From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53529) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YfROI-0004JJ-EB for qemu-devel@nongnu.org; Tue, 07 Apr 2015 07:09:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YfROF-0008Am-9e for qemu-devel@nongnu.org; Tue, 07 Apr 2015 07:09:58 -0400 Received: from cantor2.suse.de ([195.135.220.15]:47224 helo=mx2.suse.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YfROF-0008Ab-2u for qemu-devel@nongnu.org; Tue, 07 Apr 2015 07:09:55 -0400 Message-ID: <5523BB00.3040404@suse.de> Date: Tue, 07 Apr 2015 13:09:52 +0200 From: =?windows-1252?Q?Andreas_F=E4rber?= MIME-Version: 1.0 References: <1427932716-11800-1-git-send-email-namit@cs.technion.ac.il> <551D3768.9090404@redhat.com> <5523AE38.6000701@suse.de> <5523B2C6.5080601@redhat.com> <5523B518.5050902@suse.de> <5523B755.2080909@redhat.com> In-Reply-To: <5523B755.2080909@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] target-i386: clear bsp bit when designating bsp List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini , qemu-devel@nongnu.org Cc: rth@twiddle.net, mst@redhat.com, nadav.amit@gmail.com, Eduardo Habkost , Nadav Amit Am 07.04.2015 um 12:54 schrieb Paolo Bonzini: > On 07/04/2015 12:44, Andreas F=E4rber wrote: >>>> It can change at runtime, though, if you're using the KVM in-kernel = LAPIC. >> Got a pointer? A quick git-grep doesn't show anything in hw/ or >> kvm-all.c or target-i386/ assigning cpu_index, so it'll always have th= e >> initial value. >=20 > Not cpu_index, s->apicbase's MSR_IA32_APICBASE_BSP bit can change with > KVM in-kernel LAPIC. It cannot change with QEMU's userspace LAPIC. >=20 > Because it can change, you have to call apic_designate_bsp for all CPUs > and not only on CPU 0. Now I'm even more confused. Surely CPUState is initially zero-initialized. Then we designate one as BSP on reset. That should be the same result as designating all non-BSP CPUs, no? The only way that would change is then cpu_index =3D=3D 0 goes away (hot-unplug, not implemented yet), and in that case it would be about designating a different CPU, not about un-designating one. If this is some issue with sync'ing state back and forth before QEMU and KVM then the real issue has not been explained. Andreas --=20 SUSE Linux GmbH, Maxfeldstr. 5, 90409 N=FCrnberg, Germany GF: Felix Imend=F6rffer, Jane Smithard, Jennifer Guild, Dilip Upmanyu, Graham Norton; HRB 21284 (AG N=FCrnberg)