From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 901C7C6FA86 for ; Fri, 23 Sep 2022 06:58:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230291AbiIWG6z (ORCPT ); Fri, 23 Sep 2022 02:58:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230006AbiIWG6w (ORCPT ); Fri, 23 Sep 2022 02:58:52 -0400 Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 51EAD11D0C9; Thu, 22 Sep 2022 23:58:51 -0700 (PDT) Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4MYjft0mtwz4xFt; Fri, 23 Sep 2022 16:58:45 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ellerman.id.au; s=201909; t=1663916329; bh=uAgDDCHFgO5WnTB/PX3kiltH+MoaVOlY4LZAn4+ojd0=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=CGRO2nd5HVsZlZziX5awok6Bq3jjzY8rZ8KXBWjYG7SJmZpbcsTAQrszCGzIr2XoJ VJVEyIOeJVxAMUPqP3dq0bvAtm3Tk7um5oIOCZquXQWM29XLhDKBgo6f/BcLtMe0qG BYPV1f09oZqqTIvLjyWMwsT4zo0ZPhr0fxrTiV+pdqyJB0iz3hvzp7GLGyNh3Yt9zV 2rMpU8tJyvZ2NTq0bQUVa1dQb7movhkYZns9vg2MBwFJgBhJobK2U66vckbse4llHo czDNFXkIADQkilGBEocmKDbBuWxUiZL0xIxidbjJwoU6hrgWMo3V2znrei4/eE+eVX U9s6ZbNEr6qvA== From: Michael Ellerman To: isaku.yamahata@intel.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Paolo Bonzini , Sean Christopherson , Thomas Gleixner , Marc Zyngier , Will Deacon Cc: isaku.yamahata@intel.com, isaku.yamahata@gmail.com, Kai Huang , Chao Gao , Atish Patra , Shaokun Zhang , Daniel Lezcano , Huang Ying , Huacai Chen , Dave Hansen , Borislav Petkov , linuxppc-dev@lists.ozlabs.org, Fabiano Rosas Subject: Re: [PATCH v5 27/30] RFC: KVM: powerpc: Move processor compatibility check to hardware setup In-Reply-To: <574ca90fdaec0f37c197d9600d47d48a74f324bd.1663869838.git.isaku.yamahata@intel.com> References: <574ca90fdaec0f37c197d9600d47d48a74f324bd.1663869838.git.isaku.yamahata@intel.com> Date: Fri, 23 Sep 2022 16:58:41 +1000 Message-ID: <8735ci1sri.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org isaku.yamahata@intel.com writes: > From: Isaku Yamahata > > Move processor compatibility check from kvm_arch_processor_compat() into ^ kvm_arch_check_processor_compat() > kvm_arch_hardware_setup(). The check does model name comparison with a > global variable, cur_cpu_spec. There is no point to check it at run time > on all processors. A key detail I had to look up is that both kvm_arch_hardware_setup() and kvm_arch_check_processor_compat() are called from kvm_init(), one after the other. But the latter is called on each CPU. And because the powerpc implementation of kvm_arch_check_processor_compat() just checks a global, there's no need to call it on every CPU. > kvmppc_core_check_processor_compat() checks the global variable. There are > five implementation for it as follows. There are three implementations not five. > arch/powerpc/include/asm/cputable.h: extern struct cpu_spec *cur_cpu_spec; > arch/powerpc/kvm/book3s.c: return 0 > arch/powerpc/kvm/e500.c: strcmp(cur_cpu_spec->cpu_name, "e500v2") > arch/powerpc/kvm/e500mc.c: strcmp(cur_cpu_spec->cpu_name, "e500mc") > strcmp(cur_cpu_spec->cpu_name, "e5500") > strcmp(cur_cpu_spec->cpu_name, "e6500") > > Suggested-by: Sean Christopherson > Signed-off-by: Isaku Yamahata > Cc: linuxppc-dev@lists.ozlabs.org > Cc: Fabiano Rosas > --- > arch/powerpc/kvm/powerpc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c > index 7b56d6ccfdfb..31dc4f231e9d 100644 > --- a/arch/powerpc/kvm/powerpc.c > +++ b/arch/powerpc/kvm/powerpc.c > @@ -444,12 +444,12 @@ int kvm_arch_hardware_enable(void) > > int kvm_arch_hardware_setup(void *opaque) > { > - return 0; > + return kvmppc_core_check_processor_compat(); > } > > int kvm_arch_check_processor_compat(void) > { > - return kvmppc_core_check_processor_compat(); > + return 0; > } The actual change seems OK. I gave it a quick test boot and ran some VMs, everything seems to work as before. Acked-by: Michael Ellerman (powerpc) cheers