From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753475Ab3EIJby (ORCPT ); Thu, 9 May 2013 05:31:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:3019 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752956Ab3EIJbx (ORCPT ); Thu, 9 May 2013 05:31:53 -0400 Date: Thu, 9 May 2013 12:31:49 +0300 From: Gleb Natapov To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, j-nomura@ce.jp.nec.com Subject: Re: [PATCH 3/3] KVM: emulator: emulate SALC Message-ID: <20130509093149.GC32023@redhat.com> References: <1368090967-3204-1-git-send-email-pbonzini@redhat.com> <1368090967-3204-4-git-send-email-pbonzini@redhat.com> <20130509092554.GB32023@redhat.com> <518B6CB3.2050208@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <518B6CB3.2050208@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 09, 2013 at 11:30:27AM +0200, Paolo Bonzini wrote: > 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. > I think it does not use it by mistake. > 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. > > -- Gleb.