From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH][RFC] Use return value from kvm_set_irq() to re-inject PIT interrupts. Date: Mon, 24 Aug 2009 22:01:50 +0300 Message-ID: <20090824190150.GC11762@redhat.com> References: <20090824120623.GC30093@redhat.com> <20090824163256.GA8653@amt.cnet> <20090824171646.GA11762@redhat.com> <20090824174427.GA10311@amt.cnet> <20090824181905.GB11762@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, avi@redhat.com To: Marcelo Tosatti Return-path: Received: from mx1.redhat.com ([209.132.183.28]:49718 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751724AbZHXTBv (ORCPT ); Mon, 24 Aug 2009 15:01:51 -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 (8.13.8/8.13.8) with ESMTP id n7OJ1rjM016061 for ; Mon, 24 Aug 2009 15:01:53 -0400 Content-Disposition: inline In-Reply-To: <20090824181905.GB11762@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Mon, Aug 24, 2009 at 09:19:05PM +0300, Gleb Natapov wrote: > > > It is obviously wrong thing to do from assigned devices POV. > > > > Thats not entirely clear to me. So what happens if a guest with PIC > > assigned device resets with a pending IRR? The host interrupt line will > > be kept disabled, even though the guest is able to process further > > interrupts? > The host interrupt line will be enabled (assigned device ack notifier > does this) without clearing interrupt condition in assigned device > (guest hasn't acked irq so how can we be sure it ran device's irq > handler?). Host will hang. > Actually, on the second thought, it will not hang. Next time host interrupt handler runs it will disable interrupt once again. -- Gleb.