From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36006) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZpFVy-0005Dz-CV for qemu-devel@nongnu.org; Thu, 22 Oct 2015 09:02:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZpFVo-0001Ca-Hs for qemu-devel@nongnu.org; Thu, 22 Oct 2015 09:02:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43635) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZpFVo-0001CQ-66 for qemu-devel@nongnu.org; Thu, 22 Oct 2015 09:02:32 -0400 Date: Thu, 22 Oct 2015 16:02:28 +0300 From: "Michael S. Tsirkin" Message-ID: <20151022155947-mutt-send-email-mst@redhat.com> References: <1445510291-8764-1-git-send-email-matthias.lange@kernkonzept.com> <20151022144537-mutt-send-email-mst@redhat.com> <5628D99C.4080902@kernkonzept.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <5628D99C.4080902@kernkonzept.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH] i386/acpi: add _HID to processor nodes List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Matthias Lange Cc: imammedo@redhat.com, rth@twiddle.net, qemu-devel@nongnu.org, ehabkost@redhat.com, pbonzini@redhat.com On Thu, Oct 22, 2015 at 02:42:05PM +0200, Matthias Lange wrote: > On 10/22/2015 01:48 PM, Michael S. Tsirkin wrote: > > On Thu, Oct 22, 2015 at 12:38:11PM +0200, Matthias Lange wrote: > >> Processor nodes created via the acpi/aml framework currently don't > >> feature a _HID string. This patch appends "ACPI0007" as the _HID > >> string to each processor node. > >> > >> Signed-off-by: Matthias Lange > >=20 > > Indeed, it does that. But why? > >=20 > > ACPI0007 Processor Device. This device provides an alternative to > > declaring processors using the > > Processor ASL statement. > > =20 > > And =E2=80=9CDeclaring Processors=E2=80=9D says > >=20 > >=20 > > Each processor in the system must be declared in the ACPI namespace = in > > either the \_SB or \_PR > > scope but not both. Declaration of processors in the \_PR scope is > > required for platforms desiring > > compatibility with ACPI 1.0-based OSPM implementations. Processors a= re > > declared either via the > > ASL Processor statement or the ASL Device statement. A Processor > > definition declares a processor > > object that provides processor configuration information and points = to > > the processor register block > > (P_BLK). A Device definition for a processor is declared using the > > ACPI0007 hardware identifier > > (HID). In this case, processor configuration information is provided > > exclusively by objects in the > > processor device=E2=80=99s object list. >=20 > Thanks for pointing me to the right section. >=20 > > In other words, Processor directive does not need a HID. > > In fact, ACPI 1.0 didn't include the ACPI0007 HID at all. >=20 > Right. But, does Qemu strive for ACPI 1.0 compatibility? Where possible - it's handy for old guests. > And e.g. > seabios also defines processors using the ALS processor statement > including the HID. I don't see it there: [mst@robin seabios]$ git grep ACI0007 [mst@robin seabios]$ > > Please include this info in both the commit log and a code comment. >=20 > Will do. >=20 > Matthias. Not the ACPI spec info. I have that. The answer to my question - the actual motivation for the patch. > >> --- > >> hw/i386/acpi-build.c | 1 + > >> 1 file changed, 1 insertion(+) > >> > >> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c > >> index 95e0c65..95f7bf9 100644 > >> --- a/hw/i386/acpi-build.c > >> +++ b/hw/i386/acpi-build.c > >> @@ -1153,6 +1153,7 @@ build_ssdt(GArray *table_data, GArray *linker, > >> for (i =3D 0; i < acpi_cpus; i++) { > >> dev =3D aml_processor(i, 0, 0, "CP%.02X", i); > >> =20 > >> + aml_append(dev, aml_name_decl("_HID", aml_string("ACPI0= 007"))); > >> method =3D aml_method("_MAT", 0); > >> aml_append(method, aml_return(aml_call1("CPMA", aml_int= (i)))); > >> aml_append(dev, method); > >> --=20 > >> 1.9.1 >=20 >=20 > --=20 > Matthias Lange, matthias.lange@kernkonzept.com, +49 - 351 - 41 88 86 14 >=20 > Kernkonzept GmbH. Sitz: Dresden. Amtsgericht Dresden, HRB 31129. > Gesch=C3=A4ftsf=C3=BChrer: Dr.-Ing. Michael Hohmuth