From patchwork Wed Mar 27 17:11:49 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 2352131 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 9DD0EDFE82 for ; Wed, 27 Mar 2013 17:16:29 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UKtut-000135-Dw; Wed, 27 Mar 2013 17:13:39 +0000 Received: from service87.mimecast.com ([91.220.42.44]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UKtu8-0000n1-5r for linux-arm-kernel@lists.infradead.org; Wed, 27 Mar 2013 17:12:53 +0000 Received: from cam-owa1.Emea.Arm.com (fw-tnat.cambridge.arm.com [217.140.96.21]) by service87.mimecast.com; Wed, 27 Mar 2013 17:12:49 +0000 Received: from e106331-lin.cambridge.arm.com ([10.1.255.212]) by cam-owa1.Emea.Arm.com with Microsoft SMTPSVC(6.0.3790.0); Wed, 27 Mar 2013 17:12:47 +0000 From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 2/5] ARM: KVM: arch_timers: zero CNTVOFF upon return to host Date: Wed, 27 Mar 2013 17:11:49 +0000 Message-Id: <1364404312-4427-3-git-send-email-mark.rutland@arm.com> X-Mailer: git-send-email 1.8.1.1 In-Reply-To: <1364404312-4427-1-git-send-email-mark.rutland@arm.com> References: <1364404312-4427-1-git-send-email-mark.rutland@arm.com> X-OriginalArrivalTime: 27 Mar 2013 17:12:47.0717 (UTC) FILETIME=[4DEBF950:01CE2B0E] X-MC-Unique: 113032717124914601 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130327_131252_507263_0E1024EA X-CRM114-Status: UNSURE ( 9.55 ) 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: Mark Rutland , cdall@cs.columbia.edu, dave.martin@linaro.org, kgene.kim@samsung.com, swarren@wwwdotorg.org, marc.zyngier@arm.com, rob.herring@calxeda.com, santosh.shilimkar@ti.com X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org To use the virtual counters from the host, we need to ensure that CNTVOFF doesn't change unexpectedly. When we change to a guest, we replace the host's CNTVOFF, but we don't restore it when returning to the host. As the host sets CNTVOFF to zero, and never changes it, we can simply zero CNTVOFF when returning to the host. This patch adds said zeroing to the return to host path. Signed-off-by: Mark Rutland Acked-by: Marc Zyngier Cc: Christoffer Dall --- arch/arm/kvm/interrupts_head.S | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S index 3c8f2f0..d43cfb5 100644 --- a/arch/arm/kvm/interrupts_head.S +++ b/arch/arm/kvm/interrupts_head.S @@ -497,6 +497,10 @@ vcpu .req r0 @ vcpu pointer always in r0 add r5, vcpu, r4 strd r2, r3, [r5] + @ Ensure host CNTVCT == CNTPCT + mov r2, #0 + mcrr p15, 4, r2, r2, c14 @ CNTVOFF + 1: #endif @ Allow physical timer/counter access for the host