From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752806AbcDBOCp (ORCPT ); Sat, 2 Apr 2016 10:02:45 -0400 Received: from mail.kernel.org ([198.145.29.136]:59203 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752316AbcDBOCT (ORCPT ); Sat, 2 Apr 2016 10:02:19 -0400 From: Andy Lutomirski To: X86 ML Cc: Paolo Bonzini , Peter Zijlstra , KVM list , Arjan van de Ven , xen-devel , linux-kernel@vger.kernel.org, Linus Torvalds , Andrew Morton , Borislav Petkov , Andy Lutomirski Subject: [PATCH v5 9/9] x86/msr: Set the return value to zero when native_rdmsr_safe fails Date: Sat, 2 Apr 2016 07:01:40 -0700 Message-Id: <515fb611449a755312a476cfe11675906e7ddf6c.1459605520.git.luto@kernel.org> X-Mailer: git-send-email 2.5.5 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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) -- 2.5.5