From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: [PATCH] kvm: x86: correctly reset dest_map->vector when restoring LAPIC state Date: Wed, 14 Sep 2016 23:48:32 +0200 Message-ID: <1473889712-13785-1-git-send-email-pbonzini@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Joerg Roedel , David Gilbert , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Return-path: Received: from mail-wm0-f68.google.com ([74.125.82.68]:36335 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753312AbcINVsh (ORCPT ); Wed, 14 Sep 2016 17:48:37 -0400 Sender: kvm-owner@vger.kernel.org List-ID: When userspace sends KVM_SET_LAPIC, KVM schedules a check between the vCPU's IRR and ISR and the IOAPIC redirection table, in order to re-establish the IOAPIC's dest_map (the list of CPUs servicing the real-time clock interrupt with the corresponding vectors). However, __rtc_irq_eoi_tracking_restore_one was forgetting to set dest_map->vectors. Because of this, the IOAPIC did not process the real-time clock interrupt EOI, ioapic->rtc_status.pending_eoi got stuck at a non-zero value, and further RTC interrupts were reported to userspace as coalesced. Fixes: 9e4aabe2bb3454c83dac8139cf9974503ee044db Fixes: 4d99ba898dd0c521ca6cdfdde55c9b58aea3cb3d Cc: Joerg Roedel Cc: David Gilbert Cc: Radim Krčmář Signed-off-by: Paolo Bonzini --- arch/x86/kvm/ioapic.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c index 5f42d038fcb4..c7220ba94aa7 100644 --- a/arch/x86/kvm/ioapic.c +++ b/arch/x86/kvm/ioapic.c @@ -109,6 +109,7 @@ static void __rtc_irq_eoi_tracking_restore_one(struct kvm_vcpu *vcpu) { bool new_val, old_val; struct kvm_ioapic *ioapic = vcpu->kvm->arch.vioapic; + struct dest_map *dest_map = &ioapic->rtc_status.dest_map; union kvm_ioapic_redirect_entry *e; e = &ioapic->redirtbl[RTC_GSI]; @@ -117,16 +118,17 @@ static void __rtc_irq_eoi_tracking_restore_one(struct kvm_vcpu *vcpu) return; new_val = kvm_apic_pending_eoi(vcpu, e->fields.vector); - old_val = test_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map.map); + old_val = test_bit(vcpu->vcpu_id, dest_map->map); if (new_val == old_val) return; if (new_val) { - __set_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map.map); + __set_bit(vcpu->vcpu_id, dest_map->map); + dest_map->vectors[vcpu->vcpu_id] = e->fields.vector; ioapic->rtc_status.pending_eoi++; } else { - __clear_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map.map); + __clear_bit(vcpu->vcpu_id, dest_map->map); ioapic->rtc_status.pending_eoi--; rtc_status_pending_eoi_check_valid(ioapic); } -- 1.8.3.1