From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753445Ab3EIJad (ORCPT ); Thu, 9 May 2013 05:30:33 -0400 Received: from mail-we0-f175.google.com ([74.125.82.175]:63922 "EHLO mail-we0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752956Ab3EIJab (ORCPT ); Thu, 9 May 2013 05:30:31 -0400 Message-ID: <518B6CB3.2050208@redhat.com> Date: Thu, 09 May 2013 11:30:27 +0200 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130311 Thunderbird/17.0.4 MIME-Version: 1.0 To: Gleb Natapov CC: linux-kernel@vger.kernel.org, j-nomura@ce.jp.nec.com Subject: Re: [PATCH 3/3] KVM: emulator: emulate SALC References: <1368090967-3204-1-git-send-email-pbonzini@redhat.com> <1368090967-3204-4-git-send-email-pbonzini@redhat.com> <20130509092554.GB32023@redhat.com> In-Reply-To: <20130509092554.GB32023@redhat.com> X-Enigmail-Version: 1.5.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 09/05/2013 11:25, Gleb Natapov ha scritto: > On Thu, May 09, 2013 at 11:16:07AM +0200, Paolo Bonzini wrote: >> This is an almost-undocumented instruction available in 32-bit mode. >> I say "almost" undocumented because AMD documents it in their opcode >> maps just to say that it is unavailable in 64-bit mode (sections >> "A.2.1 One-Byte Opcodes" and "B.3 Invalid and Reassigned Instructions >> in 64-Bit Mode"). >> >> It is roughly equivalent to "sbb %al, %al" except it does not >> set the flags. Use fastop to emulate it, but do not use the opcode >> directly because it would fail if the host is 64-bit! >> >> Reported-by: Jun'ichi Nomura >> Cc: stable@kernel.org # 3.9 >> Signed-off-by: Paolo Bonzini >> --- >> arch/x86/kvm/emulate.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c >> index 210bb4e..f62d4c8 100644 >> --- a/arch/x86/kvm/emulate.c >> +++ b/arch/x86/kvm/emulate.c >> @@ -534,6 +534,9 @@ FOP_SETCC(setle) >> FOP_SETCC(setnle) >> FOP_END; >> >> +FOP_START(salc) "pushf; sbb %al, %al; popf; ret \n\t" > > FOP_RET Ah, I missed that macro. I was mimicking FOP_SETCC which doesn't use it. Will resend. Paolo >> +FOP_END; >> + >> #define __emulate_1op_rax_rdx(ctxt, _op, _suffix, _ex) \ >> do { \ >> unsigned long _tmp; \ >> @@ -3951,7 +3954,8 @@ static const struct opcode opcode_table[256] = { >> G(Src2One | ByteOp, group2), G(Src2One, group2), >> G(Src2CL | ByteOp, group2), G(Src2CL, group2), >> I(DstAcc | SrcImmUByte | No64, em_aam), >> - I(DstAcc | SrcImmUByte | No64, em_aad), N, >> + I(DstAcc | SrcImmUByte | No64, em_aad), >> + F(DstAcc | ByteOp | No64, em_salc), >> I(DstAcc | SrcXLat | ByteOp, em_mov), >> /* 0xD8 - 0xDF */ >> N, E(0, &escape_d9), N, E(0, &escape_db), N, E(0, &escape_dd), N, N, >> -- >> 1.8.1.4 > > -- > Gleb. >