From patchwork Fri Aug 7 15:45:38 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 6970591 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id B36059F39D for ; Fri, 7 Aug 2015 15:46:35 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id D3679205E8 for ; Fri, 7 Aug 2015 15:46:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CEC66205E4 for ; Fri, 7 Aug 2015 15:46:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932449AbbHGPp6 (ORCPT ); Fri, 7 Aug 2015 11:45:58 -0400 Received: from foss.arm.com ([217.140.101.70]:43189 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932334AbbHGPp4 (ORCPT ); Fri, 7 Aug 2015 11:45:56 -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 D096E3FB; Fri, 7 Aug 2015 08:45:56 -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 8F96C3F23A; Fri, 7 Aug 2015 08:45:54 -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 v4 02/11] arm/arm64: KVM: Move vgic handling to a non-preemptible section Date: Fri, 7 Aug 2015 16:45:38 +0100 Message-Id: <1438962347-17541-3-git-send-email-marc.zyngier@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1438962347-17541-1-git-send-email-marc.zyngier@arm.com> References: <1438962347-17541-1-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=-7.0 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. Reviewed-by: Alex Bennée Reviewed-by: Christoffer Dall Signed-off-by: Marc Zyngier --- 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 1141d21..f1bf418 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -523,10 +523,20 @@ 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(); /* @@ -539,8 +549,8 @@ 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; } @@ -585,9 +595,11 @@ 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);