Messages in this thread | | | Date | Thu, 1 Jun 2023 20:05:25 +0200 | Subject | Re: [PATCH] KVM: SVM: vNMI pending bit is V_NMI_PENDING_MASK not V_NMI_BLOCKING_MASK | From | "Maciej S. Szmigiero" <> |
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On 1.06.2023 20:04, Sean Christopherson wrote: > On Thu, Jun 01, 2023, Maciej S. Szmigiero wrote: >> On 19.05.2023 17:51, Sean Christopherson wrote: >>> On Fri, May 19, 2023, Maciej S. Szmigiero wrote: >>>> From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> >>>> >>>> While testing Hyper-V enabled Windows Server 2019 guests on Zen4 hardware >>>> I noticed that with vCPU count large enough (> 16) they sometimes froze at >>>> boot. >>>> With vCPU count of 64 they never booted successfully - suggesting some kind >>>> of a race condition. >>>> >>>> Since adding "vnmi=0" module parameter made these guests boot successfully >>>> it was clear that the problem is most likely (v)NMI-related. >>>> >>>> Running kvm-unit-tests quickly showed failing NMI-related tests cases, like >>>> "multiple nmi" and "pending nmi" from apic-split, x2apic and xapic tests >>>> and the NMI parts of eventinj test. >>>> >>>> The issue was that once one NMI was being serviced no other NMI was allowed >>>> to be set pending (NMI limit = 0), which was traced to >>>> svm_is_vnmi_pending() wrongly testing for the "NMI blocked" flag rather >>>> than for the "NMI pending" flag. >>>> >>>> Fix this by testing for the right flag in svm_is_vnmi_pending(). >>>> Once this is done, the NMI-related kvm-unit-tests pass successfully and >>>> the Windows guest no longer freezes at boot. >>>> >>>> Fixes: fa4c027a7956 ("KVM: x86: Add support for SVM's Virtual NMI") >>>> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> >>> >>> Reviewed-by: Sean Christopherson <seanjc@google.com> >>> >> >> I can't see this in kvm/kvm.git trees or the kvm-x86 ones on GitHub - >> is this patch planned to be picked up for -rc5 soon? >> >> Technically, just knowing the final commit id would be sufficit for my >> purposes. > > If Paolo doesn't pick it up by tomorrow, I'll apply it and send a fixes pull > request for -rc5.
Thanks Sean.
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