From patchwork Fri Mar 11 19:06:50 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andy Lutomirski X-Patchwork-Id: 8568671 Return-Path: X-Original-To: patchwork-xen-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id A34129F1C0 for ; Fri, 11 Mar 2016 19:10:39 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id D7C37202B8 for ; Fri, 11 Mar 2016 19:10:38 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 14A9020272 for ; Fri, 11 Mar 2016 19:10:38 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xen.org with esmtp (Exim 4.84) (envelope-from ) id 1aeSPR-0003Cn-Do; Fri, 11 Mar 2016 19:07:37 +0000 Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.84) (envelope-from ) id 1aeSPQ-0003C9-45 for Xen-devel@lists.xen.org; Fri, 11 Mar 2016 19:07:36 +0000 Received: from [85.158.137.68] by server-9.bemta-3.messagelabs.com id 49/87-03814-77713E65; Fri, 11 Mar 2016 19:07:35 +0000 X-Env-Sender: luto@kernel.org X-Msg-Ref: server-6.tower-31.messagelabs.com!1457723253!2320735!1 X-Originating-IP: [198.145.29.136] X-SpamReason: No, hits=0.0 required=7.0 tests= X-StarScan-Received: X-StarScan-Version: 8.11; banners=-,-,- X-VirusChecked: Checked Received: (qmail 8458 invoked from network); 11 Mar 2016 19:07:34 -0000 Received: from mail.kernel.org (HELO mail.kernel.org) (198.145.29.136) by server-6.tower-31.messagelabs.com with DHE-RSA-AES256-GCM-SHA384 encrypted SMTP; 11 Mar 2016 19:07:34 -0000 Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id DBDAB20373; Fri, 11 Mar 2016 19:07:32 +0000 (UTC) Received: from localhost (c-71-202-137-17.hsd1.ca.comcast.net [71.202.137.17]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3AB722035E; Fri, 11 Mar 2016 19:07:32 +0000 (UTC) From: Andy Lutomirski To: X86 ML Date: Fri, 11 Mar 2016 11:06:50 -0800 Message-Id: X-Mailer: git-send-email 2.5.0 In-Reply-To: References: In-Reply-To: References: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Cc: KVM list , Peter Zijlstra , Linus Torvalds , "linux-kernel@vger.kernel.org" , xen-devel , Andy Lutomirski , Paolo Bonzini , Andrew Morton , Arjan van de Ven Subject: [Xen-devel] [PATCH v3 5/5] x86/msr: Set the return value to zero when native_rdmsr_safe fails X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP This will cause unchecked native_rdmsr_safe failures to return deterministic results. Signed-off-by: Andy Lutomirski --- arch/x86/include/asm/msr.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h index 13da359881d7..e97e79f8a22b 100644 --- a/arch/x86/include/asm/msr.h +++ b/arch/x86/include/asm/msr.h @@ -109,7 +109,10 @@ static inline unsigned long long native_read_msr_safe(unsigned int msr, asm volatile("2: rdmsr ; xor %[err],%[err]\n" "1:\n\t" ".section .fixup,\"ax\"\n\t" - "3: mov %[fault],%[err] ; jmp 1b\n\t" + "3: mov %[fault],%[err]\n\t" + "xorl %%eax, %%eax\n\t" + "xorl %%edx, %%edx\n\t" + "jmp 1b\n\t" ".previous\n\t" _ASM_EXTABLE(2b, 3b) : [err] "=r" (*err), EAX_EDX_RET(val, low, high)