From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: [PATCH] KVM: PIC: call ack notifiers for irqs that are dropped form irr Date: Fri, 20 Jul 2012 08:58:56 -0300 Message-ID: <20120720115856.GC9832@amt.cnet> References: <20120717115910.GG6345@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, avi@redhat.com To: Gleb Natapov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:3214 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752066Ab2GTMCI (ORCPT ); Fri, 20 Jul 2012 08:02:08 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q6KC271l017907 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 20 Jul 2012 08:02:08 -0400 Content-Disposition: inline In-Reply-To: <20120717115910.GG6345@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, Jul 17, 2012 at 02:59:11PM +0300, Gleb Natapov wrote: > After commit 242ec97c358256 PIT interrupts are no longer delivered after > PIC reset. It happens because PIT injects interrupt only if previous one > was acked, but since on PIC reset it is dropped from irr it will never > be delivered and hence acknowledged. Fix that by calling ack notifier on > PIC reset. > > Signed-off-by: Gleb Natapov > diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c > index 81cf4fa..f09e790 100644 > --- a/arch/x86/kvm/i8259.c > +++ b/arch/x86/kvm/i8259.c > @@ -305,6 +305,7 @@ static void pic_ioport_write(void *opaque, u32 addr, u32 val) > addr &= 1; > if (addr == 0) { > if (val & 0x10) { > + u8 edge_irr = s->irr & ~s->elcr; > s->init4 = val & 1; > s->last_irr = 0; > s->irr &= s->elcr; > @@ -322,6 +323,9 @@ static void pic_ioport_write(void *opaque, u32 addr, u32 val) > if (val & 0x08) > pr_pic_unimpl( > "level sensitive irq not supported"); > + for (irq = 0; irq < PIC_NUM_PINS/2; irq++) > + if (edge_irr & (1 << irq)) > + pic_clear_isr(s, irq); > } else if (val & 0x08) { > if (val & 0x04) > s->poll = 1; > -- > Gleb. Can modify kvm_pic_reset (currently unused BTW) to conform to 9ed049c3b6230b6898 ? It checks for APIC handling interrupts before acking.