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 X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 07AE9C433E0 for ; Mon, 15 Jun 2020 04:20:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE383206DB for ; Mon, 15 Jun 2020 04:20:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592194804; bh=Y2RvKPnylS/ZWj8tTVA/D7TQVwDwOOA4nHGSoPR4hIA=; h=Date:From:To:Cc:Subject:Reply-To:List-ID:From; b=wv0zDSTaTR7xJr68dzahFXe6GNtFnWrOhWc1kYOuB1u9SOQ1Kqe2dnNYvDGCpLP5z SCpPVt0olqWVZnL4jVUu+xlkudE6pPyQbdWtHDmjQaqRJ+siAseMey2ANg9mk0zoAW g4hC9JUg6ry7iXI0GqKvufSqfviAAaoa6HvREW2U= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727986AbgFOEUD (ORCPT ); Mon, 15 Jun 2020 00:20:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:58572 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725648AbgFOEUC (ORCPT ); Mon, 15 Jun 2020 00:20:02 -0400 Received: from paulmck-ThinkPad-P72.home (50-39-105-78.bvtn.or.frontiernet.net [50.39.105.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5F83C2065F; Mon, 15 Jun 2020 04:20:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592194802; bh=Y2RvKPnylS/ZWj8tTVA/D7TQVwDwOOA4nHGSoPR4hIA=; h=Date:From:To:Cc:Subject:Reply-To:From; b=iNXx7kMRmsVbiFZXPIoKnyhtxEiO3QGJcWi22FmQInh/dEEAQpGlUNURZuWmRRlFe gqTz2E2gD6tLAgXmbWmx7h+kJqtGfvVewP1H+KF+tODRUc0pkx36xHY0vdJa6tGf0X OgvdFrbMw4tLIdOObsEifKBjmwm1yX9gkUVCcrmw= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 464793522F74; Sun, 14 Jun 2020 21:20:02 -0700 (PDT) Date: Sun, 14 Jun 2020 21:20:02 -0700 From: "Paul E. McKenney" To: cai@lca.pw, pbonzini@redhat.com, elver@google.com Cc: linux-kernel@vger.kernel.org Subject: fastpath_t? __no_kcsan? Both? Message-ID: <20200615042002.GA14788@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello! I get the following conflict when rebasing 39a8c47635b0 ("kvm/svm: Disable KCSAN for svm_vcpu_run()") onto v5.8-rc1: <<<<<<< 6c410247efb2d3907b508a2448ab9ab1c86d938c static fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) ======= static __no_kcsan void svm_vcpu_run(struct kvm_vcpu *vcpu) >>>>>>> kvm/svm: Disable KCSAN for svm_vcpu_run() The "natural" resolution would be this: static fastpath_t __no_kcsan void svm_vcpu_run(struct kvm_vcpu *vcpu) But does that make sense? I have dropped this commit for the time being. Please either let me know the proper resolution or submit a fresh patch, your choice. Thanx, Paul ------------------------------------------------------------------------ commit 39a8c47635b00ebf9a3c52d9ca357fff5a8b36e3 Author: Qian Cai Date: Wed Apr 15 11:37:09 2020 -0400 kvm/svm: Disable KCSAN for svm_vcpu_run() For some reasons, running a simple qemu-kvm command with KCSAN will reset AMD hosts. It turns out svm_vcpu_run() could not be instrumented. This commit therefore disables it for now. # /usr/libexec/qemu-kvm -name ubuntu-18.04-server-cloudimg -cpu host -smp 2 -m 2G -hda ubuntu-18.04-server-cloudimg.qcow2 === console output === Kernel 5.6.0-next-20200408+ on an x86_64 hp-dl385g10-05 login: <...host reset...> HPE ProLiant System BIOS A40 v1.20 (03/09/2018) (C) Copyright 1982-2018 Hewlett Packard Enterprise Development LP Early system initialization, please wait... Acked-by: Paolo Bonzini Signed-off-by: Qian Cai Signed-off-by: Paul E. McKenney diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 38f6aee..c6f89e4 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3280,7 +3280,7 @@ static void svm_cancel_injection(struct kvm_vcpu *vcpu) void __svm_vcpu_run(unsigned long vmcb_pa, unsigned long *regs); -static void svm_vcpu_run(struct kvm_vcpu *vcpu) +static __no_kcsan void svm_vcpu_run(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu);