From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756189AbZF3Tn7 (ORCPT ); Tue, 30 Jun 2009 15:43:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753166AbZF3Tnv (ORCPT ); Tue, 30 Jun 2009 15:43:51 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:59367 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752859AbZF3Tnu (ORCPT ); Tue, 30 Jun 2009 15:43:50 -0400 To: Gleb Natapov Cc: "linux-kernel\@vger.kernel.org" , Suresh Siddha , Sheng Yang , "kvm\@vger.kernel.org" , "avi\@redhat.com" References: <20090629132926.GB20289@redhat.com> <20090630092623.GI20289@redhat.com> <20090630190307.GE8122@redhat.com> From: ebiederm@xmission.com (Eric W. Biederman) Date: Tue, 30 Jun 2009 12:43:47 -0700 In-Reply-To: <20090630190307.GE8122@redhat.com> (Gleb Natapov's message of "Tue\, 30 Jun 2009 22\:03\:07 +0300") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-XM-SPF: eid=;;;mid=;;;hst=in02.mta.xmission.com;;;ip=76.21.114.89;;;frm=ebiederm@xmission.com;;;spf=neutral X-SA-Exim-Connect-IP: 76.21.114.89 X-SA-Exim-Rcpt-To: gleb@redhat.com, avi@redhat.com, kvm@vger.kernel.org, sheng@linux.intel.com, suresh.b.siddha@intel.com, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-DCC: XMission; sa01 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Gleb Natapov X-Spam-Relay-Country: X-Spam-Report: * -1.8 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -2.6 BAYES_00 BODY: Bayesian spam probability is 0 to 1% * [score: 0.0000] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa01 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 XM_SPF_Neutral SPF-Neutral * 0.4 UNTRUSTED_Relay Comes from a non-trusted relay Subject: Re: [PATCH v3] enable x2APIC without interrupt remapping under KVM X-SA-Exim-Version: 4.2.1 (built Thu, 25 Oct 2007 00:26:12 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Gleb Natapov writes: > Considering that interrupt remapping is fairly new feature > are you saying that hotplug (pci and cpu) on x86 is a horrible > hack on Linux? Just the current cpu hotplug path. >> It is better than nothing but it certainly is not something >> I would expect to work all of the time. >> > Because of horrible code or non-complaint ioapic implementation out > there? If later this is not a big issue for KVM. Both. And even in spec ioapics can't be made to work 100% reliably. >> Interrupt remapping is the one case where we have hardware >> that works according to spec and that works reasonably well. >> > I am sure when there was only one ioapic implementation in existence > it worked according to a spec (and if not spec was changed :)) Give > interrupt remapping some time and than we will see how above statement > holds. What we need for cpu hotplug/unplug is on the tested path now. That is a significant difference. Eric