From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: [PATCH] KVM: x86: Avoid busy loops over uninjectable pending APIC timers Date: Wed, 20 Mar 2013 16:30:33 -0300 Message-ID: <20130320193033.GB11138@amt.cnet> References: <5144DAC3.7080401@web.de> <20130317084705.GC11223@redhat.com> <51459ECE.2000107@web.de> <20130317104717.GA6117@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kiszka , kvm To: Gleb Natapov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:35273 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751120Ab3CTTdF (ORCPT ); Wed, 20 Mar 2013 15:33:05 -0400 Content-Disposition: inline In-Reply-To: <20130317104717.GA6117@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Sun, Mar 17, 2013 at 12:47:17PM +0200, Gleb Natapov wrote: > On Sun, Mar 17, 2013 at 11:45:34AM +0100, Jan Kiszka wrote: > > On 2013-03-17 09:47, Gleb Natapov wrote: > > > On Sat, Mar 16, 2013 at 09:49:07PM +0100, Jan Kiszka wrote: > > >> From: Jan Kiszka > > >> > > >> If the guest didn't take the last APIC timer interrupt yet and generates > > >> another one on top, e.g. via periodic mode, we do not block the VCPU > > >> even if the guest state is halted. The reason is that > > >> apic_has_pending_timer continues to return a non-zero value. > > >> > > >> Fix this busy loop by taking the IRR content for the LVT vector in > > >> apic_has_pending_timer into account. > > >> > > > Just drop coalescing tacking for lapic interrupt. After posted interrupt > > > will be merged __apic_accept_irq() will not longer return coalescing > > > information, so the code will be dead anyway. > > > > That requires the RTC decoalescing series to go first to avoid a > > regression, no? Then let's postpone this topic for now. > > > Yes, but decoalescing will work only for RTC :( Are you proposing to drop LAPIC interrupt reinjection?