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 36863C433F5 for ; Thu, 6 Jan 2022 11:48:03 +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:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=K3OANnN/zxI2m14CC4O4AYPS8LIc4og4Uyn2EvXtgLk=; b=ehqEeLiV63pArx OJv1J9MhepixKxTdfVvAAPmS4sZ3VALTSpEjPxSUAa61yx0K0yDqGP9m2j7C8LrqZ6fN+KjzGTUOo UA1tE+N2LpMZoXns42o07uGZA3acyEb3JvumZZxPl7ehgWWSQ3qLnAYNG60cGi8TZNE5xCH05ftmw OoHpVdgHCQEcqTqEShYxEBQ70FniYCO84bwqDVPAbGhAv0ELj7Xw0uHQ9wTfNpRbI5eFaP7nz5jtU Nj1oUTYxtg5OG6yYZ2RTxZfCLXB/zvPwkYMp+/A5PAKmxIpfD2RyZAMnBqspHcl/k6rgoUkmK47Q+ PTNVYyvU0ZAPnbq7qaCA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1n5RED-00HW0g-FG; Thu, 06 Jan 2022 11:46:45 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1n5RE9-00HVyy-Pj for linux-arm-kernel@lists.infradead.org; Thu, 06 Jan 2022 11:46:43 +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 B9AEF12FC; Thu, 6 Jan 2022 03:46:37 -0800 (PST) Received: from monolith.localdoman (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 617643F774; Thu, 6 Jan 2022 03:46:35 -0800 (PST) Date: Thu, 6 Jan 2022 11:46:42 +0000 From: Alexandru Elisei To: Marc Zyngier 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 Message-ID: References: <20211213152309.158462-1-alexandru.elisei@arm.com> <20211213152309.158462-3-alexandru.elisei@arm.com> <871r2fjrmh.wl-maz@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <871r2fjrmh.wl-maz@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220106_034641_979968_0D33CC1F X-CRM114-Status: GOOD ( 24.62 ) 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 Hi Marc, Sorry for the long silence, I didn't manage to get to your comments before going on holiday. On Tue, Dec 14, 2021 at 12:30:30PM +0000, Marc Zyngier wrote: > 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. That's better, will do. Thanks, Alex > > > + > > + 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