From mboxrd@z Thu Jan 1 00:00:00 1970 From: Radim =?utf-8?B?S3LEjW3DocWZ?= Subject: Re: Enable more than 255 VCPU support without irq remapping function in the guest Date: Thu, 28 Apr 2016 17:32:51 +0200 Message-ID: <20160428153251.GA17368@potion> References: <571F93CA.40200@intel.com> <571F9487.5090009@siemens.com> <20160426164939.GA18900@potion> <57203B9D.6020402@gmail.com> <57204D28.4070706@siemens.com> <572088D0.7040805@gmail.com> <57208A54.40502@siemens.com> <57216341.80006@gmail.com> <5721B394.9050008@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Yang Zhang , "Lan, Tianyu" , pbonzini@redhat.com, kvm@vger.kernel.org, tglx@linutronix.de, gleb@redhat.com, mst@redhat.com, x86@kernel.org, Peter Xu , Igor Mammedov To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:48072 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752327AbcD1Pc4 (ORCPT ); Thu, 28 Apr 2016 11:32:56 -0400 Content-Disposition: inline In-Reply-To: <5721B394.9050008@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: 2016-04-28 08:54+0200, Jan Kiszka: > On 2016-04-28 03:11, Yang Zhang wrote: >> On 2016/4/27 17:45, Jan Kiszka wrote: >>> On 2016-04-27 11:39, Yang Zhang wrote: >>>> I mean in Tianyu's case, if he doesn't care about to deliver external >>>> interrupt to CPU >255, IR is not required. >>> >>> What matters is the guest OS. See my other reply on this why this >>> doesn't work, even for Linux. >> >> Since there only few devices in his case, set the irq affinity manually >> is enough. You could configure non-IPIs to work, but we want to create options that are hard to break. > Ah, wait - are we talking about emulating the Xeon Phi architecture in > QEMU, accelerated by KVM? Knights Landing will also be manufactured as a CPU, hopefully without many peculiarities. I think we are talking about extending KVM's IR-less x2APIC, when standard x2APIC is the future.