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 862EEC28D13 for ; Mon, 22 Aug 2022 13:48:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235377AbiHVNsd (ORCPT ); Mon, 22 Aug 2022 09:48:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35346 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235310AbiHVNsa (ORCPT ); Mon, 22 Aug 2022 09:48:30 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9BA7BBE1A for ; Mon, 22 Aug 2022 06:48:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=YF7MJpPCJtc8Urz7rYZCvMK8j3cGw0f0gRKAs00wVEk=; b=QHfWlkzVLdI+AGdCPDZQKGS/DU qV0mVroQeBjGW53Rpmo62vsSxsuhyEu9O4pnjkgNJQR7atycHNLELQh+er8s9KQB7mcBtJBm1mH7V HxVCgrQYpiOnecQwX+q5gW3aRf0+eN/B6OqYVsoWHSr81tK8i2IhpXTX3mL0NP38EoUAfqPM3FKqt ttoil8b4LrgLvyVx1u1q6aGgU8UpEjWYUDqeB1WVw66fQ8yvlsKiIxyxX8d1rHj62ZssNEr4N/nfp a8UZVGH3h2sgF/1ycqMudCam+NCYhhf9mgu4CG8SIFkooaNNEesrVyU746Vo+MidkZ/04saPEuWx1 QcAegKMA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=worktop.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1oQ7mn-00565A-V9; Mon, 22 Aug 2022 13:48:14 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 817749804A3; Mon, 22 Aug 2022 15:48:12 +0200 (CEST) Date: Mon, 22 Aug 2022 15:48:12 +0200 From: Peter Zijlstra To: "Liang, Kan" Cc: acme@redhat.com, linux-kernel@vger.kernel.org, alexander.shishkin@linux.intel.com, ak@linux.intel.com, Jianfeng Gao Subject: Re: [RESEND PATCH] perf/x86/intel: Fix unchecked MSR access error for Alder Lake N Message-ID: References: <20220818181530.2355034-1-kan.liang@linux.intel.com> <80eea4f7-bb1e-ebb9-37db-9317b8d9c28f@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <80eea4f7-bb1e-ebb9-37db-9317b8d9c28f@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 22, 2022 at 09:28:31AM -0400, Liang, Kan wrote: > > > On 2022-08-19 10:38 a.m., Peter Zijlstra wrote: > > On Thu, Aug 18, 2022 at 11:15:30AM -0700, kan.liang@linux.intel.com wrote: > >> From: Kan Liang > >> > >> For some Alder Lake N machine, the below unchecked MSR access error may be > >> triggered. > >> > >> [ 0.088017] rcu: Hierarchical SRCU implementation. > >> [ 0.088017] unchecked MSR access error: WRMSR to 0x38f (tried to write > >> 0x0001000f0000003f) at rIP: 0xffffffffb5684de8 (native_write_msr+0x8/0x30) > >> [ 0.088017] Call Trace: > >> [ 0.088017] > >> [ 0.088017] __intel_pmu_enable_all.constprop.46+0x4a/0xa0 > > > > FWIW, I seem to get the same error when booting KVM on my ADL. I'm > > fairly sure the whole CPUID vs vCPU thing is a trainwreck. > > We will enhance the CPUID to address the issues. Hopefully, we can have > them supported in the next generation. How!? A vCPU can readily migrate between a big and small CPU. There is no way the guest can sanely program the (v)MSRs and expect it to work.