[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH QEMU-XEN] xen/pt: Start with emulated PCI_COMMAND set to zero.
On Thu, Jun 11, 2015 at 01:19:34PM +0200, Sander Eikelenboom wrote: > > Thursday, June 11, 2015, 9:47:47 AM, you wrote: > > >>>> On 10.06.15 at 22:53, <konrad@xxxxxxxxxx> wrote: > >> --- a/hw/xen/xen_pt.c > >> +++ b/hw/xen/xen_pt.c > >> @@ -785,7 +785,9 @@ out: > >> xen_host_pci_set_word(&s->real_device, PCI_COMMAND, > >> pci_get_word(d->config + PCI_COMMAND) | > >> cmd); > >> } > >> - > >> + /* Until the guest enables the device use d->config values which will > >> + * inhibit pci_bar_address & pci_update_mappings from triggering > >> updates.*/ > >> + pci_set_word(d->config + PCI_COMMAND, 0); > >> memory_listener_register(&s->memory_listener, &address_space_memory); > >> memory_listener_register(&s->io_listener, &address_space_io); > >> XEN_PT_LOG(d, > > > Well, I can see this as something to be tried out as an experiment, > > but it looks like you mean this to be a proper submission for > > inclusion upstream? Or maybe not, considering that qemu-devel I needed to make sure that Sander's test-case is indeed fixed with this. And it looks like it is which makes further development of this much simpler since I can reproduce this. > > wasn't even Cc-ed? In any case - what we need here is a general > > solution to at least the initialization part of the problem, i.e. all > > fields we emulate some or all bits for need to have d->config[] > > updated accordingly (i.e. you need to merge d->config[] and > > XenPTReg's data field based on the respective XenPTRegInfo's > > emu_mask, but perhaps simply copying the data field to > d->>config[] would have the same effect; if it doesn't, we have > > yet another problem). For the command register this for example > > means that it is in no way guaranteed that it would end up being > > zero; its emu_mask however guarantees that the memory and I/O > > decode bits would start out as zero (which is what you're after). Right, I hope :-) > > Just tested this patch together with a dom0 kernel which has the dropped > kernel patch from Konrad: > 22d8a8938407cb1342af763e937fdf9ee8daf24a xen/pciback: Don't disable > PCI_COMMAND on PCI device reset. > > And this patch does help to prevent the issue from happening. Yeeey! > > -- > Sander > > > Jan > > > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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