From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH v3] enable x2APIC without interrupt remapping under KVM Date: Tue, 30 Jun 2009 20:12:12 +0300 Message-ID: <4A4A476C.2070305@redhat.com> References: <20090629132926.GB20289@redhat.com> <20090630092623.GI20289@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Gleb Natapov , "linux-kernel@vger.kernel.org" , Suresh Siddha , Sheng Yang , "kvm@vger.kernel.org" To: "Eric W. Biederman" Return-path: 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 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: 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.