>>>> Hi, all >>>> >>>> I use a qemu-1.4.1/qemu-2.0.0 to run win7 guest, and encounter e1000 NIC interrupt storm, >>>> because "if (!ent->fields.mask && (ioapic->irr & (1 << i)))" is always true in __kvm_ioapic_update_eoi(). >>>> >>>> Any ideas? >>> We meet this several times: search the autoneg patches for an example of >>> workaround for this in qemu, and patch kvm: ioapic: conditionally delay >>> irq delivery during eoi broadcast for an workaround in kvm (rejected). >>> >> Thanks, Jason, >> I searched "e1000 autoneg" in gmane.comp.emulators.qemu, and found below patches, >> http://thread.gmane.org/gmane.comp.emulators.qemu/143001/focus=143007 > >This series is the first try to fix the guest hang during guest >hibernation or driver enable/disable. >> http://thread.gmane.org/gmane.comp.emulators.qemu/284105/focus=284765 >> http://thread.gmane.org/gmane.comp.emulators.qemu/186159/focus=187351 > >Those are follow-up that tries to fix the bugs introduced by the autoneg >hack. >> which one tries to fix this problem, or all of them? > >As you can see, those kinds of hacking may not as good as we expect >since we don't know exactly how e1000 works. Only the register function >description from Intel's manual may not be sufficient. And you can >search e1000 in the archives and you can find some behaviour of e1000 >registers were not fictionalized like what spec said. It was really >suggested to use virtio-net instead of e1000 in guest. We support both, virtio-net is the recommended option, with regard to some guest (e.g., windows server 2000), virtio-net is not supported, e1000 is the last option. >> >>> That was probably caused by something wrong in e1000 emulation which >>> causes interrupt to be injected into windows guest before its interrupt >>> handler is registered. And Windows guest does not have a mechanism to >>> detect and disable irq in such condition. >>> >> Sorry, I don't understand, >> I think one interrupt should not been enabled before its handler is successfully registered, >> is it possible that e1000 emulation inject the interrupt before the interrupt is succesfully enabled? >> >> Thanks, >> Zhang Haoyu >> >>> e1000 emulation is far from stable and complete (e.g run e1000 ethtool >>> selftest in linux guest may see lots of errors). It's complicate and >>> subtle (even has undocumented registers and behaviour). You should >>> better consider to use virtio which are more stable and fast in a kvm >>> guest (unless some intel guys are involved to improve e1000 emulation). >>> >>> Thanks >>>> Thanks, >>>> Zhang Haoyu -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
