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From: "Radim Krčmář" <rkrcmar@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
	Yuki Shibuya <shibuya.yk@ncos.nec.co.jp>
Subject: [PATCH] KVM: x86: zero apic_arb_prio on reset
Date: Fri, 30 Oct 2015 15:48:20 +0100	[thread overview]
Message-ID: <1446216500-14267-1-git-send-email-rkrcmar@redhat.com> (raw)

BSP doesn't get INIT so its apic_arb_prio isn't zeroed after reboot.
BSP won't get lowest priority interrupts until other VCPUs get enough
interrupts to match their pre-reboot apic_arb_prio.

That behavior doesn't fit into KVM's round-robin-like interpretation of
lowest priority delivery ... userspace should KVM_SET_LAPIC on reset, so
just zero apic_arb_prio there.

Reported-by: Yuki Shibuya <shibuya.yk@ncos.nec.co.jp>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 arch/x86/kvm/lapic.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 1b02c44c7b8b..08655020417d 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1924,6 +1924,8 @@ void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu,
 	kvm_make_request(KVM_REQ_EVENT, vcpu);
 	if (ioapic_in_kernel(vcpu->kvm))
 		kvm_rtc_eoi_tracking_restore_one(vcpu);
+
+	vcpu->arch.apic_arb_prio = 0;
 }
 
 void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu)
-- 
2.5.3


             reply	other threads:[~2015-10-30 14:48 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-30 14:48 Radim Krčmář [this message]
2015-11-02 11:57 ` [PATCH] KVM: x86: zero apic_arb_prio on reset Paolo Bonzini

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