Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932458Ab2KZWsx (ORCPT ); Mon, 26 Nov 2012 17:48:53 -0500 Received: from mga14.intel.com ([143.182.124.37]:23268 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932353Ab2KZWsw (ORCPT ); Mon, 26 Nov 2012 17:48:52 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.83,323,1352102400"; d="scan'208";a="172849681" Message-ID: <50B3F1D2.4010200@linux.intel.com> Date: Mon, 26 Nov 2012 14:48:50 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Paolo Bonzini CC: Avi Kivity , Marcelo Tosatti , Gleb Natapov , Linux KVM mailing list , Linux Kernel Mailing List , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Subject: Re: [PATCH] x86, kvm: Remove incorrect redundant assembly constraint References: <1353537681-18759-1-git-send-email-hpa@linux.intel.com> <50B318C5.8090508@redhat.com> In-Reply-To: <50B318C5.8090508@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1821 Lines: 47 On 11/25/2012 11:22 PM, Paolo Bonzini wrote: > Il 21/11/2012 23:41, H. Peter Anvin ha scritto: >> From: "H. Peter Anvin" >> >> In __emulate_1op_rax_rdx, we use "+a" and "+d" which are input/output >> constraints, and *then* use "a" and "d" as input constraints. This is >> incorrect, but happens to work on some versions of gcc. >> >> However, it breaks gcc with -O0 and icc, and may break on future >> versions of gcc. >> >> Reported-and-tested-by: Melanie Blower >> Signed-off-by: H. Peter Anvin >> Link: http://lkml.kernel.org/r/B3584E72CFEBED439A3ECA9BCE67A4EF1B17AF90@FMSMSX107.amr.corp.intel.com >> --- >> arch/x86/kvm/emulate.c | 3 +-- >> 1 file changed, 1 insertion(+), 2 deletions(-) >> >> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c >> index 39171cb..bba39bf 100644 >> --- a/arch/x86/kvm/emulate.c >> +++ b/arch/x86/kvm/emulate.c >> @@ -426,8 +426,7 @@ static void invalidate_registers(struct x86_emulate_ctxt *ctxt) >> _ASM_EXTABLE(1b, 3b) \ >> : "=m" ((ctxt)->eflags), "=&r" (_tmp), \ >> "+a" (*rax), "+d" (*rdx), "+qm"(_ex) \ >> - : "i" (EFLAGS_MASK), "m" ((ctxt)->src.val), \ >> - "a" (*rax), "d" (*rdx)); \ >> + : "i" (EFLAGS_MASK), "m" ((ctxt)->src.val)); \ >> } while (0) >> >> /* instruction has only one source operand, destination is implicit (e.g. mul, div, imul, idiv) */ >> > > Reviewed-by: Paolo Bonzini > Gleb, Marcelo: are you going to apply this or would you prefer I took it in x86/urgent? -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/