From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755328AbaGNLjw (ORCPT ); Mon, 14 Jul 2014 07:39:52 -0400 Received: from mail-wg0-f42.google.com ([74.125.82.42]:53516 "EHLO mail-wg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755210AbaGNLjR (ORCPT ); Mon, 14 Jul 2014 07:39:17 -0400 From: Paolo Bonzini To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org, Bandan Das Subject: [PATCH 13/19] KVM: emulate: do not initialize memopp Date: Mon, 14 Jul 2014 13:38:37 +0200 Message-Id: <1405337923-4776-14-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1405337923-4776-1-git-send-email-pbonzini@redhat.com> References: <1405337923-4776-1-git-send-email-pbonzini@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Bandan Das rip_relative is only set if decode_modrm runs, and if you have ModRM you will also have a memopp. We can then access memopp unconditionally. Note that rip_relative cannot be hoisted up to decode_modrm, or you break "mov $0, xyz(%rip)". Also, move typecast on "out of range value" of mem.ea to decode_modrm. Together, all these optimizations save about 50 cycles on each emulated instructions (4-6%). Signed-off-by: Bandan Das [Fix immediate operands with rip-relative addressing. - Paolo] Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_emulate.h | 5 +++++ arch/x86/kvm/emulate.c | 8 ++++---- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h index 6c808408326f..fcf58cd25ebd 100644 --- a/arch/x86/include/asm/kvm_emulate.h +++ b/arch/x86/include/asm/kvm_emulate.h @@ -295,6 +295,11 @@ struct x86_emulate_ctxt { struct operand dst; int (*execute)(struct x86_emulate_ctxt *ctxt); int (*check_perm)(struct x86_emulate_ctxt *ctxt); + /* + * The following six fields are cleared together, + * the rest are initialized unconditionally in x86_decode_insn + * or elsewhere + */ bool rip_relative; u8 rex_prefix; u8 lock_prefix; diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 08badf638fb0..390400a54a9c 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -1177,6 +1177,9 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt, } } op->addr.mem.ea = modrm_ea; + if (ctxt->ad_bytes != 8) + ctxt->memop.addr.mem.ea = (u32)ctxt->memop.addr.mem.ea; + done: return rc; } @@ -4425,9 +4428,6 @@ done_prefixes: ctxt->memop.addr.mem.seg = ctxt->seg_override; - if (ctxt->memop.type == OP_MEM && ctxt->ad_bytes != 8) - ctxt->memop.addr.mem.ea = (u32)ctxt->memop.addr.mem.ea; - /* * Decode and fetch the source operand: register, memory * or immediate. @@ -4448,7 +4448,7 @@ done_prefixes: rc = decode_operand(ctxt, &ctxt->dst, (ctxt->d >> DstShift) & OpMask); done: - if (ctxt->memopp && ctxt->memopp->type == OP_MEM && ctxt->rip_relative) + if (ctxt->rip_relative) ctxt->memopp->addr.mem.ea += ctxt->_eip; return (rc != X86EMUL_CONTINUE) ? EMULATION_FAILED : EMULATION_OK; -- 1.8.3.1