Re: [Qemu-devel] [PATCH 0/2] pci_bridge: Fixup/Cleanup bridge map_irq functions

[Michael S. Tsirkin]

On Sun, Mar 10, 2013 at 12:13:27PM -0600, Alex Williamson wrote:
> On Sun, 2013-03-10 at 18:16 +0200, Michael S. Tsirkin wrote:
> > On Thu, Mar 07, 2013 at 04:16:48PM -0700, Alex Williamson wrote:
> > > Rather than have everyone call pci_bridge_map_irq() themselves and
> > > come up with incorrect mapping functions let's use the default PCI
> > > defined swizzle function unless told otherwise.  Then we can also
> > > clean out the duplicate function in pci_bridge_dev.  Tested with an
> > > assigned device behind a PCIe switch behind a PCIe root port at
> > > addresses 0-3.  Note that Linux requires the pci=pcie_scan_all boot
> > > option to find devices behind PCIe ports if not addr=0.0.  Windows
> > > finds them but won't use them (code 10).
> > 
> > I'm guessing this only applies to downstream ports right?
> > The spec IIRC says that slot is ignored.
> > The real way is probably by making a device an endpoint
> > integrated into the switch, so it's behind the upstream port.
> 
> I think that's wrong.  The upstream device of an endpoint behind a
> switch should be the downstream port, followed by the upstream port.
> That's how we model it today and I think it's accurate.  Slot is
> undefined for an upstream port, but that's the PCIe slot, not the
> PCI_SLOT(devfn), aka "device", slot.  So I'm not sure how that's
> relevant here.
> 
> If there's something you want me to change please let me know, otherwise
> I'm at a loss how to incorporate changes based on this feedback.
> Thanks,
> 
> Alex

I applied the patch, no need to change anything.

I was only talking about testing this: while the spec says it's illegal,
you might be able to test this code by making an endpoint appear on the
switch's internal bus.  This isn't very useful except for testing
because it's out of spec.

> > > This replaces the ioh3420 & xio3130 upstream/downstream patches.
> > > Thanks,
> > > 
> > > Alex
> > > 
> > > ---
> > > 
> > > Alex Williamson (2):
> > >       pci_bridge: Use a default map_irq function
> > >       pci_bridge: Remove duplicate IRQ swizzle function
> > > 
> > > 
> > >  hw/pci/pci_bridge.c |    2 +-
> > >  hw/pci_bridge_dev.c |    9 ---------
> > >  2 files changed, 1 insertion(+), 10 deletions(-)
> 
>