From patchwork Wed Aug 19 13:34:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandru Elisei X-Patchwork-Id: 11724179 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 17157138C for ; Wed, 19 Aug 2020 13:35:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0460620866 for ; Wed, 19 Aug 2020 13:35:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728594AbgHSNd5 (ORCPT ); Wed, 19 Aug 2020 09:33:57 -0400 Received: from foss.arm.com ([217.140.110.172]:36962 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728531AbgHSNdk (ORCPT ); Wed, 19 Aug 2020 09:33:40 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id EF6A71396; Wed, 19 Aug 2020 06:33:39 -0700 (PDT) Received: from monolith.localdoman (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D647C3F71F; Wed, 19 Aug 2020 06:33:37 -0700 (PDT) From: Alexandru Elisei To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: mark.rutland@arm.com, maz@kernel.org, will@kernel.org, catalin.marinas@arm.com, swboyd@chromium.org, sumit.garg@linaro.org, Julien Thierry , Julien Thierry , Marc Zyngier , Will Deacon , James Morse , Suzuki K Pouloze , kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Subject: [PATCH v6 5/7] KVM: arm64: pmu: Make overflow handler NMI safe Date: Wed, 19 Aug 2020 14:34:17 +0100 Message-Id: <20200819133419.526889-6-alexandru.elisei@arm.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200819133419.526889-1-alexandru.elisei@arm.com> References: <20200819133419.526889-1-alexandru.elisei@arm.com> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Julien Thierry kvm_vcpu_kick() is not NMI safe. When the overflow handler is called from NMI context, defer waking the vcpu to an irq_work queue. Cc: Julien Thierry Cc: Marc Zyngier Cc: Will Deacon Cc: Mark Rutland Cc: Catalin Marinas Cc: James Morse Cc: Suzuki K Pouloze Cc: kvm@vger.kernel.org Cc: kvmarm@lists.cs.columbia.edu Signed-off-by: Julien Thierry Signed-off-by: Alexandru Elisei --- arch/arm64/kvm/pmu-emul.c | 25 ++++++++++++++++++++++++- include/kvm/arm_pmu.h | 1 + 2 files changed, 25 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index f0d0312c0a55..30268397ed06 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -433,6 +433,22 @@ void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu) kvm_pmu_update_state(vcpu); } +/** + * When perf interrupt is an NMI, we cannot safely notify the vcpu corresponding + * to the event. + * This is why we need a callback to do it once outside of the NMI context. + */ +static void kvm_pmu_perf_overflow_notify_vcpu(struct irq_work *work) +{ + struct kvm_vcpu *vcpu; + struct kvm_pmu *pmu; + + pmu = container_of(work, struct kvm_pmu, overflow_work); + vcpu = kvm_pmc_to_vcpu(&pmu->pmc[0]); + + kvm_vcpu_kick(vcpu); +} + /** * When the perf event overflows, set the overflow status and inform the vcpu. */ @@ -465,7 +481,11 @@ static void kvm_pmu_perf_overflow(struct perf_event *perf_event, if (kvm_pmu_overflow_status(vcpu)) { kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu); - kvm_vcpu_kick(vcpu); + + if (!in_nmi()) + kvm_vcpu_kick(vcpu); + else + irq_work_queue(&vcpu->arch.pmu.overflow_work); } cpu_pmu->pmu.start(perf_event, PERF_EF_RELOAD); @@ -764,6 +784,9 @@ static int kvm_arm_pmu_v3_init(struct kvm_vcpu *vcpu) return ret; } + init_irq_work(&vcpu->arch.pmu.overflow_work, + kvm_pmu_perf_overflow_notify_vcpu); + vcpu->arch.pmu.created = true; return 0; } diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h index 6db030439e29..dbf4f08d42e5 100644 --- a/include/kvm/arm_pmu.h +++ b/include/kvm/arm_pmu.h @@ -27,6 +27,7 @@ struct kvm_pmu { bool ready; bool created; bool irq_level; + struct irq_work overflow_work; }; #define kvm_arm_pmu_v3_ready(v) ((v)->arch.pmu.ready)