From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B27E7C43219 for ; Tue, 14 Dec 2021 12:38:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Subject:Cc:To:From:Message-ID:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=sYM4oO544yDxim8tuagBsMKgIFtF9Eg7oWxPxRU7x/Q=; b=clW0gUCsfoWq7M 1hRN5fRNEaXnIohWz8DeTyfoEpzy89cTjbKCzhNiSJFFyS1GZCzJwCKp72XSSurH1IOzVkKU4bPGx L4o1NlutHqeevWyC6DweVrwE6d8t7yjZ6mxmyzHRVybO8vGHFyQp064FRCviQs12UcaT1ip7ZJ0qy k493dClAnquRCNd/XZSOoJNiMVUEvshzvF16nMa20yocQtt2evWREqHCyVUy9BX/t6XEPjU0lrBll tWXKi15V8ZzY2ikftvCaCN0HKpClmPlxNq6iomm0su+26Y1EnAm3wqGBf+3sFXMUPyrFftpfjvxcx XyKan31c3xWgtfWRqYgg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mx72J-00Dxzo-DC; Tue, 14 Dec 2021 12:36:04 +0000 Received: from ams.source.kernel.org ([2604:1380:4601:e00::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mx6x1-00DwH0-9K for linux-arm-kernel@lists.infradead.org; Tue, 14 Dec 2021 12:30:37 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id E12F0B81912; Tue, 14 Dec 2021 12:30:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 92E7CC34601; Tue, 14 Dec 2021 12:30:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1639485032; bh=wtqkn9O+s/VxfCoUXrYBoSFj1AmgnfdkmanmczXY5UA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=p8ksjKphzW5Fj0ZhRCACIEhWExpEqFFLFVnrncjIvijc0Zols3Ri38Zwg/kn/qiJ5 i8NobceVI5N7VmqHxOjKXIgNdh38NCmgaSwXGUfFiB5lbFS+J0SyBRSQNfAbZbf+MT JwVBjDcnNEY4jb5PLBqHZuo9cgut4UZMwl3qSTHWSQMl5SvALcydr2Qcv2uW101ZhJ 7fh2yjs0fs5HrwcZTzUImjMhzh703KrkIiPaTDUUBkSKQQ7rGwJxjMmLulXoyqYYdW 7v6wgzSdxn/8K0fli93QsMFH/kcgQC4symLXyWgT53kNW3/12a0VS9UzWuD7xji4SW OZG4ABbvRLRPQ== Received: from cfbb000407.r.cam.camfibre.uk ([185.219.108.64] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1mx6ww-00C2dH-KR; Tue, 14 Dec 2021 12:30:30 +0000 Date: Tue, 14 Dec 2021 12:30:30 +0000 Message-ID: <871r2fjrmh.wl-maz@kernel.org> From: Marc Zyngier To: Alexandru Elisei Cc: james.morse@arm.com, suzuki.poulose@arm.com, will@kernel.org, mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, tglx@linutronix.de, mingo@redhat.com, peter.maydell@linaro.org Subject: Re: [PATCH v3 2/4] KVM: arm64: Keep a list of probed PMUs In-Reply-To: <20211213152309.158462-3-alexandru.elisei@arm.com> References: <20211213152309.158462-1-alexandru.elisei@arm.com> <20211213152309.158462-3-alexandru.elisei@arm.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: alexandru.elisei@arm.com, james.morse@arm.com, suzuki.poulose@arm.com, will@kernel.org, mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, tglx@linutronix.de, mingo@redhat.com, peter.maydell@linaro.org 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-20211214_043035_662472_2C714437 X-CRM114-Status: GOOD ( 25.31 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, 13 Dec 2021 15:23:07 +0000, Alexandru Elisei wrote: > > The ARM PMU driver calls kvm_host_pmu_init() after probing to tell KVM that > a hardware PMU is available for guest emulation. Heterogeneous systems can > have more than one PMU present, and the callback gets called multiple > times, once for each of them. Keep track of all the PMUs available to KVM, > as they're going to be needed later. > > Signed-off-by: Alexandru Elisei > --- > arch/arm64/kvm/pmu-emul.c | 25 +++++++++++++++++++++++-- > include/kvm/arm_pmu.h | 5 +++++ > 2 files changed, 28 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c > index a5e4bbf5e68f..eb4be96f144d 100644 > --- a/arch/arm64/kvm/pmu-emul.c > +++ b/arch/arm64/kvm/pmu-emul.c > @@ -7,6 +7,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -14,6 +15,9 @@ > #include > #include > > +static LIST_HEAD(arm_pmus); > +static DEFINE_MUTEX(arm_pmus_lock); > + > static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx); > static void kvm_pmu_update_pmc_chained(struct kvm_vcpu *vcpu, u64 select_idx); > static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc); > @@ -742,9 +746,26 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data, > > void kvm_host_pmu_init(struct arm_pmu *pmu) > { > - if (pmu->pmuver != 0 && pmu->pmuver != ID_AA64DFR0_PMUVER_IMP_DEF && > - !kvm_arm_support_pmu_v3() && !is_protected_kvm_enabled()) > + struct arm_pmu_entry *entry; > + > + if (pmu->pmuver == 0 || pmu->pmuver == ID_AA64DFR0_PMUVER_IMP_DEF || > + is_protected_kvm_enabled()) > + return; > + > + mutex_lock(&arm_pmus_lock); > + > + entry = kmalloc(sizeof(*entry), GFP_KERNEL); > + if (!entry) > + goto out_unlock; > + > + if (list_empty(&arm_pmus)) > static_branch_enable(&kvm_arm_pmu_available); I find it slightly dodgy that you switch the static key before actually populating the entry. I'd suggest moving it after the list_add_tail(), and check on list_is_singular() instead. > + > + entry->arm_pmu = pmu; > + list_add_tail(&entry->entry, &arm_pmus); > + > +out_unlock: > + mutex_unlock(&arm_pmus_lock); > } > > static int kvm_pmu_probe_pmuver(void) > diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h > index 90f21898aad8..e249c5f172aa 100644 > --- a/include/kvm/arm_pmu.h > +++ b/include/kvm/arm_pmu.h > @@ -36,6 +36,11 @@ struct kvm_pmu { > struct irq_work overflow_work; > }; > > +struct arm_pmu_entry { > + struct list_head entry; > + struct arm_pmu *arm_pmu; > +}; > + > #define kvm_arm_pmu_irq_initialized(v) ((v)->arch.pmu.irq_num >= VGIC_NR_SGIS) > u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx); > void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, u64 select_idx, u64 val); Thanks, M. -- Without deviation from the norm, progress is not possible. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel