From patchwork Wed Mar 26 10:31:12 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 333812 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id DA841140084 for ; Wed, 26 Mar 2014 21:31:44 +1100 (EST) Received: from localhost ([::1]:46627 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WSl7W-0006a9-TQ for incoming@patchwork.ozlabs.org; Wed, 26 Mar 2014 06:31:42 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57652) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WSl73-0006Zq-SY for qemu-devel@nongnu.org; Wed, 26 Mar 2014 06:31:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WSl6x-0007mc-RC for qemu-devel@nongnu.org; Wed, 26 Mar 2014 06:31:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41130) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WSl6x-0007mW-JR for qemu-devel@nongnu.org; Wed, 26 Mar 2014 06:31:07 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s2QAV1P3000980 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Wed, 26 Mar 2014 06:31:03 -0400 Received: from redhat.com (vpn1-5-177.ams2.redhat.com [10.36.5.177]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id s2QAUxRK018783; Wed, 26 Mar 2014 06:30:59 -0400 Date: Wed, 26 Mar 2014 12:31:12 +0200 From: "Michael S. Tsirkin" To: Bug 1297651 <1297651@bugs.launchpad.net> Message-ID: <20140326103112.GA20219@redhat.com> References: <20140326064510.5518.72436.malonedeb@chaenomeles.canonical.com> <20140326064510.5518.72436.malonedeb@chaenomeles.canonical.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20140326064510.5518.72436.malonedeb@chaenomeles.canonical.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.12 X-MIME-Autoconverted: from 8bit to quoted-printable by mx1.redhat.com id s2QAV1P3000980 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: robert.hu@intel.com, lersek@redhat.com, qemu-devel@nongnu.org, ehabkost@redhat.com Subject: Re: [Qemu-devel] [Bug 1297651] [NEW] KVM create a win7 guest with Qemu, it boots up fail X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org On Wed, Mar 26, 2014 at 06:45:10AM -0000, Robert Hu wrote: > Public bug reported: > > Environment: > ------------ > Host OS (ia32/ia32e/IA64):ia32e > Guest OS (ia32/ia32e/IA64):ia32e > Guest OS Type (Linux/Windows):Windows > kvm.git Commit:94b3ffcd41a90d2cb0b32ca23aa58a01111d5dc0 > qemu-kvm Commit:839a5547574e57cce62f49bfc50fe1f04b00589a > Host Kernel Version:3.14.0-rc3 > Hardware:Romley_EP, Ivytown_EP, HSW_EP > > > Bug detailed description: > -------------------------- > when create a win7 guest, the guest boot up fail. > > note: > 1. when create win2000, winxp, win2k3, win2k8, guest, the guest boot up fail. > 2. when create win8, win8.1, win2012 guest, the guest boot up fine. > > > Reproduce steps: > ---------------- > 1.create guest > qemu-system-x86_64 -enable-kvm -m 1024 -smp 2 -net none -hda /root/win7.qcow > > > Current result: > ---------------- > win7 guest boot up fail > > Expected result: > ---------------- > win7 guest boot up fine > > Basic root-causing log: > ---------------------- > > This should be a qemu bug > kvm + qemu = result > 94b3ffcd + 839a5547 = bad > 94b3ffcd + 3a87f8b6 = good > > the first bad commit is: > commit 9bcc80cd71892df42605e0c097d85c0237ff45d1 > Author: Laszlo Ersek Thanks for the excellent bug report! > Date: Mon Mar 17 17:05:16 2014 +0100 > > i386/acpi-build: allow more than 255 elements in CPON > > The build_ssdt() function builds a number of AML objects that are related > to CPU hotplug, and whose IDs form a contiguous sequence of APIC IDs. > (APIC IDs are in fact discontiguous, but this is the traditional > interface: build a contiguous sequence from zero up that covers all > possible APIC IDs.) These objects are: > > - a Processor() object for each VCPU, > - a NTFY method, with one branch for each VCPU, > - a CPON package with one element (hotplug status byte) for each VCPU. > > The build_ssdt() function currently limits the *count* of processor > objects, and NTFY branches, and CPON elements, in 0xFF (see the assignment > to "acpi_cpus"). This allows for an inclusive APIC ID range of [0..254]. > This is incorrect, because the highest APIC ID that we otherwise allow a > VCPU to take is 255. > > In order to extend the maximum count to 256, and the traversed APIC ID > range correspondingly to [0..255]: > - the Processor() objects need no change, > - the NTFY method also needs no change, > - the CPON package must be updated, because it is defined with a > DefPackage, and the number of elements in such a package can be at most > 255. We pick a DefVarPackage instead. > > We replace the Op byte, and the encoding of the number of elements. > Compare: > > DefPackage := PackageOp PkgLength NumElements PackageElementList > DefVarPackage := VarPackageOp PkgLength VarNumElements PackageElementList > > PackageOp := 0x12 > VarPackageOp := 0x13 I think I know what's going on here: the specification says: The ASL compiler can emit two different AML opcodes for a Package declaration, either PackageOp or VarPackageOp. For small, fixed-length packages, the PackageOp is used and this opcode is compatible with ACPI 1.0. A VarPackageOp will be emitted if any of the following conditions are true: • The NumElements argument is a TermArg that can only be resolved at runtime. • At compile time, NumElements resolves to a constant that is larger than 255. • The PackageList contains more than 255 initializer elements. So we clearly violate this rule. > NumElements := ByteData > VarNumElements := TermArg => Integer > > The build_append_int() function implements precisely the following TermArg > encodings (a subset of what the ACPI spec describes): > > TermArg := DataObject > DataObject := ComputationalData > ComputationalData := ConstObj | ByteConst | WordConst | DWordConst > directly encoded in the function, with build_append_byte(): > ConstObj := ZeroOp | OneOp > ZeroOp := 0x00 > OneOp := 0x01 > > call to build_append_value(..., 1): > ByteConst := BytePrefix ByteData > BytePrefix := 0x0A > ByteData := 0x00 - 0xFF > > call to build_append_value(..., 2): > WordConst := WordPrefix WordData > WordPrefix := 0x0B > WordData := ByteData[0:7] ByteData[8:15] > > call to build_append_value(..., 4): > DWordConst := DWordPrefix DWordData > DWordPrefix := 0x0C > DWordData := WordData[0:15] WordData[16:31] > > Signed-off-by: Laszlo Ersek > Reviewed-by: Michael S. Tsirkin > Signed-off-by: Michael S. Tsirkin > > ** Affects: qemu > Importance: Undecided > Status: New > The following seems to fix the issue - still testing. Can you confirm please? However the question we should ask is whether it's a good idea to allow hotplug ID values that might make guests fail to boot. How about limiting ACPI_CPU_HOTPLUG_ID_LIMIT to 255? We never allowed > 255 in the past, is it worth the maintainance headaches? diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c index f1054dd..7597517 100644 --- a/hw/i386/acpi-build.c +++ b/hw/i386/acpi-build.c @@ -1055,9 +1055,21 @@ build_ssdt(GArray *table_data, GArray *linker, { GArray *package = build_alloc_array(); - uint8_t op = 0x13; /* VarPackageOp */ + uint8_t op; + + /* + * Note: The ability to create variable-sized packages was first introduced in ACPI 2.0. ACPI 1.0 only + * allowed fixed-size packages with up to 255 elements. + * Windows guests up to win2k8 fail when VarPackageOp is used. + */ + if (acpi_cpus <= 255) { + op = 0x12; /* PackageOp */ + build_append_byte(package, acpi_cpus); /* NumElements */ + } else { + op = 0x13; /* VarPackageOp */ + build_append_int(package, acpi_cpus); /* VarNumElements */ + } - build_append_int(package, acpi_cpus); /* VarNumElements */ for (i = 0; i < acpi_cpus; i++) { uint8_t b = test_bit(i, cpu->found_cpus) ? 0x01 : 0x00; build_append_byte(package, b);