From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50106) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UwEZE-0007ZH-Rt for qemu-devel@nongnu.org; Mon, 08 Jul 2013 12:45:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UwEZC-0005iP-Nz for qemu-devel@nongnu.org; Mon, 08 Jul 2013 12:45:36 -0400 Message-ID: <51DAECA7.2090405@suse.de> Date: Mon, 08 Jul 2013 18:45:27 +0200 From: =?UTF-8?B?QW5kcmVhcyBGw6RyYmVy?= MIME-Version: 1.0 References: <1373118856-30171-1-git-send-email-aik@ozlabs.ru> <1373118856-30171-19-git-send-email-aik@ozlabs.ru> <20130708010917.GD2696@voom.redhat.com> <51DA8023.20503@suse.de> <51DADF6F.6010006@linux.vnet.ibm.com> In-Reply-To: <51DADF6F.6010006@linux.vnet.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH 18/19] target-ppc: Enhance the CPU node labels for the guest device tree for pseries. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Prerna Saxena Cc: qemu-ppc , qemu-devel@nongnu.org, Alexander Graf Hi, Am 08.07.2013 17:49, schrieb Prerna Saxena: > On 07/08/2013 02:32 PM, Andreas F=C3=A4rber wrote: >> -----BEGIN PGP SIGNED MESSAGE----- >> Hash: SHA1 >> >> Am 08.07.2013 03:09, schrieb David Gibson: >>> On Sat, Jul 06, 2013 at 11:54:15PM +1000, Alexey Kardashevskiy >>> wrote: >>>> @@ -1342,6 +1346,13 @@ static void >>>> ppc_spapr_init(QEMUMachineInitArgs *args)=20 >>>> register_savevm_live(NULL, "spapr/htab", -1, 1,=20 >>>> &savevm_htab_handlers, spapr); >>>> >>>> + /* Ensure that cpu_model is correctly reflected for a KVM >>>> guest */ + if (kvm_enabled() && !strcmp(cpu_model, "host")) {=20 >>>> + asm ("mfpvr %0" + : "=3Dr"(pvr)); + >>>> cpu_model =3D ppc_cpu_alias_by_pvr(pvr); >>> >>> This needs to be protected by an ifdef CONFIG_KVM or similar. If >>> the compiler optimization level is turned down, so that it doesn't=20 >>> recognize that the kvm_enabled() is always false, then this could=20 >>> attempt to compile the ppc asm instructions on an x86 (or >>> whatever) host. >> >> This hunk can be completely replaced by QOM mechanisms - just didn't >> get to replying yet... >=20 > Sorry I already sent out a v2, and only then saw your message. Could yo= u > pls explain how I could use QOM to replace this code block ? Well, in short the thing is it has not much to do with KVM. The KVM-specific host-powerpc64-cpu type is derived from the one you're looking for and thus you can use object_class_get_parent() to obtain the parent type and look at its name - stripping "-" TYPE_POWERPC_CPU from it should be much more efficient but will give you the detailed name including revision. I was planning to propose an alternative patch for th= at. Replacing a concrete model name with its simpler alias is a secondary issue (separate patch) that is not specific to KVM or -cpu host. Compare -cpu POWER8_v1.0 printing .../POWER8_v1.0@0/... presumably. Further, Alex has already applied a patch of his working around the alias table being a rather archaic construct, not intended for frequent use. Instead of adding even more functions that iterate it, we should turn it into a hashtable for efficient lookup. (Note that the cpu_model_str field may contain more than just the model name, it is otherwise unused in softmmu and I was therefore preparing a patch to ban its use to linux-user solely, so the type name seems the most reliable indicator we have and as a bonus no PVR needed for it.) Regards, Andreas --=20 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=C3=BCrnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imend=C3=B6rffer; HRB 16746 AG N=C3=BC= rnberg