From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH v2 3/4] KVM: ioapic: extract body of kvm_ioapic_set_irq Date: Sun, 23 Mar 2014 09:44:31 +0100 Message-ID: <532E9EEF.2080906@redhat.com> References: <1395394081-16252-1-git-send-email-pbonzini@redhat.com> <1395394081-16252-4-git-send-email-pbonzini@redhat.com> <20140321185858.GA22118@potion.brq.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, gleb@kernel.org, mtosatti@redhat.com, alex.williamson@redhat.com, jan.kiszka@siemens.com To: =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= Return-path: Received: from mail-ee0-f52.google.com ([74.125.83.52]:44701 "EHLO mail-ee0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751288AbaCWIog (ORCPT ); Sun, 23 Mar 2014 04:44:36 -0400 In-Reply-To: <20140321185858.GA22118@potion.brq.redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Il 21/03/2014 19:58, Radim Kr=C4=8Dm=C3=A1=C5=99 ha scritto: >> > + /* >> > + * Return 0 for coalesced interrupts; for edge-triggered interru= pts, >> > + * this only happens if a previous edge has not been delivered d= ue >> > + * do masking. For level interrupts, the remote_irr field tells > (^ to) >> > + * us if the interrupt is waiting for an EOI. > > How do we know we haven't delivered an edge-triggered interrupt when > ioapic_service() always clears this IRR bit? We know we have at least delivered it to the local APIC(s). If it is=20 masked in the ioredirtbl, ioapic_service doesn't clear the IRR. Paolo