From patchwork Tue Jan 26 15:15:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 12047093 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0DB3C433DB for ; Tue, 26 Jan 2021 15:17:38 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5B3A623109 for ; Tue, 26 Jan 2021 15:17:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5B3A623109 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version: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=VMBofDERu+i4P5VEiI08AuKJQ6aHHsvPOY+LzdgMZvU=; b=N8CMXlsPu5kKUoXYhkom2ZLVn PBJD47cIeiXL6W6dmj8sr1Bx9F0oW3MSdvco1WHX43GZ1uI2miNpQf+jy6JgTRKbuJ4prQTA5cS8K lWbn+BKI62RvIEFlvY0f6eHwgs60RYttlFCOiL4b5sLb9CkV1mBOqu++wqr0xULpd9ObVo9q/u3mz PSOCGLiBIy9hLdUbe8wD58IEIbuTEkaoOdjZFHP0ZInWO1EDw9Y8pQsydIseZsQHRlT+FfFFTXfNh 1n9PkJhyltZla6mmHBPgYZjOm6Y3kAEOsAcW2y2SwPnR7YZ3ssTgqR2426vPD3Z0y2jsis4LF7qTC /0Lt0IrVA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l4Q4o-00013L-1I; Tue, 26 Jan 2021 15:16:18 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l4Q4g-00011b-LH for linux-arm-kernel@lists.infradead.org; Tue, 26 Jan 2021 15:16:12 +0000 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B82CC23109; Tue, 26 Jan 2021 15:16:09 +0000 (UTC) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1l4Q4e-00A9nZ-29; Tue, 26 Jan 2021 15:16:08 +0000 From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu Subject: [PATCH 1/2] KVM: arm64: Turn kvm_arm_support_pmu_v3() into a static key Date: Tue, 26 Jan 2021 15:15:20 +0000 Message-Id: <20210126151521.2958688-2-maz@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210126151521.2958688-1-maz@kernel.org> References: <20210126151521.2958688-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, andre.przywara@arm.com, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210126_101610_844228_7C5BDC69 X-CRM114-Status: GOOD ( 18.28 ) 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: Andre Przywara , kernel-team@android.com, James Morse , Julien Thierry , Suzuki K Poulose Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org We currently find out about the presence of a HW PMU (or the handling of that PMU by perf, which amounts to the same thing) in a fairly roundabout way, by checking the number of counters available to perf. That's good enough for now, but we will soon need to find about about that on paths where perf is out of reach (in the world switch). Instead, let's turn kvm_arm_support_pmu_v3() into a static key. Signed-off-by: Marc Zyngier --- arch/arm64/kvm/perf.c | 10 ++++++++++ arch/arm64/kvm/pmu-emul.c | 10 ---------- include/kvm/arm_pmu.h | 9 +++++++-- 3 files changed, 17 insertions(+), 12 deletions(-) diff --git a/arch/arm64/kvm/perf.c b/arch/arm64/kvm/perf.c index d45b8b9a4415..198fa4266b2d 100644 --- a/arch/arm64/kvm/perf.c +++ b/arch/arm64/kvm/perf.c @@ -11,6 +11,8 @@ #include +DEFINE_STATIC_KEY_FALSE(kvm_arm_pmu_available); + static int kvm_is_in_guest(void) { return kvm_get_running_vcpu() != NULL; @@ -48,6 +50,14 @@ static struct perf_guest_info_callbacks kvm_guest_cbs = { int kvm_perf_init(void) { + /* + * Check if HW_PERF_EVENTS are supported by checking the number of + * hardware performance counters. This could ensure the presence of + * a physical PMU and CONFIG_PERF_EVENT is selected. + */ + if (perf_num_counters() > 0) + static_branch_enable(&kvm_arm_pmu_available); + return perf_register_guest_info_callbacks(&kvm_guest_cbs); } diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index 4ad66a532e38..44d500706ab9 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -813,16 +813,6 @@ u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1) return val & mask; } -bool kvm_arm_support_pmu_v3(void) -{ - /* - * Check if HW_PERF_EVENTS are supported by checking the number of - * hardware performance counters. This could ensure the presence of - * a physical PMU and CONFIG_PERF_EVENT is selected. - */ - return (perf_num_counters() > 0); -} - int kvm_arm_pmu_v3_enable(struct kvm_vcpu *vcpu) { if (!kvm_vcpu_has_pmu(vcpu)) diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h index 8dcb3e1477bc..6fd3cda608e4 100644 --- a/include/kvm/arm_pmu.h +++ b/include/kvm/arm_pmu.h @@ -13,6 +13,13 @@ #define ARMV8_PMU_CYCLE_IDX (ARMV8_PMU_MAX_COUNTERS - 1) #define ARMV8_PMU_MAX_COUNTER_PAIRS ((ARMV8_PMU_MAX_COUNTERS + 1) >> 1) +DECLARE_STATIC_KEY_FALSE(kvm_arm_pmu_available); + +static __always_inline bool kvm_arm_support_pmu_v3(void) +{ + return static_branch_likely(&kvm_arm_pmu_available); +} + #ifdef CONFIG_HW_PERF_EVENTS struct kvm_pmc { @@ -47,7 +54,6 @@ void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val); void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val); void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data, u64 select_idx); -bool kvm_arm_support_pmu_v3(void); int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr); int kvm_arm_pmu_v3_get_attr(struct kvm_vcpu *vcpu, @@ -87,7 +93,6 @@ static inline void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val) {} static inline void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val) {} static inline void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data, u64 select_idx) {} -static inline bool kvm_arm_support_pmu_v3(void) { return false; } static inline int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr) {