Re: [Qemu-devel] [RFC PATCH 1/3] tests: add libpci qtest library

[Anthony Liguori]

On 04/16/2012 04:14 AM, Stefan Hajnoczi wrote:
> On Sat, Apr 14, 2012 at 12:32:00PM +0000, Blue Swirl wrote:
> > On Fri, Apr 13, 2012 at 14:27, Stefan Hajnoczi
> > <address@hidden>  wrote:
> > > This patch adds a common PCI bus driver library which works for
> > > i386/x86-64 targets.  Tests can use the library to probe for PCI
> > > devices, map BARs, and access configuration space.
> >
> > I guess we have almost identical code in SeaBIOS, OpenBIOS, various OS
> > and maybe userland PCI tools. Would it be possible to reduce NIH
> > somewhere?
>
> Probably not given how small these functions are and how they use glib
> assert calls because they are part of tests.
>
> > > +void pci_config_writel(PciDevice *dev, unsigned int offset, uint32_t l)
> > > +{
> > > +    pci_config_setup(dev, offset);
> > > +    outl(PCI_CONFIG_DATA, l);
> > > +}
> >
> > All code above is specific to i440fx or similar PCI bridges, other
> > bridges may use different config space access methods. If we want to
> > share the rest for example with Sparc64 or PPC, the above would need
> > to be changed. How about splitting the above to a separate file? It
> > could be done later too.
>
> Yes, it's only i440fx for now.  I think it makes sense to move it later
> since we have no non-x86 qtests yet.

Note that this isn't i440fx specific at all.  cf8 is the standard port for PCI 
on the PC.

I think what we'll want to eventually do is make a pci_config_read/pci_write() 
set of function pointers that can be overloaded.

But definitely don't name it libqtest-i440fx.  At least call it libqtest-pc.c

Regards,

Anthony Liguori

> > > +
> > > +/* Initialize a PciDevice if a device is present on the bus */
> >
> > The comment talks about initalizing instead of only probing which is
> > actually what the code does, please fix.
>
> Sorry this comment is unclear.  I meant initializing the "PciDevice"
> struct, not the physical PCI device.  Will change.
>
> Stefan