[Qemu-devel] Re: Hitting 29 NIC limit

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

On Thu, Nov 18, 2010 at 12:09:18PM +0900, Isaku Yamahata wrote:
> Right now, qemu is internally ready to handle pci-to-pci bridge emulators
> and it's quite easy to add a new simple p2p bridge emulator.
> Just a single function to initialize vid/did and a single PCIDevinceInfo.
> 
> But it's difficult to use multi pci buses at the moment
> because other part isn't ready. It's only for developers
> who are interested in this area.
> 
> BTW, how many pci buses/slots/functions do you want at most?
> 
> 
> What we have in the upstream repository is
> - various fixes for p2p bridge support
> - the library for p2p bridge support
> - pcie root/upstream/downstream port emulators which is p2p bridges
>   ioh3420/xio3130_upstream/xio3130_downstream
> 
> What is missing for multiple pci buses is
> - a new PC machine description which has multiple pci buses
>   My Q35 chipset patch will provide this.

IMHO, what we really need is a way to specify bridges
through qdev. Not a machine with a hard-coded buses.
The firmware paths used by Gleb's code might supply
a good syntax to specify topology.

> - a simple P2P bridge emulator for pc architecture
> - seabios support
>   - DSDT for a new machine which has multi pci buses(IRQ routing)
>   - pv pci bus numbering

Interesting. What's the motivation for this?

>     this isn't a must, I suppose
>   I have those patches locally.
> 
> thanks,
> 
> On Wed, Nov 17, 2010 at 12:58:43PM +0200, Michael S. Tsirkin wrote:
> > On Tue, Nov 16, 2010 at 11:20:52AM -0800, Anjali Kulkarni wrote:
> > > Hi,
> > > 
> > > Can you elaborate what you mean by bridge support? I would really like to go
> > > to 256 interfaces.
> > > 
> > > Anjali
> > 
> > Isaku Yamahata wrote most of it, I'll let him comment.
> > 
> > -- 
> > MST
> > 
> 
> -- 
> yamahata