On Sun, Dec 20, 2015 at 09:49:54AM +0000, Gonglei (Arei) wrote: > > From: Kevin O'Connor [mailto:kevin@xxxxxxxxxxxx] > > Sent: Saturday, December 19, 2015 11:12 PM > > On Sat, Dec 19, 2015 at 12:03:15PM +0000, Gonglei (Arei) wrote: > > > Maybe the root cause is not NMI but INTR, so yield() can open hardware > > interrupt, > > > And then execute interrupt handler, but the interrupt handler make the > > SeaBIOS > > > stack broken, so that the BSP can't execute the instruction and occur > > exception, > > > VM_EXIT to Kmod, which is an infinite loop. But I don't have any proofs except > > > the surface phenomenon. > > > > I can't see any reason why allowing interrupts at this location would > > be a problem. > > > Does it have any relationship with *extra stack* of SeaBIOS? None that I can see. Also, the kvm trace seems to show the code trying to execute at rip=0x03 - that will crash long before the extra stack is used. > > > Kevin, can we drop yield() in smp_setup() ? > > > > It's possible to eliminate this instance of yield, but I think it > > would just push the crash to the next time interrupts are enabled. > > > Perhaps. I'm not sure. > > > > Is it really useful and allowable for SeaBIOS? Maybe for other components? > > > I'm not sure. Because we found that when SeaBIOS is booting, if we inject a > > > NMI by QMP, the guest will *stuck*. And the kvm tracing log is the same with > > > the current problem. > > > > If you apply the patches you had to prevent that NMI crash problem, > > does it also prevent the above crash? > > > Yes, but we cannot prevent the NMI injection (though I'll submit some patches to > forbid users' NMI injection after NMI_EN disabled by RTC bit7 of port 0x70). > -Kevin -- 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
