From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH] KVM: x86: Avoid busy loops over uninjectable pending APIC timers Date: Sun, 17 Mar 2013 12:47:17 +0200 Message-ID: <20130317104717.GA6117@redhat.com> References: <5144DAC3.7080401@web.de> <20130317084705.GC11223@redhat.com> <51459ECE.2000107@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Marcelo Tosatti , kvm To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:19037 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756108Ab3CQKrT (ORCPT ); Sun, 17 Mar 2013 06:47:19 -0400 Content-Disposition: inline In-Reply-To: <51459ECE.2000107@web.de> Sender: kvm-owner@vger.kernel.org List-ID: 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 :( -- Gleb.