OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx> writes: >>> That is correct, kvm doesn't connect the master 8259 output to the >>> IOAPIC. Instead the 8259 is connected to LINT0 (which is configured for >>> ExtInt when the IOAPIC is disabled, or for NMI which the NMI watchdog is >>> enabled). >>> >>> However, now I can't see how it would work. auto EOI works on the INTA >>> cycle, which would only occur if LINT0 is configured for ExtInt. If it >>> is configured for NMI, I don't think it would issue the INTA cycle. So >>> the NMI watchdog not working is actually correct for our hardware >>> configuration! >>> >>> But I may be misunderstanding something here. >> >> I see. If the physical machine was configured as above, I guess (not >> pretty sure, I don't have this configuration machine), IOAPIC test >> (check_timer() in io_apic.c) should fail, and IOAPIC wouldn't have any >> effect. And I think MADT should tell mp_ExtINT. >> >> Yes, I also guess the above configuration wouldn't work NMI watchdog of >> IOAPIC mode, and linux will report as NMI watchdog can't work in >> check_timer(). > > Hm.., if smp was enabled, what configuration model is used by kvm? I > think this configuration model can't work on smp. As far as I can see, kvm is not configured (from MADT and some of behaviors) like you said. So, I think there are some solutions, a) current behavior is right (I don't know why it's right though), b) fix the behavior of IO-APIC and MADT like you said, then linux can detect it, c) change the model to like mpspec figure 5-2, d) other. My suggestion is c) if there is no good d). Because current behavior looks like almost c), and non-legacy chipsets are using c) model as far as I know. Thanks. -- OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx> -- 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
