Re: [Qemu-devel] [PATCH 2/4] pci: Add generic PCIe host bridge

[Alexander Graf]

On 12.01.15 21:08, Peter Maydell wrote:
> On 12 January 2015 at 17:38, Alexander Graf <address@hidden> wrote:
>> I'd prefer to keep things as easy as we humanly can for now. Then add
>> MSI. And if we then realize that we still need 4 rather than 1 shared
>> interrupt lines we can still change it :)
> 
> Except that that would be a breaking change, so I would prefer
> to think ahead where possible; at some point there will come
> a time when we really can't make breaking changes to this
> board any more...

Works for me, then we stay at a single interrupt line. The only reason
we have 4 in PCI is that back in the day you could have non-sharing PCI
devices that were essentially ISA ones.

If you actually care about interrupt latency and performance you will
want more than 4 IRQ lines, so you'll want MSI.


Alex