributable) driver package for the
> real hardware to get it going in windows.
> 
> cheers,
>   Gerd

Any way to bypass the need to distribute the inf?

-- 
MST