From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: KVM: fix i8259 reset irq acking Date: Thu, 14 Aug 2008 20:53:25 -0300 Message-ID: <20080814235325.GA14844@dmt.cnet> References: <20080731171556.GA2644@dmt.cnet> <48A2BA22.70805@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm-devel To: Avi Kivity Return-path: Received: from mx1.redhat.com ([66.187.233.31]:52072 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751433AbYHNXyL (ORCPT ); Thu, 14 Aug 2008 19:54:11 -0400 Content-Disposition: inline In-Reply-To: <48A2BA22.70805@qumranet.com> Sender: kvm-owner@vger.kernel.org List-ID: On Wed, Aug 13, 2008 at 01:40:34PM +0300, Avi Kivity wrote: > Marcelo Tosatti wrote: >> The irq ack during pic reset has three problems: >> >> - Ignores slave/master PIC, using gsi 0-8 for both. >> - Generates an ACK even if the APIC is in control. >> - Depends upon IMR being clear, which is broken if the irq was masked >> at the time it was generated. >> >> The last one causes the BIOS to hang after the first reboot of Windows >> installation, since PIT interrupts stop. >> >> Signed-off-by: Marcelo Tosatti >> >> >> diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c >> index de70499..2b42d48 100644 >> --- a/arch/x86/kvm/i8259.c >> +++ b/arch/x86/kvm/i8259.c >> @@ -195,14 +195,18 @@ int kvm_pic_read_irq(struct kvm *kvm) >> void kvm_pic_reset(struct kvm_kpic_state *s) >> { >> - int irq; >> + int irq, irqbase; >> struct kvm *kvm = s->pics_state->irq_request_opaque; >> - for (irq = 0; irq < PIC_NUM_PINS; irq++) { >> - if (!(s->imr & (1 << irq)) && (s->irr & (1 << irq) || >> - s->isr & (1 << irq))) >> - kvm_notify_acked_irq(kvm, irq); >> - } >> + if (s == &s->pics_state->pics[0]) >> + irqbase = 0; >> + else >> + irqbase = 8; >> + >> + if (!kvm_lapic_enabled(kvm->vcpus[0])) >> > > What if the lapic is enabled and passes through PIC interrupts in EXTINT > mode? > > btw, this will oops if we have no vcpu 0. True. How's this: The irq ack during pic reset has three problems: - Ignores slave/master PIC, using gsi 0-8 for both. - Generates an ACK even if the APIC is in control. - Depends upon IMR being clear, which is broken if the irq was masked at the time it was generated. The last one causes the BIOS to hang after the first reboot of Windows installation, since PIT interrupts stop. Signed-off-by: Marcelo Tosatti diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c index de70499..59a2201 100644 --- a/arch/x86/kvm/i8259.c +++ b/arch/x86/kvm/i8259.c @@ -195,13 +195,23 @@ int kvm_pic_read_irq(struct kvm *kvm) void kvm_pic_reset(struct kvm_kpic_state *s) { - int irq; + int irq, irqbase; struct kvm *kvm = s->pics_state->irq_request_opaque; + struct kvm_vcpu *vcpu0 = kvm->vcpus[0]; + + if (s == &s->pics_state->pics[0]) + irqbase = 0; + else + irqbase = 8; for (irq = 0; irq < PIC_NUM_PINS; irq++) { - if (!(s->imr & (1 << irq)) && (s->irr & (1 << irq) || - s->isr & (1 << irq))) - kvm_notify_acked_irq(kvm, irq); + union ioapic_redir_entry entry; + entry = kvm->arch.vioapic->redirtbl[irq+irqbase]; + if ((vcpu0 && !kvm_lapic_enabled(vcpu0)) || + entry.fields.delivery_mode == IOAPIC_EXTINT) { + if (s->irr & (1 << irq) || s->isr & (1 << irq)) + kvm_notify_acked_irq(kvm, irq+irqbase); + } } s->last_irr = 0; s->irr = 0;