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,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 B0755CA9EA0 for ; Sun, 20 Oct 2019 10:12:00 +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 827D9222BD for ; Sun, 20 Oct 2019 10:12:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="m5TaBuZC"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="peYUqeE2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 827D9222BD 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=40zcnFFbir1v3moGXGN0q/y6jeXJ9VzZUqCNTPOhEDg=; b=m5TaBuZCEGsOVQ PK94+mlwIPcLPbqINcal+Czvlxp6x1m4vjrMK90B9jY+2wleSk4uLKRIfkWOtJd0nPxbV+AFEhDhf fewe0rpqImgyWWyz3/1JqwDSltBIAOYvYeDDOXv6FT40p4z7STL8CflQOE4AL2UrSC+/0yJRKrSrn TQnLkZlsRqbCoIyvBFPP18OTymqmtcpbxbtw6OxU162o6/juPqC7H0pa67pecwyMFTrk4xearx4w4 hbrTyvjXmQrWj4O9mDZftC1MaT5Vdu5gRtw1aQ1IvdPrEMqESKmbMqAB1qpRwZtc0CQ7Qc0U0762o XwGgxxwI38k8WyY2CA/A==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iM8Bi-0004Pz-W8; Sun, 20 Oct 2019 10:11:51 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iM8BV-0004Hm-Tn for linux-arm-kernel@lists.infradead.org; Sun, 20 Oct 2019 10:11:39 +0000 Received: from big-swifty.lan (78.163-31-62.static.virginmediabusiness.co.uk [62.31.163.78]) (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 6929D222BD; Sun, 20 Oct 2019 10:11:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571566297; bh=V53P7Vn0aPiKYwrOMap7wcByveXMeM32VmJKA4bI76s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=peYUqeE2CB2w33fmbugervLQNX+GX31Uh5sbOoiIy1LVvBeTnM0OewPJuZ2QHh4fk +p8U85CFm+SrKBF+MQhBhnaWCIHAxHNbgKhplRjH8mHeC3qn+Ke5Lvgat8eFVrafJZ LGMMdfb/RiiK/jb3OMUP3kjM9ATxDcgxa6oOk1bA= From: Marc Zyngier To: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Subject: [PATCH 1/4] KVM: arm64: pmu: Fix cycle counter truncation Date: Sun, 20 Oct 2019 11:11:26 +0100 Message-Id: <20191020101129.2612-2-maz@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191020101129.2612-1-maz@kernel.org> References: <20191020101129.2612-1-maz@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191020_031137_978250_EEB33A3F X-CRM114-Status: GOOD ( 13.48 ) 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: kvm@vger.kernel.org, Suzuki K Poulose , James Morse , Julien Thierry , Andrew Murray , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org 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 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") Reviewed-by: 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