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 09:11:08 +0100 Message-ID: <5310449C.7040407@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-qa0-f54.google.com ([209.85.216.54]:35555 "EHLO mail-qa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750942AbaB1ILN (ORCPT ); Fri, 28 Feb 2014 03:11:13 -0500 Received: by mail-qa0-f54.google.com with SMTP id w8so331554qac.41 for ; Fri, 28 Feb 2014 00:11:13 -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