From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42915) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z7n6Q-0006f1-Cv for qemu-devel@nongnu.org; Wed, 24 Jun 2015 12:00:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z7n6O-0007dY-0y for qemu-devel@nongnu.org; Wed, 24 Jun 2015 12:00:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44742) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z7n6N-0007dF-Io for qemu-devel@nongnu.org; Wed, 24 Jun 2015 12:00:39 -0400 Message-ID: <558AD421.80100@redhat.com> Date: Wed, 24 Jun 2015 18:00:33 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <20150623150828.GD3134@thinpad.lan.raisama.net> <20150623173048-mutt-send-email-mst@redhat.com> <20150623155832.GE3134@thinpad.lan.raisama.net> <55898637.6080804@suse.de> <20150623162555.GL30318@redhat.com> <20150623183115-mutt-send-email-mst@redhat.com> <20150623164204.GM30318@redhat.com> <20150623231818-mutt-send-email-mst@redhat.com> <20150624141651.GS3134@thinpad.lan.raisama.net> <558AC0FB.6090608@redhat.com> <20150624155823.GX3134@thinpad.lan.raisama.net> In-Reply-To: <20150624155823.GX3134@thinpad.lan.raisama.net> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 0/2] target-i386: "custom" CPU model + script to dump existing CPU models List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eduardo Habkost Cc: mimu@linux.vnet.ibm.com, "Michael S. Tsirkin" , qemu-devel@nongnu.org, Alexander Graf , borntraeger@de.ibm.com, Igor Mammedov , Jiri Denemark , =?windows-1252?Q?Andreas_F=E4rber?= , rth@twiddle.net On 24/06/2015 17:58, Eduardo Habkost wrote: > > 3) regarding "enforce", there are indeed some cases where it would break: > > > > - Haswell/Broadwell CPU model after TSX removal > > > > - qemu64 with KVM > > > > - pretty much everything including qemu64 with TCG > > - Everything involving KVM CPUID features, that change depending on the > kernel version. > > - Intel CPU models that had VMX enabled in older machine-types, > and may or may not have VMX enabled depending on kernel VMX nesting > configuration. > > > So libvirt here could allow _now_ the user to specify enforce, either > > via XML or via qemu.conf (or via XML + a default specified via qemu.conf). > > More precisely, libvirt would emulate "enforce" mode by checking the > "filtered-features", because "enforce" error messages are not > machine-friendly. Even better, because it would let libvirt special-case stuff like TSX, VMX and SVM. Paolo