> -----Original Message----- > From: Jan Kiszka [mailto:jan.kiszka@xxxxxxxxxxx] > Sent: Wednesday, July 2, 2014 5:03 PM > To: Hu, Robert; Wanpeng Li; Paolo Bonzini; Gleb Natapov > Cc: kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > Subject: Re: [PATCH] KVM: nVMX: Fix IRQs inject to L2 which belong to L1 since > race > > On 2014-07-02 09:20, Hu, Robert wrote: > >> -----Original Message----- > >> From: Wanpeng Li [mailto:wanpeng.li@xxxxxxxxxxxxxxx] > >> Sent: Wednesday, July 2, 2014 2:54 PM > >> To: Paolo Bonzini; Jan Kiszka; Gleb Natapov > >> Cc: Hu, Robert; kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Wanpeng > Li > >> Subject: [PATCH] KVM: nVMX: Fix IRQs inject to L2 which belong to L1 since > race > >> > >> This patch fix bug https://bugzilla.kernel.org/show_bug.cgi?id=72381 > >> > >> If we didn't inject a still-pending event to L1 since nested_run_pending, > >> KVM_REQ_EVENT should be requested after the vmexit in order to inject the > >> event to L1. However, current log blindly request a KVM_REQ_EVENT even if > >> there is no still-pending event to L1 which blocked by nested_run_pending. > >> There is a race which lead to an interrupt will be injected to L2 which > >> belong to L1 if L0 send an interrupt to L1 during this window. > >> > >> VCPU0 another thread > >> > >> L1 intr not blocked on L2 first entry > >> vmx_vcpu_run req event > >> kvm check request req event > >> check_nested_events don't have any intr > >> not nested exit > >> intr occur (8254, lapic timer > >> etc) > >> inject_pending_event now have intr > >> inject interrupt > >> > >> This patch fix this race by introduced a l1_events_blocked field in nested_vmx > >> which indicates there is still-pending event which blocked by > >> nested_run_pending, > >> and smart request a KVM_REQ_EVENT if there is a still-pending event which > >> blocked > >> by nested_run_pending. > >> > >> Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx> > > Tested-by: Robert Hu<robert.hu@xxxxxxxxx> > > Do you happen to have a kvm-unit-test for this race? Or how did you > test? Just curious, and if there is a test, it would be good to > integrate it. I just apply the patch and test the reported scenario. > > Jan > > -- > Siemens AG, Corporate Technology, CT RTC ITP SES-DE > Corporate Competence Center Embedded Linux -- 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
