On Thu, Jul 03, 2014 at 01:27:05PM -0400, Bandan Das wrote: [...] ># modprobe kvm_intel ept=0 nested=1 enable_shadow_vmcs=0 > >The Host CPU - Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz >qemu cmd to run L1 - ># qemu-system-x86_64 -drive file=level1.img,if=virtio,id=disk0,format=raw,cache=none,werror=stop,rerror=stop,aio=threads -drive file=level2.img,if=virtio,id=disk1,format=raw,cache=none,werror=stop,rerror=stop,aio=threads -vnc :2 --enable-kvm -monitor stdio -m 4G -net nic,macaddr=00:23:32:45:89:10 -net tap,ifname=tap0,script=/etc/qemu-ifup,downscript=no -smp 4 -cpu Nehalem,+vmx -serial pty > >qemu cmd to run L2 - ># sudo qemu-system-x86_64 -hda VM/level2.img -vnc :0 --enable-kvm -monitor stdio -m 2G -smp 2 -cpu Nehalem -redir tcp:5555::22 > >Additionally, >L0 is FC19 with 3.16-rc3 >L1 and L2 are Ubuntu 14.04 with 3.13.0-24-generic > >Then start a kernel compilation inside L2 with "make -j3" > >There's no call trace on L0, both L0 and L1 are hung (or rather really slow) and >L1 serial spews out CPU softlock up errors. Enabling panic on softlockup on L1 will give >a trace with smp_call_function_many() I think the corresponding code in kernel/smp.c that >triggers this is > >WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled() > && !oops_in_progress && !early_boot_irqs_disabled); > >I know in most cases this is usually harmless, but in this specific case, >it seems it's stuck here forever. > >Sorry, I don't have a L1 call trace handy atm, I can post that if you are interested. > >Note that this can take as much as 30 to 40 minutes to appear but once it does, >you will know because both L1 and L2 will be stuck with the serial messages as I mentioned >before. From my side, let me try this on another system to rule out any machine specific >weirdness going on.. > Thanks for your pointing out. >Please let me know if you need any further information. > I just run kvm-unit-tests w/ vmx.flat and eventinj.flat. w/ vmx.flat and w/o my patch applied [...] Test suite : interrupt FAIL: direct interrupt while running guest PASS: intercepted interrupt while running guest FAIL: direct interrupt + hlt FAIL: intercepted interrupt + hlt FAIL: direct interrupt + activity state hlt FAIL: intercepted interrupt + activity state hlt PASS: running a guest with interrupt acknowledgement set SUMMARY: 69 tests, 6 failures w/ vmx.flat and w/ my patch applied [...] Test suite : interrupt PASS: direct interrupt while running guest PASS: intercepted interrupt while running guest PASS: direct interrupt + hlt FAIL: intercepted interrupt + hlt PASS: direct interrupt + activity state hlt PASS: intercepted interrupt + activity state hlt PASS: running a guest with interrupt acknowledgement set SUMMARY: 69 tests, 2 failures w/ eventinj.flat and w/o my patch applied SUMMARY: 13 tests, 0 failures w/ eventinj.flat and w/ my patch applied SUMMARY: 13 tests, 0 failures I'm not sure if the bug you mentioned has any relationship with "Fail: intercepted interrupt + hlt" which has already present before my patch. Regards, Wanpeng Li >Thanks >Bandan > >> Regards, >> Wanpeng Li >> >>>almost once in three times; it never happens if I run with ept=1, however, >>>I think that's only because the test completes sooner. But I can confirm >>>that I don't see it if I always set REQ_EVENT if nested_run_pending is set instead of >>>the approach this patch takes. >>>(Any debug hints help appreciated!) >>> >>>So, I am not sure if this is the right fix. Rather, I think the safer thing >>>to do is to have the interrupt pending check for injection into L1 at >>>the "same site" as the call to kvm_queue_interrupt() just like we had before >>>commit b6b8a1451fc40412c57d1. Is there any advantage to having all the >>>nested events checks together ? >>> >>>PS - Actually, a much easier fix (or rather hack) is to return 1 in >>>vmx_interrupt_allowed() (as I mentioned elsewhere) only if >>>!is_guest_mode(vcpu) That way, the pending interrupt interrupt >>>can be taken care of correctly during the next vmexit. >>> >>>Bandan >>> >>>> Jan >>>> >> [...] -- 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
