On Sun, 9 Sep 2012, Matthew Ogilvie wrote: > This bug manifested itself when the guest was Microport UNIX > System V/386 v2.1 (ca. 1987), because it would sometimes mask > off IRQ14 in the slave IMR after it had already been asserted. > The master would still try to deliver an interrupt even though > IRQ2 had dropped again, resulting in a spurious interupt > (IRQ15) and a panicked UNIX kernel. That is quite weird actually -- from my experience the spurious vector is never sent from a slave (quite understandably -- since the interrupt is gone and no other is pending, the master has no reason to select a slave to supply a vector and therefore supplies the spurious vector itself) and therefore a spurious IRQ7 is always issued regardless of whether the discarded request came from a slave or from the master. Is there a bug elsewhere then too? I would have expected a reasonable (and especially an old-school) x86 OS to be able to cope with spurious 8259A interrupts, but then obviously one would expect them on IRQ7 only. Maciej -- 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
