From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56584) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YfTZf-0007SH-PY for qemu-devel@nongnu.org; Tue, 07 Apr 2015 09:29:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YfTZb-0006FU-Hc for qemu-devel@nongnu.org; Tue, 07 Apr 2015 09:29:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53071) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YfTZb-0006FA-CT for qemu-devel@nongnu.org; Tue, 07 Apr 2015 09:29:47 -0400 Message-ID: <5523DBC2.2050007@redhat.com> Date: Tue, 07 Apr 2015 15:29:38 +0200 From: Paolo Bonzini 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> <5523BB00.3040404@suse.de> <5523C62E.6010507@suse.de> <5523D90A.1040604@redhat.com> <5523DAEC.6070605@openvz.org> In-Reply-To: <5523DAEC.6070605@openvz.org> 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: "Denis V. Lunev" , =?windows-1252?Q?Andreas_F=E4rbe?= =?windows-1252?Q?r?= , qemu-devel@nongnu.org Cc: Eduardo Habkost , mst@redhat.com, Nadav Amit , Igor Mammedov , nadav.amit@gmail.com, rth@twiddle.net On 07/04/2015 15:26, Denis V. Lunev wrote: > On 07/04/15 16:18, Paolo Bonzini wrote: >> >> >> On 07/04/2015 13:57, Andreas F=E4rber wrote: >>>>> If this is some issue with sync'ing state back and forth before >>>>> QEMU and >>>>> KVM then the real issue has not been explained. >>> Hm, hw/intc/apic_common.c:apic_reset_common() has: >>> >>> bsp =3D cpu_is_bsp(s->cpu); >>> s->apicbase =3D APIC_DEFAULT_ADDRESS | >>> (bsp ? MSR_IA32_APICBASE_BSP : 0) | MSR_IA32_APICBASE_ENABLE= ; >>> >>> What this is doing is really: >>> >>> bsp =3D cpu_get_apic_base(s->cpu->apic_state) & >>> MSR_IA32_APICBASE_BSP; >>> s->apicbase =3D APIC_DEFAULT_ADDRESS | >>> (bsp ? MSR_IA32_APICBASE_BSP : 0) | MSR_IA32_APICBASE_ENABLE= ; >>> >>> Unless I'm missing something, since we are in the APIC device's reset >>> function, this is effectively a twisted way of writing: >>> >>> bsp =3D s->apicbase & MSR_IA32_APICBASE_BSP; >>> s->apicbase =3D APIC_DEFAULT_ADDRESS | >>> (bsp ? MSR_IA32_APICBASE_BSP : 0) | MSR_IA32_APICBASE_ENABLE= ; >> >> Yes, this is more readable. >=20 > just $0.02 :) >=20 > why don't > bsp =3D s->apicbase & MSR_IA32_APICBASE_BSP; > s->apicbase =3D > APIC_DEFAULT_ADDRESS | bsp | MSR_IA32_APICBASE_ENABLE; > in this case. This looks the same from the textual point of view. Yes. Would you like to send a patch? Paolo