linux-kernel - [PATCH 0/1] Fix for a recent regression in kvm/queue (guest using 100% cpu time)

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Message-Id: <20201203143319.159394-1-mlevitsk@redhat.com>
Date:   Thu,  3 Dec 2020 16:33:18 +0200
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     kvm@...r.kernel.org
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Joerg Roedel <joro@...tes.org>, Ingo Molnar <mingo@...hat.com>,
        x86@...nel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
        "H. Peter Anvin" <hpa@...or.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Borislav Petkov <bp@...en8.de>,
        Jim Mattson <jmattson@...gle.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
        Maxim Levitsky <mlevitsk@...hat.com>
Subject: [PATCH 0/1] Fix for a recent regression in kvm/queue (guest using
 100% cpu time)

I did a quick bisect yesterday after noticing that my VMs started
to take 100% cpu time.

Looks like we don't ignore SIPIs that are received while the CPU isn't
waiting for them, and that makes KVM think that CPU always has
pending events which makes it never enter an idle state.

Best regards,
	Maxim Levitsky

Maxim Levitsky (1):
  KVM: x86: ignore SIPIs that are received while not in wait-for-sipi
    state

 arch/x86/kvm/lapic.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

-- 
2.26.2