From: Maxim Levitsky <mlevitsk@redhat.com>
To: kvm@vger.kernel.org
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
Joerg Roedel <joro@8bytes.org>, Ingo Molnar <mingo@redhat.com>,
x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
"H. Peter Anvin" <hpa@zytor.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Borislav Petkov <bp@alien8.de>, Jim Mattson <jmattson@google.com>,
Wanpeng Li <wanpengli@tencent.com>,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Maxim Levitsky <mlevitsk@redhat.com>
Subject: [PATCH 1/1] KVM: x86: ignore SIPIs that are received while not in wait-for-sipi state
Date: Thu, 3 Dec 2020 16:33:19 +0200 [thread overview]
Message-ID: <20201203143319.159394-2-mlevitsk@redhat.com> (raw)
In-Reply-To: <20201203143319.159394-1-mlevitsk@redhat.com>
In the commit 1c96dcceaeb3
("KVM: x86: fix apic_accept_events vs check_nested_events"),
we accidently started latching SIPIs that are received while the cpu is not
waiting for them.
This causes vCPUs to never enter a halted state.
Fixes: 1c96dcceaeb3 ("KVM: x86: fix apic_accept_events vs check_nested_events")
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
arch/x86/kvm/lapic.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index e3ee597ff5404..6a87623aa578e 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2892,14 +2892,15 @@ void kvm_apic_accept_events(struct kvm_vcpu *vcpu)
else
vcpu->arch.mp_state = KVM_MP_STATE_INIT_RECEIVED;
}
- if (test_bit(KVM_APIC_SIPI, &pe) &&
- vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) {
+ if (test_bit(KVM_APIC_SIPI, &pe)) {
clear_bit(KVM_APIC_SIPI, &apic->pending_events);
- /* evaluate pending_events before reading the vector */
- smp_rmb();
- sipi_vector = apic->sipi_vector;
- kvm_vcpu_deliver_sipi_vector(vcpu, sipi_vector);
- vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
+ if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) {
+ /* evaluate pending_events before reading the vector */
+ smp_rmb();
+ sipi_vector = apic->sipi_vector;
+ kvm_vcpu_deliver_sipi_vector(vcpu, sipi_vector);
+ vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
+ }
}
}
--
2.26.2
next prev parent reply other threads:[~2020-12-03 14:51 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-03 14:33 [PATCH 0/1] Fix for a recent regression in kvm/queue (guest using 100% cpu time) Maxim Levitsky
2020-12-03 14:33 ` Maxim Levitsky [this message]
2020-12-03 17:36 ` [PATCH 1/1] KVM: x86: ignore SIPIs that are received while not in wait-for-sipi state Paolo Bonzini
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