From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59310) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a9KWl-00008J-0y for qemu-devel@nongnu.org; Wed, 16 Dec 2015 17:26:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a9KWi-0002CM-Ag for qemu-devel@nongnu.org; Wed, 16 Dec 2015 17:26:30 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55398) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a9KWi-0002CF-2W for qemu-devel@nongnu.org; Wed, 16 Dec 2015 17:26:28 -0500 Date: Wed, 16 Dec 2015 23:26:20 +0100 From: Igor Mammedov Message-ID: <20151216232620.5e1e014b@igors-macbook-pro.local> In-Reply-To: <20151216193902.GM3774@thinpad.lan.raisama.net> References: <1449728144-6223-1-git-send-email-bharata@linux.vnet.ibm.com> <1449728144-6223-3-git-send-email-bharata@linux.vnet.ibm.com> <20151214172949.GC3774@thinpad.lan.raisama.net> <20151215083809.GI18759@in.ibm.com> <20151216175425.7541d545@igors-macbook-pro.local> <20151216193902.GM3774@thinpad.lan.raisama.net> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH v0 2/9] cpu: Store CPU typename in MachineState List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eduardo Habkost Cc: peter.maydell@linaro.org, qemu-devel@nongnu.org, agraf@suse.de, borntraeger@de.ibm.com, Bharata B Rao , pbonzini@redhat.com, afaerber@suse.de, david@gibson.dropbear.id.au On Wed, 16 Dec 2015 17:39:02 -0200 Eduardo Habkost wrote: > On Wed, Dec 16, 2015 at 05:54:25PM +0100, Igor Mammedov wrote: > > On Tue, 15 Dec 2015 14:08:09 +0530 > > Bharata B Rao wrote: > > > > > On Mon, Dec 14, 2015 at 03:29:49PM -0200, Eduardo Habkost wrote: > > > > On Thu, Dec 10, 2015 at 11:45:37AM +0530, Bharata B Rao wrote: > > > > > Storing CPU typename in MachineState lets us to create CPU > > > > > threads for all architectures in uniform manner from > > > > > arch-neutral code. > > > > > > > > > > TODO: Touching only i386 and spapr targets for now > > > > > > > > > > Signed-off-by: Bharata B Rao > > > > > > > > Suggestions: > > > > > > > > * Name the field "cpu_base_type" to indicate it is the base CPU > > > > class name, not the actual CPU class name used when creating > > > > CPUs. > > > > * Put it in MachineClass, as it may be useful for code that > > > > runs before machine->init(), in the future. > > > > > > Ok. > > > > > > > * Maybe make it a CPUClass* field instead of a string? > > > > > > In the current use case, this base cpu type string is being passed > > > to cpu_generic_init(const char *typename, const char *cpu_model) > > > to create boot time CPUs with given typename and cpu_mode. So for > > > now the string makes sense for use case. > > > > > > Making it CPUClass* would necessiate more changes to > > > cpu_generic_init(). > > how about actually leaving it as "cpu_type" and putting in it > > actual cpu type that could be used with device_add(). > > > > that would get rid of keeping and passing around intermediate > > cpu_model. > > Makes sense. We only need to save both typename and cpu_model > today because cpu_generic_init() currently encapsulates three > steps: CPU class lookup + CPU creation + CPU feature parsing. But > we shouldn't need to redo CPU class lookup every time. BTW: Eduardo do you know if QEMU could somehow provide a list of supported CPU types (i.e. not cpumodels) to libvirt? > > We could just split cpu_model once, and save the resulting > CPUClass* + featurestr, instead of saving the full cpu_model > string and parsing it again every time. isn't featurestr as x86/sparc specific? Could we have field in x86_cpu_class/sparc_cpu_class for it and set it when cpu_model is parsed? That way generic cpu_model parser would handle only cpu names and target specific overrides would handle both. > > The only problem is that it would require refactoring multiple > machines/architectures that use a cpu_XXX_init(const char *cpu_model) > helper. >