On Tue, Oct 13, 2015 at 09:16:34AM +0100, Peter Maydell wrote: > On 13 October 2015 at 07:31, Alexander Gordeev <agord...@redhat.com> wrote: > > On Mon, Oct 12, 2015 at 10:03:03PM +0100, Peter Maydell wrote: > >> On 12 October 2015 at 21:55, Alexander Gordeev <agord...@redhat.com> wrote: > >> > Currently PCI IO address 0 is not allowed even though > >> > the IO space starts from 0. As result, PCI IO is not > >> > possible to use at all. > >> > >> I don't see any reason for us not to allow 0 IO addresses, > >> but I'm not sure how your your conclusion follows. It > >> should be entirely possible to map PCI IO to some other > >> address than zero in the IO window, which is what I would > >> have expected the guest to do. > > > > You are right - my changelog is incorrect. The rest of IO > > space should be alright. > > > > However, as 0 IO address is exposed via "ranges" to the guest, > > it must be usable - isn't it? So it either should be allowed > > or the range should be different. > > Depends on your point of view. If you take the Linus Torvalds > view that 0 is always an invalid PCI address, then you'll > never try to use it anyway. > > In any case, setting pci_allow_0_address is the right thing, > so we can just change the commit message in this patch.
I will post v2 with an updated changelog then. > Incidentally, why is this a property on the machine > and not on the PCI controller device? I am CC-ing Laurent Vivier who introduced the flag. But IMO it *is* a machine property, not PCI controller's one, unless I am missing something. Thanks! > thanks > -- PMM -- Regards, Alexander Gordeev agord...@redhat.com
