From patchwork Wed Jul 17 08:17:10 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Julien Thierry X-Patchwork-Id: 11047421 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E9AD3912 for ; Wed, 17 Jul 2019 08:19:37 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D66E22870C for ; Wed, 17 Jul 2019 08:19:37 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C95CF28710; Wed, 17 Jul 2019 08:19:37 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 6396E2870C for ; Wed, 17 Jul 2019 08:19:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=9s1uD4Tpk9UyFd+40ZHJ2zn82X4iXoOBlGX0cy4CX6k=; b=V0UMvbDQ9Xji4R/L2nJ+8pcmwy k2nbX3PaQkHldzowKdWjVq2vwaN/0F5TulPXEcJfRfDljYV3qWsWj+B1ooDbJGniZr86NOl0zrNZx OcINVpfiehcyP73wErKc6orsV2v7FKFdkx/rAY1nC9LrgwcjBwZLb+7UP7LwajsECsjIXjF6iCbz/ vFhhAJK7nvTexj4/5b0JLMhkFJg+3TNjX8MRMM7+8nLkvyyqh29n+Gp6XFAn0AxnlgskiWEr+DtCg 7XiaqgWUJaN4Y6oe/8Fjw8Q6JSVj7xaBh04UQXqDqMgOEUmLLzBVLBSfGb/Tlsqs5Ik/lVagqea35 NtwNkLVw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hnfA0-0005TI-Jt; Wed, 17 Jul 2019 08:19:36 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hnf80-0003Ui-QE for linux-arm-kernel@lists.infradead.org; Wed, 17 Jul 2019 08:17:34 +0000 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 1711F1516; Wed, 17 Jul 2019 01:17:32 -0700 (PDT) Received: from e112298-lin.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id EAA223F71A; Wed, 17 Jul 2019 01:19:29 -0700 (PDT) From: Julien Thierry To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v4 7/9] arm/arm64: kvm: pmu: Make overflow handler NMI safe Date: Wed, 17 Jul 2019 09:17:10 +0100 Message-Id: <1563351432-55652-8-git-send-email-julien.thierry@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1563351432-55652-1-git-send-email-julien.thierry@arm.com> References: <1563351432-55652-1-git-send-email-julien.thierry@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190717_011732_924249_27B0DBF2 X-CRM114-Status: GOOD ( 14.26 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, Julien Thierry , peterz@infradead.org, jolsa@redhat.com, Suzuki K Pouloze , will.deacon@arm.com, Christoffer Dall , acme@kernel.org, alexander.shishkin@linux.intel.com, mingo@redhat.com, James Morse , Marc Zyngier , namhyung@kernel.org, sthotton@marvell.com, liwei391@huawei.com, kvmarm@lists.cs.columbia.edu MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP When using an NMI for the PMU interrupt, taking any lock might cause a deadlock. The current PMU overflow handler in KVM takes locks when trying to wake up a vcpu. When overflow handler is called by an NMI, defer the vcpu waking in an irq_work queue. Signed-off-by: Julien Thierry Cc: Christoffer Dall Cc: Marc Zyngier Cc: Will Deacon Cc: Mark Rutland Cc: James Morse Cc: Suzuki K Pouloze Cc: kvmarm@lists.cs.columbia.edu --- include/kvm/arm_pmu.h | 1 + virt/kvm/arm/pmu.c | 25 ++++++++++++++++++++++++- 2 files changed, 25 insertions(+), 1 deletion(-) -- 1.9.1 diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h index 16c769a..8202ed7 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) diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c index 3dd8238..deed8fb 100644 --- a/virt/kvm/arm/pmu.c +++ b/virt/kvm/arm/pmu.c @@ -421,6 +421,22 @@ void kvm_pmu_sync_hwstate(struct kvm_vcpu *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. */ static void kvm_pmu_perf_overflow(struct perf_event *perf_event, @@ -435,7 +451,11 @@ 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); } } @@ -706,6 +726,9 @@ 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; }