On Thu, Aug 28, 2014 at 10:33:02PM +0100, Peter Maydell wrote: > On 28 August 2014 22:21, Michael Roth <mdr...@linux.vnet.ibm.com> wrote: > > But I guess there's still a separate issue, where there's a high liklihood > > that > > a 0 address would conflict with some hard-wired IO address? Wouldn't this > > be a > > guest bug though?
Real hardware behaves in a specific way. the problem is we don't always emulate it properly, and PCI has some work arounds for that. > Even if it's a guest bug, we should act like the hardware does > if the guest does this. If that differs between PCI controllers > then we need a flag so the host controller model can select > the required behaviour. (The versatile PB PCI controller we > model does have "address 0 is valid", and we'd need to have > this working if we implemented DMA accesses properly.) > > -- PMM Exactly. Actually, I forgot that I might have already fixed it for PC: 83d08f2673504a299194dcac1657a13754b5932a pc: map PCI address space as catchall region for not mapped addresses But need to go back and re-check other systems. -- MST