From patchwork Thu Mar 27 11:30:38 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 3897651 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id C2627BF549 for ; Thu, 27 Mar 2014 11:31:50 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 07362201BA for ; Thu, 27 Mar 2014 11:31:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 34DCE201CE for ; Thu, 27 Mar 2014 11:31:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756174AbaC0Lbh (ORCPT ); Thu, 27 Mar 2014 07:31:37 -0400 Received: from mail-ee0-f50.google.com ([74.125.83.50]:49771 "EHLO mail-ee0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755294AbaC0Laz (ORCPT ); Thu, 27 Mar 2014 07:30:55 -0400 Received: by mail-ee0-f50.google.com with SMTP id c13so2711046eek.23 for ; Thu, 27 Mar 2014 04:30:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=JTDBQ4bagiTNx6hHx1yULqqP3lLAyTElPGOqdVDTzfA=; b=NGmmMER8NlAq+CNGYVu8YY0c72+M2cO8jqZo8eicAtpQb1xjoI+l7BiueF4MY1Iqng AM+gp07w065enBjx3NORuWlWDgUum9Ojb8ahkWmD54jjxuf7bd8mb5D6oQ5iCHQLGbT+ uiL9rzF7mKtgO8ZtOOkdR6ytWbsNhW3R/aUg55MyfSlzuVo6b+1AK49zBx4YieEBnXRX PH1trwP6mR2hvqCsR8Hm13W+41xyHAvyuri0wBTdgVgLxCLVzLfJUGQ+WLMjcAlYyJ7E V0qggmWAu2l7mNOQVp195UVVSFuleYiNaGA7Ohqv19sU7bwhb3EGihuooETX1Gv+ESJm c9kw== X-Received: by 10.14.5.135 with SMTP id 7mr213445eel.86.1395919853942; Thu, 27 Mar 2014 04:30:53 -0700 (PDT) Received: from playground.lan (net-37-117-156-129.cust.vodafonedsl.it. [37.117.156.129]) by mx.google.com with ESMTPSA id m44sm3766164eep.14.2014.03.27.04.30.52 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 27 Mar 2014 04:30:52 -0700 (PDT) From: Paolo Bonzini To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org Subject: [RFC PATCH 5/5] KVM: x86: speed up emulated moves Date: Thu, 27 Mar 2014 12:30:38 +0100 Message-Id: <1395919838-18466-6-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1395919838-18466-1-git-send-email-pbonzini@redhat.com> References: <1395919838-18466-1-git-send-email-pbonzini@redhat.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-7.2 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We can just blindly move all 16 bytes of ctxt->src's value to ctxt->dst. write_register_operand will take care of writing only the lower bytes. Avoiding a call to memcpy (the compiler optimizes it out) gains about 50 cycles on kvm-unit-tests for register-to-register moves, and makes them about as fast as arithmetic instructions. We could perhaps get a larger speedup by moving all instructions _except_ moves out of x86_emulate_insn, removing opcode_len, and replacing the switch statement with an inlined em_mov. Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_emulate.h | 2 +- arch/x86/kvm/emulate.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h index 24ec1216596e..f7b1e45eb753 100644 --- a/arch/x86/include/asm/kvm_emulate.h +++ b/arch/x86/include/asm/kvm_emulate.h @@ -232,7 +232,7 @@ struct operand { union { unsigned long val; u64 val64; - char valptr[sizeof(unsigned long) + 2]; + char valptr[sizeof(sse128_t)]; sse128_t vec_val; u64 mm_val; void *data; diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 94974055d906..4a3584d419e5 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2955,7 +2955,7 @@ static int em_rdpmc(struct x86_emulate_ctxt *ctxt) static int em_mov(struct x86_emulate_ctxt *ctxt) { - memcpy(ctxt->dst.valptr, ctxt->src.valptr, ctxt->op_bytes); + memcpy(ctxt->dst.valptr, ctxt->src.valptr, sizeof(ctxt->src.valptr)); return X86EMUL_CONTINUE; }