Il 08/11/2013 11:44, Peter Maydell ha scritto: > On 8 November 2013 08:05, Paolo Bonzini <pbonz...@redhat.com> wrote: >> Il 07/11/2013 22:51, Peter Maydell ha scritto: >>>>> 1. Not all architectures have the behavior: "Address space that is not >>>>> RAM(and friends) >>>>> is for sure PCI". Only x86 behaves like this (I think). >>> >>> More specifically, the x86 pc behaves like this. Other >>> x86 based systems could in theory behave differently >>> (not that we actually model any, I think). >> >> After Marcel's patch, we have changed behavior for at least all boards >> that pass get_system_memory() to pci_register_bus or pci_bus_new: >> >> * mips/gt64xxx_pci.c >> >> * pci-host/bonito.c >> >> * pci-host/ppce500.c >> >> * ppc/ppc4xx_pci.c >> >> * sh4/sh_pci.c > > Oh, right. Ideally those boards should not do that (I fixed > the versatile pci controller not to do that a while back) but > it's a long standing behaviour so it would be better had we > not broken it. > > I think it should in general be fixable by just having those > pci controllers create an empty memory region to pass in, > like versatile: > > memory_region_init(&s->pci_io_space, OBJECT(s), "pci_io", 1ULL << 32); > memory_region_init(&s->pci_mem_space, OBJECT(s), "pci_mem", 1ULL << 32); > > pci_bus_new_inplace(&s->pci_bus, sizeof(s->pci_bus), DEVICE(obj), "pci", > &s->pci_mem_space, &s->pci_io_space, > PCI_DEVFN(11, 0), TYPE_PCI_BUS); > > That doesn't affect where PCI DMA goes. It might also > require mapping an alias into that region at wherever > the pci hole is on those boards. > > Kind of awkward to do and test at this point in the release cycle though.
Yes, for now we should just revert the patch. BTW I tried optimizing MMIO dispatch and managed to save ~30 cycles so I don't think we should be afraid of increasing the depth of the radix tree. All stuff for 1.8 though. Paolo Paolo
