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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 F0303C433EF for ; Mon, 3 Jan 2022 21:41:26 +0000 (UTC) Received: from localhost ([::1]:54256 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1n4V53-00043j-U3 for qemu-devel@archiver.kernel.org; Mon, 03 Jan 2022 16:41:25 -0500 Received: from eggs.gnu.org ([209.51.188.92]:60828) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n4V2J-0002N5-NH for qemu-devel@nongnu.org; Mon, 03 Jan 2022 16:38:35 -0500 Received: from [2607:f8b0:4864:20::102e] (port=54244 helo=mail-pj1-x102e.google.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1n4V2I-0000WN-4J for qemu-devel@nongnu.org; Mon, 03 Jan 2022 16:38:35 -0500 Received: by mail-pj1-x102e.google.com with SMTP id mj19so29722946pjb.3 for ; Mon, 03 Jan 2022 13:38:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=0I7XCI61yTJ76Ii81uRxmH9SO5wsJTBXO1PzhBoYFZs=; b=exFFNtPpjaIfVxB7Iub8SDF6/3auWaGD83mxUJT0/ZGAXK1GVUMoooAOxwO/lFgJ8F boxHCsF4b4fXSManx5LoQUQrTSdWCae7lMk27cuYo+xBAV3EwnJcMm5wPz0157dYwm61 Tg1C6GnBgo8SBja1kY3JlqDL8Exj2cdiWHprJgfoX5YcPX4X00x626RJvb0b7JnsA3QG RO6xoQMtGlD2idL4/jo70Wx8NwsHwzavAGI4v4zVp5u3wKeNbDWW/EbzTP9f+oPo4VtM K6e/QnfP6A7EmGiEmveZJo612oE1R7L5IskxMBfaa3WOvIDCZ/pIT8gENOO5Bqb51Jnu EZMw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=0I7XCI61yTJ76Ii81uRxmH9SO5wsJTBXO1PzhBoYFZs=; b=fEkPmWA8utMs9JivjtCapPPNZbhz9hX7wHuUYHSq0T9/VECwgrfqrd2MayPizAVocE HXVFt2AM3YwbGthLoWKl/sMUAJ7CwDSEjGxDsNeHsC4sserRoeFxS96/Q52UqDpdpX1G f8kEKKLcioqKhV2N8FlQs1Urdwvb0zhOjteDPBm0hnBSrizcLW88s/+sa9MxfNiAC/NG vn1X/fd5/1Dt37CDlD7O/IZWgEa4QDNWXW1GMG55aEe3QOs8xt3bnWIr/eirrvteVQNB DFRGpj3K1J8tC5j3MUPdXutiHsXjWWb3FASXH5brfQQf+FQH6HjX4SZOEMM21B7+IH9e mfng== X-Gm-Message-State: AOAM531x/BEauyYO/tNNk0mSASBnB1Su0LyyhqHJ54Gfo4QQk9Ww4TsM za3G1WuKD2x7PDdnCNHrWryJjQ== X-Google-Smtp-Source: ABdhPJyEQCTAQAon5i8yLfRZFdjiKNU7c+zC4j7I8pL5hlBhILEd53kYEmWOVjiQbDiAg4sLlN93wQ== X-Received: by 2002:a17:90b:3509:: with SMTP id ls9mr57646905pjb.5.1641245912655; Mon, 03 Jan 2022 13:38:32 -0800 (PST) Received: from [192.168.1.13] (174-21-75-75.tukw.qwest.net. [174.21.75.75]) by smtp.gmail.com with ESMTPSA id q22sm41672931pfk.27.2022.01.03.13.38.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 03 Jan 2022 13:38:32 -0800 (PST) Subject: Re: [PATCH v2 4/5] target/ppc: keep ins_cnt/cyc_cnt cleared if MMCR0_FC is set To: Daniel Henrique Barboza , qemu-devel@nongnu.org References: <20220103185332.117878-1-danielhb413@gmail.com> <20220103185332.117878-5-danielhb413@gmail.com> From: Richard Henderson Message-ID: <0b9b2a07-4b0c-4095-9365-d95139e182fc@linaro.org> Date: Mon, 3 Jan 2022 13:38:30 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: <20220103185332.117878-5-danielhb413@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Host-Lookup-Failed: Reverse DNS lookup failed for 2607:f8b0:4864:20::102e (failed) Received-SPF: pass client-ip=2607:f8b0:4864:20::102e; envelope-from=richard.henderson@linaro.org; helo=mail-pj1-x102e.google.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-3.354, RCVD_IN_DNSWL_NONE=-0.0001, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-ppc@nongnu.org, clg@kaod.org, david@gibson.dropbear.id.au Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 1/3/22 10:53 AM, Daniel Henrique Barboza wrote: > pmu_update_summaries() is not considering the case where the PMU can be > turned off (i.e. stop counting all events) if MMCR0_FC is set, > regardless of the other frozen counter bits state. This use case was > covered in the late pmc_get_event(), via the also gone pmc_is_inactive(), > that would return an invalid event if MMCR0_FC was set. > > This use case is exercised by the back_to_back_ebbs_test Linux kernel > selftests [1]. As it is today, after enabling EBB exceptions, the test > will report an additional event-based branch being taken and will fail. > Other tests, such as cycles_test.c, will report additional cycles being > calculated in the counters because we're not freezing the PMU quick > enough. > > Fix pmu_update_summaries() by keeping env->ins_cnt and env->cyc_cnt > cleared when MMCR0_FC is set. > > [1] tools/testing/selftests/powerpc/pmu/ebb/back_to_back_ebbs_test.c > > Signed-off-by: Daniel Henrique Barboza > --- > target/ppc/power8-pmu.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/target/ppc/power8-pmu.c b/target/ppc/power8-pmu.c > index 7fc7d91109..73713ca2a3 100644 > --- a/target/ppc/power8-pmu.c > +++ b/target/ppc/power8-pmu.c > @@ -40,6 +40,10 @@ void pmu_update_summaries(CPUPPCState *env) > int ins_cnt = 0; > int cyc_cnt = 0; > > + if (mmcr0 & MMCR0_FC) { > + goto hflags_calc; > + } > + > if (!(mmcr0 & MMCR0_FC14) && mmcr1 != 0) { > target_ulong sel; > > @@ -71,6 +75,7 @@ void pmu_update_summaries(CPUPPCState *env) > ins_cnt |= !(mmcr0 & MMCR0_FC56) << 5; > cyc_cnt |= !(mmcr0 & MMCR0_FC56) << 6; > > + hflags_calc: Good catch, but should be folded into patch 1 to avoid bisection breakage. r~