On 19.11.2012, at 23:51, David Gibson wrote: > On Mon, Nov 19, 2012 at 05:34:12PM +0100, Alexander Graf wrote: >> >> On 13.11.2012, at 03:47, David Gibson wrote: >> >>> From: Alexey Kardashevskiy <a...@ozlabs.ru> >>> >>> In future (with VFIO) we will have multiple PCI host bridges on >>> pseries. Each one needs a unique LIOBN (IOMMU id). At the moment we >>> derive these from the pci domain number, but the whole notion of >>> domain numbers on the qemu side is bogus and in any case they're not >>> actually uniquely allocated at this point. >>> >>> This patch, therefore uses a simple sequence counter to generate >>> unique LIOBNs for PCI host bridges. >>> >>> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> >>> Signed-off-by: David Gibson <da...@gibson.dropbear.id.au> >> >> I don't really like the idea of having a global variable just >> because our domain ID generation seems to not work as >> expected. Michael, any comments here? > > Well, the patch I sent which changed domain id generation was > ignored. In any case, as I said, the whole concept of domain numbers
Michael? > makes no sense on the qemu side, so I don't think increasing reliance > on them by using them here is a good idea. > > It would be conceptually nicer to derive the liobn from the buid, but > that would rely on the buid's being unique in the low 32-bits, which > is true in practice, but seems risky to rely on. Well, there has to be some uniqueness from the guest's POV already, no? Alex
