From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753169AbZF3RMO (ORCPT ); Tue, 30 Jun 2009 13:12:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752741AbZF3RL7 (ORCPT ); Tue, 30 Jun 2009 13:11:59 -0400 Received: from mx2.redhat.com ([66.187.237.31]:35802 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752709AbZF3RL6 (ORCPT ); Tue, 30 Jun 2009 13:11:58 -0400 Message-ID: <4A4A476C.2070305@redhat.com> Date: Tue, 30 Jun 2009 20:12:12 +0300 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1b3pre) Gecko/20090513 Fedora/3.0-2.3.beta2.fc11 Thunderbird/3.0b2 MIME-Version: 1.0 To: "Eric W. Biederman" CC: Gleb Natapov , "linux-kernel@vger.kernel.org" , Suresh Siddha , Sheng Yang , "kvm@vger.kernel.org" Subject: Re: [PATCH v3] enable x2APIC without interrupt remapping under KVM References: <20090629132926.GB20289@redhat.com> <20090630092623.GI20289@redhat.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/30/2009 07:44 PM, Eric W. Biederman wrote: >>> To support that seriously you need interrupt remapping. >>> >>> >> Can you explain why? >> > > Because ioapics don't fully function according to spec, > and the interrupt code on the hotplug path is a horrible > terrible broken hack for ioapics. > > It is better than nothing but it certainly is not something > I would expect to work all of the time. > Can you elaborate? For kvm guests, the hardware is reasonably will implemented and if not we will fix it. We need not cripple a feature just because some hardware is broken. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.