On 11/22/2017 11:54 AM, Christian König wrote: > Am 22.11.2017 um 17:24 schrieb Boris Ostrovsky: >> On 11/22/2017 05:09 AM, Christian König wrote: >>> Am 21.11.2017 um 23:26 schrieb Boris Ostrovsky: >>>> On 11/21/2017 08:34 AM, Christian König wrote: >>>>> Hi Boris, >>>>> >>>>> attached are two patches. >>>>> >>>>> The first one is a trivial fix for the infinite loop issue, it now >>>>> correctly aborts the fixup when it can't find address space for the >>>>> root window. >>>>> >>>>> The second is a workaround for your board. It simply checks if there >>>>> is exactly one Processor Function to apply this fix on. >>>>> >>>>> Both are based on linus current master branch. Please test if they >>>>> fix >>>>> your issue. >>>> Yes, they do fix it but that's because the feature is disabled. >>>> >>>> Do you know what the actual problem was (on Xen)? >>> I still haven't understood what you actually did with Xen. >>> >>> When you used PCI pass through with those devices then you have made a >>> major configuration error. >>> >>> When the problem happened on dom0 then the explanation is most likely >>> that some PCI device ended up in the configured space, but the routing >>> was only setup correctly on one CPU socket. >> The problem is that dom0 can be (and was in my case() booted with less >> than full physical memory and so the "rest" of the host memory is not >> necessarily reflected in iomem. Your patch then tried to configure that >> memory for MMIO and the system hang. >> >> And so my guess is that this patch will break dom0 on a single-socket >> system as well. > > Oh, thanks! > > I've thought about that possibility before, but wasn't able to find a > system which actually does that. > > May I ask why the rest of the memory isn't reported to the OS? That memory doesn't belong to the OS (dom0), it is owned by the hypervisor. > > Sounds like I can't trust Linux resource management and probably need > to read the DRAM config to figure things out after all. My question is whether what you are trying to do should ever be done for a guest at all (any guest, not necessarily Xen). -boris
