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 X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 C5288C7618E for ; Tue, 23 Jul 2019 08:17:21 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 9A2C320449 for ; Tue, 23 Jul 2019 08:17:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="U56fWqG5" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9A2C320449 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-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=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=mvph9WcbUDYp7Qv0ZUJu8HSeXbRGYnVZvV4RHkjEg/k=; b=U56fWqG5LoPtB7 Db2GeLU2lWKKSFVM0f1qbCkXbKLMd0bzQTijrsOE9SYbfYH4GhKp8364L/uafOXaGFMcPQzKxmRfF rvuAD3KEny7QGebmezl1/KZDQJprEMpgzIjF1dAIXLiFe8TWUOLPpKtWQVQujOfs0bmHNU9R7JeUC jqC4y4EakDItKIdo/3JXoybGuGtpc3FzJ5yn74ZxaAeZbVUJS5S/xajcxwnIVY7o/XJ2D2gU08SFq GGlUNZSOpBDazefajOBdesUrEFAWOA3MHdLkS83fjYlaZ1q0V+jSls26YH+InQgLre4N9tjhg1ShX +F4KIk1v2cg6dHNQgREQ==; 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 1hppz6-00030c-P0; Tue, 23 Jul 2019 08:17:20 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hppz4-0002oi-4X for linux-arm-kernel@lists.infradead.org; Tue, 23 Jul 2019 08:17:19 +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 EF7CD344; Tue, 23 Jul 2019 01:17:13 -0700 (PDT) Received: from [10.1.197.45] (e112298-lin.cambridge.arm.com [10.1.197.45]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8F2393F71F; Tue, 23 Jul 2019 01:17:12 -0700 (PDT) Subject: Re: [PATCH v2] KVM: arm/arm64: Introduce kvm_pmu_vcpu_init() to setup PMU counter idx To: Zenghui Yu , maz@kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org References: <1563437710-30756-1-git-send-email-yuzenghui@huawei.com> From: Julien Thierry Message-ID: Date: Tue, 23 Jul 2019 09:17:09 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <1563437710-30756-1-git-send-email-yuzenghui@huawei.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190723_011718_266874_41A26FF1 X-CRM114-Status: GOOD ( 24.96 ) 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: suzuki.poulose@arm.com, marc.zyngier@arm.com, linux-kernel@vger.kernel.org, james.morse@arm.com, andrew.murray@arm.com, wanghaibin.wang@huawei.com, julien.thierry.kdev@gmail.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Zenghui, On 18/07/2019 09:15, Zenghui Yu wrote: > We use "pmc->idx" and the "chained" bitmap to determine if the pmc is > chained, in kvm_pmu_pmc_is_chained(). But idx might be uninitialized > (and random) when we doing this decision, through a KVM_ARM_VCPU_INIT > ioctl -> kvm_pmu_vcpu_reset(). And the test_bit() against this random > idx will potentially hit a KASAN BUG [1]. > > In general, idx is the static property of a PMU counter that is not > expected to be modified across resets, as suggested by Julien. It > looks more reasonable if we can setup the PMU counter idx for a vcpu > in its creation time. Introduce a new function - kvm_pmu_vcpu_init() > for this basic setup. Oh, and the KASAN BUG will get fixed this way. > > [1] https://www.spinics.net/lists/kvm-arm/msg36700.html > > Fixes: 80f393a23be6 ("KVM: arm/arm64: Support chained PMU counters") > Suggested-by: Andrew Murray > Suggested-by: Julien Thierry > Cc: Marc Zyngier > Signed-off-by: Zenghui Yu > --- > > Changes since v1: > - Introduce kvm_pmu_vcpu_init() in vcpu's creation time, move the > assignment of pmc->idx into it. > - Thus change the subject. The old one is "KVM: arm/arm64: Assign > pmc->idx before kvm_pmu_stop_counter()". > > Julien, I haven't collected your Acked-by into this version. If you're > still happy with the change, please Ack again. Thanks! > Thanks for making the change. This looks good to me: Acked-by: Julien Thierry Thanks, Julien > include/kvm/arm_pmu.h | 2 ++ > virt/kvm/arm/arm.c | 2 ++ > virt/kvm/arm/pmu.c | 18 +++++++++++++++--- > 3 files changed, 19 insertions(+), 3 deletions(-) > > diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h > index 16c769a..6db0304 100644 > --- a/include/kvm/arm_pmu.h > +++ b/include/kvm/arm_pmu.h > @@ -34,6 +34,7 @@ struct kvm_pmu { > 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); > u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu); > +void kvm_pmu_vcpu_init(struct kvm_vcpu *vcpu); > void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu); > void kvm_pmu_vcpu_destroy(struct kvm_vcpu *vcpu); > void kvm_pmu_disable_counter_mask(struct kvm_vcpu *vcpu, u64 val); > @@ -71,6 +72,7 @@ static inline u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu) > { > return 0; > } > +static inline void kvm_pmu_vcpu_init(struct kvm_vcpu *vcpu) {} > static inline void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu) {} > static inline void kvm_pmu_vcpu_destroy(struct kvm_vcpu *vcpu) {} > static inline void kvm_pmu_disable_counter_mask(struct kvm_vcpu *vcpu, u64 val) {} > diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c > index f645c0f..c704fa6 100644 > --- a/virt/kvm/arm/arm.c > +++ b/virt/kvm/arm/arm.c > @@ -340,6 +340,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu) > /* Set up the timer */ > kvm_timer_vcpu_init(vcpu); > > + kvm_pmu_vcpu_init(vcpu); > + > kvm_arm_reset_debug_ptr(vcpu); > > return kvm_vgic_vcpu_init(vcpu); > diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c > index 3dd8238..362a018 100644 > --- a/virt/kvm/arm/pmu.c > +++ b/virt/kvm/arm/pmu.c > @@ -215,6 +215,20 @@ static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc) > } > > /** > + * kvm_pmu_vcpu_init - assign pmu counter idx for cpu > + * @vcpu: The vcpu pointer > + * > + */ > +void kvm_pmu_vcpu_init(struct kvm_vcpu *vcpu) > +{ > + int i; > + struct kvm_pmu *pmu = &vcpu->arch.pmu; > + > + for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) > + pmu->pmc[i].idx = i; > +} > + > +/** > * kvm_pmu_vcpu_reset - reset pmu state for cpu > * @vcpu: The vcpu pointer > * > @@ -224,10 +238,8 @@ void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu) > int i; > struct kvm_pmu *pmu = &vcpu->arch.pmu; > > - for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) { > + for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) > kvm_pmu_stop_counter(vcpu, &pmu->pmc[i]); > - pmu->pmc[i].idx = i; > - } > > bitmap_zero(vcpu->arch.pmu.chained, ARMV8_PMU_MAX_COUNTER_PAIRS); > } > -- Julien Thierry _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel