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

[Alex Williamson <alex.williamson@redhat.com>]

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

> > 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(-)