From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH RFC] kvm: ignore apic polarity Date: Fri, 28 Feb 2014 09:10:53 +0100 Message-ID: <5310448D.3020400@redhat.com> References: <20140214211311.GH29329@ERROL.INI.CMU.EDU> <20140214220600.GI29329@ERROL.INI.CMU.EDU> <2CEB9F8C-E983-4182-A514-44EC568E18D8@suse.de> <20140216114151.GB30056@redhat.com> <1392562020.15608.437.camel@ul30vt.home> <20140216162300.GI30056@redhat.com> <20140227170549.GA23037@redhat.com> <20140227214102.GG17184@ERROL.INI.CMU.EDU> <530FBC9F.8080800@redhat.com> <20140228045524.GB29585@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "Gabriel L. Somlo" , Alex Williamson , "kvm@vger.kernel.org" , "eddie.dong@intel.com" , Alexander Graf , "qemu-devel@nongnu.org" To: "Michael S. Tsirkin" Return-path: Received: from mail-qc0-f179.google.com ([209.85.216.179]:62815 "EHLO mail-qc0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750942AbaB1IK7 (ORCPT ); Fri, 28 Feb 2014 03:10:59 -0500 Received: by mail-qc0-f179.google.com with SMTP id m20so66148qcx.24 for ; Fri, 28 Feb 2014 00:10:58 -0800 (PST) In-Reply-To: <20140228045524.GB29585@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Il 28/02/2014 05:55, Michael S. Tsirkin ha scritto: > Why? > > We already have different ACPI tables for TCG vs KVM. > Specifically apic interrupt override flag in MADT is set > for KVM but not TCG. It used to be this way, but bool kvm_allows_irq0_override(void) { return !kvm_irqchip_in_kernel() || kvm_has_gsi_routing(); } means that these days it is usually set for both TCG and KVM. > As KVM hardware differs from TCG, I expect them to move > further apart with time. I don't expect this, because there are some kind of guests that people will unknowingly end up running with TCG---for example libguestfs. So minimizing the differences in hardware between KVM and TCG _is_ a goal. > Or we can do a patch like we did for kvm and ignore polarity, > treating levels as logical rather than physical. Yes. Paolo From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38757) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WJIXD-0008SQ-I2 for qemu-devel@nongnu.org; Fri, 28 Feb 2014 03:11:15 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WJIX5-0005cI-4N for qemu-devel@nongnu.org; Fri, 28 Feb 2014 03:11:07 -0500 Received: from mail-qc0-x230.google.com ([2607:f8b0:400d:c01::230]:62410) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WJIX5-0005cE-02 for qemu-devel@nongnu.org; Fri, 28 Feb 2014 03:10:59 -0500 Received: by mail-qc0-f176.google.com with SMTP id m20so66176qcx.35 for ; Fri, 28 Feb 2014 00:10:58 -0800 (PST) Sender: Paolo Bonzini Message-ID: <5310448D.3020400@redhat.com> Date: Fri, 28 Feb 2014 09:10:53 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <20140214211311.GH29329@ERROL.INI.CMU.EDU> <20140214220600.GI29329@ERROL.INI.CMU.EDU> <2CEB9F8C-E983-4182-A514-44EC568E18D8@suse.de> <20140216114151.GB30056@redhat.com> <1392562020.15608.437.camel@ul30vt.home> <20140216162300.GI30056@redhat.com> <20140227170549.GA23037@redhat.com> <20140227214102.GG17184@ERROL.INI.CMU.EDU> <530FBC9F.8080800@redhat.com> <20140228045524.GB29585@redhat.com> In-Reply-To: <20140228045524.GB29585@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH RFC] kvm: ignore apic polarity List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Alex Williamson , "kvm@vger.kernel.org" , "eddie.dong@intel.com" , "qemu-devel@nongnu.org" , Alexander Graf , "Gabriel L. Somlo" Il 28/02/2014 05:55, Michael S. Tsirkin ha scritto: > Why? > > We already have different ACPI tables for TCG vs KVM. > Specifically apic interrupt override flag in MADT is set > for KVM but not TCG. It used to be this way, but bool kvm_allows_irq0_override(void) { return !kvm_irqchip_in_kernel() || kvm_has_gsi_routing(); } means that these days it is usually set for both TCG and KVM. > As KVM hardware differs from TCG, I expect them to move > further apart with time. I don't expect this, because there are some kind of guests that people will unknowingly end up running with TCG---for example libguestfs. So minimizing the differences in hardware between KVM and TCG _is_ a goal. > Or we can do a patch like we did for kvm and ignore polarity, > treating levels as logical rather than physical. Yes. Paolo