Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761372Ab2EQIHn (ORCPT ); Thu, 17 May 2012 04:07:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46946 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759909Ab2EQIHe (ORCPT ); Thu, 17 May 2012 04:07:34 -0400 Date: Thu, 17 May 2012 11:07:31 +0300 From: Gleb Natapov To: Avi Kivity Cc: "Michael S. Tsirkin" , Marcelo Tosatti , x86@kernel.org, kvm@vger.kernel.org, Ingo Molnar , "H. Peter Anvin" , Linus Torvalds , linux-kernel@vger.kernel.org Subject: Re: [PATCHv4 3/5] kvm: host side for eoi optimization Message-ID: <20120517080731.GZ32036@redhat.com> References: <20120516172058.GA22861@amt.cnet> <20120516175856.GD10769@redhat.com> <20120516181500.GA23791@amt.cnet> <20120516182520.GH28798@redhat.com> <20120516182948.GF10769@redhat.com> <20120516183822.GI28798@redhat.com> <20120516190757.GA12113@redhat.com> <20120517072841.GW32036@redhat.com> <20120517074946.GA27995@redhat.com> <4FB4AF6D.9080305@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4FB4AF6D.9080305@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2142 Lines: 51 On Thu, May 17, 2012 at 10:57:33AM +0300, Avi Kivity wrote: > On 05/17/2012 10:49 AM, Michael S. Tsirkin wrote: > > On Thu, May 17, 2012 at 10:28:41AM +0300, Gleb Natapov wrote: > > > On Wed, May 16, 2012 at 10:07:58PM +0300, Michael S. Tsirkin wrote: > > > > > This code is reached from kvm_cpu_get_interrupt(), but this function will > > > > > not be called in above scenario. > > > > > > > > I think I see. So this shall fix it also makes code cleaner > > > > (no -2 hack). Right? kvm_apic_has_interrupt is called correct? > > > > > > > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c > > > > index b4f7013..5a38e34 100644 > > > > --- a/arch/x86/kvm/lapic.c > > > > +++ b/arch/x86/kvm/lapic.c > > > > @@ -1273,8 +1273,12 @@ int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu) > > > > highest_irr = apic_find_highest_irr(apic); > > > > if (highest_irr == -1) > > > > return -1; > > > > - if (((highest_irr & 0xF0) <= apic_get_reg(apic, APIC_PROCPRI))) > > > > - return -2; > > > > + /* Detect interrupt nesting and disable EOI optimization */ > > > > + if ((highest_irr & 0xF0) <= apic_get_reg(apic, APIC_PROCPRI)) { > > > > + if (pv_eoi_enabled(vcpu)) > > > > + pv_eoi_clr_pending(vcpu); > > > > + return -1; > > > > + } > > > > return highest_irr; > > > > } > > > > > > > I do not like it. kvm_apic_has_interrupt() does not suppose to mutate > > > state. > > > > OK, so let's rename it so it's clear it can mutate state? > > > > No, let's refactor this so it makes sense. The {has|get}_interrupt > split is the cause of the problem, I think. We need a single function, > with callbacks that are called when an event happens. The callbacks can > request an irq window exit, inject an interrupt, play with pveoi, or > cause a #vmexit. > Not sure what do you mean here. I kind of like the code we have now, but this may be because I understand it :) -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/