From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36391) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bpcpz-0001mp-Tv for qemu-devel@nongnu.org; Thu, 29 Sep 2016 11:01:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bpcpv-0007zn-Qm for qemu-devel@nongnu.org; Thu, 29 Sep 2016 11:01:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41774) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bpcpv-0007z0-Lg for qemu-devel@nongnu.org; Thu, 29 Sep 2016 11:01:23 -0400 Date: Thu, 29 Sep 2016 12:01:19 -0300 From: Eduardo Habkost Message-ID: <20160929150119.GS3877@thinpad.lan.raisama.net> References: <20160929112329.2408-1-rkrcmar@redhat.com> <20160929112329.2408-8-rkrcmar@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20160929112329.2408-8-rkrcmar@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v2 7/7] intel-iommu: keep buggy EIM enabled in 2.7 machine type List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Radim =?utf-8?B?S3LEjW3DocWZ?= Cc: qemu-devel@nongnu.org, Peter Xu , Igor Mammedov , Paolo Bonzini , Richard Henderson , "Michael S. Tsirkin" On Thu, Sep 29, 2016 at 01:23:29PM +0200, Radim Kr=C4=8Dm=C3=A1=C5=99 wro= te: > QEMU 2.7 allowed EIM even in configurations that were forbidden in the > last patch because they were not working, like old KVM or userspace > APIC. In order to keep backward compatibility, we again allow guests t= o > misbehave in non-obvious ways, and make it the default. >=20 > Signed-off-by: Radim Kr=C4=8Dm=C3=A1=C5=99 If you break compatibility and fix it in separate patches, you break bisectability (even for people that are bisecting bugs unrelated to EIM). (But I still don't understand if patch 6/7 really breaks anything, or not.) --=20 Eduardo