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=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,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 A2826C10F14 for ; Sun, 6 Oct 2019 10:47:14 +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 7A63A2173B for ; Sun, 6 Oct 2019 10:47:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="NULT4Wwg"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="h6Qx4aJw" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7A63A2173B 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+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: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=YLPB/y6WtJKSgf8Zb5nv2ioJ1spwBaphzx1p2yW651E=; b=NULT4WwgtUB+Ho 07WDxBdWpU4E/U5kpLwkcCadO1w/EeBILu1woGB+2FZfRMwMhGA9Iu95rSHGeJEGO1antVOtrmUpW yPigUaPg1LRmYuQPE/w6lNovBAiCS84QbijkOO8h6E22ezforinbLdi39BMIONbDRHNrI5a5rLIAx QoijoVs3SGgOVbmKzWDSU1UfMhRHTYya/PJCrqhkg1/1i0toXEW+S44A+uQ1SXuYgGqv35UwK4Unk h3H9h8Vik3IXlGVkF1qNYF9h/qU2pxZYY20VMq7gnEQcGMgPQJgQzyjFMuPOL4KMoYnO4HKeQf+rH R3imCoCNC/Q2W0wxDZzQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iH44H-0005hH-Kn; Sun, 06 Oct 2019 10:47:13 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.2 #3 (Red Hat Linux)) id 1iH446-0005Xu-Gp for linux-arm-kernel@lists.infradead.org; Sun, 06 Oct 2019 10:47:04 +0000 Received: from localhost.localdomain (82-132-217-85.dab.02.net [82.132.217.85]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1640E21479; Sun, 6 Oct 2019 10:46:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570358822; bh=BP1l8qRwdBHc2b0glDmUNsamGkZG1dNdWAdZx4mn8yc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=h6Qx4aJw/nWwQAC8L/sKrb93GHAkb1BQJqdEWMG8dvovCAmixwSxGvx4AnecyF0Nw mKAGSs3M3Yy+o6xRhNodMge8uwM5yGuqYNkOn2un/VMl1TaX7AHmC5p9KZa/vDI4ko vH0BxBuzUEBrfz554CNWs9jbo1AJVmzh/Q2zS6xA= From: maz@kernel.org To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org Subject: [PATCH 1/3] KVM: arm64: pmu: Fix cycle counter truncation Date: Sun, 6 Oct 2019 11:46:34 +0100 Message-Id: <20191006104636.11194-2-maz@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191006104636.11194-1-maz@kernel.org> References: <20191006104636.11194-1-maz@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191006_034702_612795_C0C69AE1 X-CRM114-Status: GOOD ( 13.94 ) 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 , Suzuki K Poulose , Marc Zyngier , James Morse , Andrew Murray , Julien Thierry 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 From: Marc Zyngier When a counter is disabled, its value is sampled before the event is being disabled, and the value written back in the shadow register. In that process, the value gets truncated to 32bit, which is adequate for any counter but the cycle counter (defined as a 64bit counter). This obviously results in a corrupted counter, and things like "perf record -e cycles" not working at all when run in a guest... A similar, but less critical bug exists in kvm_pmu_get_counter_value. Make the truncation conditional on the counter not being the cycle counter, which results in a minor code reorganisation. Fixes: 80f393a23be6 ("KVM: arm/arm64: Support chained PMU counters") Cc: Andrew Murray Reported-by: Julien Thierry Signed-off-by: Marc Zyngier --- virt/kvm/arm/pmu.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c index 362a01886bab..c30c3a74fc7f 100644 --- a/virt/kvm/arm/pmu.c +++ b/virt/kvm/arm/pmu.c @@ -146,8 +146,7 @@ u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx) if (kvm_pmu_pmc_is_chained(pmc) && kvm_pmu_idx_is_high_counter(select_idx)) counter = upper_32_bits(counter); - - else if (!kvm_pmu_idx_is_64bit(vcpu, select_idx)) + else if (select_idx != ARMV8_PMU_CYCLE_IDX) counter = lower_32_bits(counter); return counter; @@ -193,7 +192,7 @@ static void kvm_pmu_release_perf_event(struct kvm_pmc *pmc) */ static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc) { - u64 counter, reg; + u64 counter, reg, val; pmc = kvm_pmu_get_canonical_pmc(pmc); if (!pmc->perf_event) @@ -201,16 +200,19 @@ static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc) counter = kvm_pmu_get_pair_counter_value(vcpu, pmc); - if (kvm_pmu_pmc_is_chained(pmc)) { - reg = PMEVCNTR0_EL0 + pmc->idx; - __vcpu_sys_reg(vcpu, reg) = lower_32_bits(counter); - __vcpu_sys_reg(vcpu, reg + 1) = upper_32_bits(counter); + if (pmc->idx == ARMV8_PMU_CYCLE_IDX) { + reg = PMCCNTR_EL0; + val = counter; } else { - reg = (pmc->idx == ARMV8_PMU_CYCLE_IDX) - ? PMCCNTR_EL0 : PMEVCNTR0_EL0 + pmc->idx; - __vcpu_sys_reg(vcpu, reg) = lower_32_bits(counter); + reg = PMEVCNTR0_EL0 + pmc->idx; + val = lower_32_bits(counter); } + __vcpu_sys_reg(vcpu, reg) = val; + + if (kvm_pmu_pmc_is_chained(pmc)) + __vcpu_sys_reg(vcpu, reg + 1) = upper_32_bits(counter); + kvm_pmu_release_perf_event(pmc); } -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel