From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH 1/3] KVM: emulator: check rex prefix inside decode_register() Date: Mon, 04 Nov 2013 15:04:54 +0100 Message-ID: <5277A986.9070309@redhat.com> References: <1383573163-17865-1-git-send-email-gleb@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Gleb Natapov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:24240 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752539Ab3KDOE5 (ORCPT ); Mon, 4 Nov 2013 09:04:57 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id rA4E4vZW018950 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 4 Nov 2013 09:04:57 -0500 In-Reply-To: <1383573163-17865-1-git-send-email-gleb@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Il 04/11/2013 14:52, Gleb Natapov ha scritto: > All decode_register() callers check if instruction has rex prefix > to properly decode one byte operand. It make sense to move the check > inside. > > Signed-off-by: Gleb Natapov Reviewed-by: Paolo Bonzini I guess you'd like to use Linus's extra week and get it in 3.13? Paolo > --- > arch/x86/kvm/emulate.c | 18 +++++++----------- > 1 file changed, 7 insertions(+), 11 deletions(-) > > diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c > index 282d28c..0bd372f 100644 > --- a/arch/x86/kvm/emulate.c > +++ b/arch/x86/kvm/emulate.c > @@ -785,9 +785,10 @@ static int do_insn_fetch(struct x86_emulate_ctxt *ctxt, > * @highbyte_regs specifies whether to decode AH,CH,DH,BH. > */ > static void *decode_register(struct x86_emulate_ctxt *ctxt, u8 modrm_reg, > - int highbyte_regs) > + int byteop) > { > void *p; > + int highbyte_regs = (ctxt->rex_prefix == 0) && byteop; > > if (highbyte_regs && modrm_reg >= 4 && modrm_reg < 8) > p = (unsigned char *)reg_rmw(ctxt, modrm_reg & 3) + 1; > @@ -1024,7 +1025,6 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt, > struct operand *op) > { > unsigned reg = ctxt->modrm_reg; > - int highbyte_regs = ctxt->rex_prefix == 0; > > if (!(ctxt->d & ModRM)) > reg = (ctxt->b & 7) | ((ctxt->rex_prefix & 1) << 3); > @@ -1046,10 +1046,10 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt, > > op->type = OP_REG; > if (ctxt->d & ByteOp) { > - op->addr.reg = decode_register(ctxt, reg, highbyte_regs); > + op->addr.reg = decode_register(ctxt, reg, true); > op->bytes = 1; > } else { > - op->addr.reg = decode_register(ctxt, reg, 0); > + op->addr.reg = decode_register(ctxt, reg, false); > op->bytes = ctxt->op_bytes; > } > fetch_register_operand(op); > @@ -1082,12 +1082,10 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt, > ctxt->modrm_seg = VCPU_SREG_DS; > > if (ctxt->modrm_mod == 3) { > - int highbyte_regs = ctxt->rex_prefix == 0; > - > op->type = OP_REG; > op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes; > op->addr.reg = decode_register(ctxt, ctxt->modrm_rm, > - highbyte_regs && (ctxt->d & ByteOp)); > + ctxt->d & ByteOp); > if (ctxt->d & Sse) { > op->type = OP_XMM; > op->bytes = 16; > @@ -4117,10 +4115,8 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op, > case OpMem8: > ctxt->memop.bytes = 1; > if (ctxt->memop.type == OP_REG) { > - int highbyte_regs = ctxt->rex_prefix == 0; > - > - ctxt->memop.addr.reg = decode_register(ctxt, ctxt->modrm_rm, > - highbyte_regs); > + ctxt->memop.addr.reg = decode_register(ctxt, > + ctxt->modrm_rm, true); > fetch_register_operand(&ctxt->memop); > } > goto mem_common; >