From patchwork Tue Jan 15 11:20:29 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 1976771 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork2.kernel.org (Postfix) with ESMTP id A5E7BDF264 for ; Tue, 15 Jan 2013 11:23:32 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1Tv4ZO-0000TD-Ax; Tue, 15 Jan 2013 11:20:42 +0000 Received: from service87.mimecast.com ([91.220.42.44]) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1Tv4ZK-0000SH-8D for linux-arm-kernel@lists.infradead.org; Tue, 15 Jan 2013 11:20:38 +0000 Received: from cam-owa2.Emea.Arm.com (fw-tnat.cambridge.arm.com [217.140.96.21]) by service87.mimecast.com; Tue, 15 Jan 2013 11:20:34 +0000 Received: from e102391-lin.cambridge.arm.com ([10.1.255.212]) by cam-owa2.Emea.Arm.com with Microsoft SMTPSVC(6.0.3790.3959); Tue, 15 Jan 2013 11:20:33 +0000 From: Marc Zyngier To: kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Subject: [PATCH] ARM: KVM: avoid add/sub on vcpu pointer Date: Tue, 15 Jan 2013 11:20:29 +0000 Message-Id: <1358248829-13764-1-git-send-email-marc.zyngier@arm.com> X-Mailer: git-send-email 1.8.1 X-OriginalArrivalTime: 15 Jan 2013 11:20:33.0505 (UTC) FILETIME=[559EE510:01CDF312] X-MC-Unique: 113011511203416501 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130115_062038_500878_F1C8847D X-CRM114-Status: UNSURE ( 8.17 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -2.6 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [91.220.42.44 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: c.dall@virtualopensystems.com X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Doing arithmetic on the vcpu pointer can be avoided by using another register as a base. Saves a few instructions on the switch path. Signed-off-by: Marc Zyngier --- arch/arm/kvm/interrupts_head.S | 32 ++++++++++++++------------------ 1 file changed, 14 insertions(+), 18 deletions(-) diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S index 0e423be..d2442f9 100644 --- a/arch/arm/kvm/interrupts_head.S +++ b/arch/arm/kvm/interrupts_head.S @@ -264,11 +264,10 @@ vcpu .req r0 @ vcpu pointer always in r0 str r3, [vcpu, #CP15_OFFSET(c1_CPACR)] str r4, [vcpu, #CP15_OFFSET(c2_TTBCR)] str r5, [vcpu, #CP15_OFFSET(c3_DACR)] - add vcpu, vcpu, #CP15_OFFSET(c2_TTBR0) - strd r6, r7, [vcpu] - add vcpu, vcpu, #CP15_OFFSET(c2_TTBR1) - CP15_OFFSET(c2_TTBR0) - strd r8, r9, [vcpu] - sub vcpu, vcpu, #CP15_OFFSET(c2_TTBR1) + add r2, vcpu, #CP15_OFFSET(c2_TTBR0) + strd r6, r7, [r2] + add r2, vcpu, #CP15_OFFSET(c2_TTBR1) + strd r8, r9, [r2] str r10, [vcpu, #CP15_OFFSET(c10_PRRR)] str r11, [vcpu, #CP15_OFFSET(c10_NMRR)] str r12, [vcpu, #CP15_OFFSET(c0_CSSELR)] @@ -362,11 +361,10 @@ vcpu .req r0 @ vcpu pointer always in r0 ldr r3, [vcpu, #CP15_OFFSET(c1_CPACR)] ldr r4, [vcpu, #CP15_OFFSET(c2_TTBCR)] ldr r5, [vcpu, #CP15_OFFSET(c3_DACR)] - add vcpu, vcpu, #CP15_OFFSET(c2_TTBR0) - ldrd r6, r7, [vcpu] - add vcpu, vcpu, #CP15_OFFSET(c2_TTBR1) - CP15_OFFSET(c2_TTBR0) - ldrd r8, r9, [vcpu] - sub vcpu, vcpu, #CP15_OFFSET(c2_TTBR1) + add r12, vcpu, #CP15_OFFSET(c2_TTBR0) + ldrd r6, r7, [r12] + add r12, vcpu, #CP15_OFFSET(c2_TTBR1) + ldrd r8, r9, [r12] ldr r10, [vcpu, #CP15_OFFSET(c10_PRRR)] ldr r11, [vcpu, #CP15_OFFSET(c10_NMRR)] ldr r12, [vcpu, #CP15_OFFSET(c0_CSSELR)] @@ -479,7 +477,7 @@ vcpu .req r0 @ vcpu pointer always in r0 * for the host. * * Assumes vcpu pointer in vcpu reg - * Clobbers r2-r4 + * Clobbers r2-r5 */ .macro save_timer_state #ifdef CONFIG_KVM_ARM_TIMER @@ -496,9 +494,8 @@ vcpu .req r0 @ vcpu pointer always in r0 mrrc p15, 3, r2, r3, c14 @ CNTV_CVAL ldr r4, =VCPU_TIMER_CNTV_CVAL - add vcpu, vcpu, r4 - strd r2, r3, [vcpu] - sub vcpu, vcpu, r4 + add r5, vcpu, r4 + strd r2, r3, [r5] 1: #endif @@ -513,7 +510,7 @@ vcpu .req r0 @ vcpu pointer always in r0 * for the host. * * Assumes vcpu pointer in vcpu reg - * Clobbers r2-r4 + * Clobbers r2-r5 */ .macro restore_timer_state @ Disallow physical timer access for the guest @@ -534,9 +531,8 @@ vcpu .req r0 @ vcpu pointer always in r0 mcrr p15, 4, r2, r3, c14 @ CNTVOFF ldr r4, =VCPU_TIMER_CNTV_CVAL - add vcpu, vcpu, r4 - ldrd r2, r3, [vcpu] - sub vcpu, vcpu, r4 + add r5, vcpu, r4 + ldrd r2, r3, [r5] mcrr p15, 3, r2, r3, c14 @ CNTV_CVAL isb