From patchwork Wed Jul 8 17:56:34 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 6750271 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 [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 468B2C05AC for ; Wed, 8 Jul 2015 17:57:03 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 68127205AA for ; Wed, 8 Jul 2015 17:57:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6FDA120595 for ; Wed, 8 Jul 2015 17:57:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759487AbbGHR4z (ORCPT ); Wed, 8 Jul 2015 13:56:55 -0400 Received: from foss.arm.com ([217.140.101.70]:42735 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759456AbbGHR4w (ORCPT ); Wed, 8 Jul 2015 13:56:52 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 77C68390; Wed, 8 Jul 2015 10:57:18 -0700 (PDT) Received: from approximate.cambridge.arm.com (approximate.cambridge.arm.com [10.1.209.148]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2D13A3F317; Wed, 8 Jul 2015 10:56:51 -0700 (PDT) From: Marc Zyngier To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Cc: =?UTF-8?q?Alex=20Benn=C3=A9e?= , Christoffer Dall , Eric Auger , Andre Przywara Subject: [PATCH v2 02/10] arm/arm64: KVM: Move vgic handling to a non-preemptible section Date: Wed, 8 Jul 2015 18:56:34 +0100 Message-Id: <1436378202-20224-3-git-send-email-marc.zyngier@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1436378202-20224-1-git-send-email-marc.zyngier@arm.com> References: <1436378202-20224-1-git-send-email-marc.zyngier@arm.com> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-7.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable 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 As we're about to introduce some serious GIC-poking to the vgic code, it is important to make sure that we're going to poke the part of the GIC that belongs to the CPU we're about to run on (otherwise, we'd end up with some unexpected interrupts firing)... Introducing a non-preemptible section in kvm_arch_vcpu_ioctl_run prevents the problem from occuring. Signed-off-by: Marc Zyngier Reviewed-by: Alex Bennée Reviewed-by: Christoffer Dall --- arch/arm/kvm/arm.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index d605180..1583a34 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -528,10 +528,20 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) if (vcpu->arch.pause) vcpu_pause(vcpu); + /* + * Disarming the background timer must be done in a + * preemptible context, as this call may sleep. + */ kvm_timer_flush_hwstate(vcpu); - kvm_vgic_flush_hwstate(vcpu); + /* + * Preparing the interrupts to be injected also + * involves poking the GIC, which must be done in a + * non-preemptible context. + */ preempt_disable(); + kvm_vgic_flush_hwstate(vcpu); + local_irq_disable(); /* @@ -544,8 +554,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) if (ret <= 0 || need_new_vmid_gen(vcpu->kvm)) { local_irq_enable(); - preempt_enable(); kvm_vgic_sync_hwstate(vcpu); + preempt_enable(); kvm_timer_sync_hwstate(vcpu); continue; } @@ -586,9 +596,11 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) */ kvm_guest_exit(); trace_kvm_exit(kvm_vcpu_trap_get_class(vcpu), *vcpu_pc(vcpu)); - preempt_enable(); kvm_vgic_sync_hwstate(vcpu); + + preempt_enable(); + kvm_timer_sync_hwstate(vcpu); ret = handle_exit(vcpu, run, ret);