From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=148.163.158.5 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793979126; b=OFy03HQBQc7hPks0BhvT5W/hTVVl9R9iOmX4fDEG2mG8JvnsAtQllAAl1GOA0+fapeKu ANZntQ+un8rhTJRTVHKcPGiEILoCNOeFE5r07exq5EWP/y4X9Zb1OyOmOQ4vm0a3tI5p8 LecpwP2hb6Fb+cbmOFARQ1GmhG0eVkhjEKRKkgNh3IznIBTecn9/DJUo8D5FWhg1ZXU4Y pE0/07B+oDP5ADFCPwqSRAmVUUWXrgclUhA5P+fOp8mlbVEJNFY3ypdf3dK2KV6vZ26UL +0uFvIQTg89Ht2GWFw07khlHPbbYXoUD6GO9EpI84YkglmPfatosK9Ts+Zrwph5oKZw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793979126; h=DMARC-Filter:Received:DKIM-Signature:Received:Received:Received: Received:Received:Received:Received:From:To:Cc:Subject:Date: Message-ID:X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding:X-TM-AS-GCONF:X-Proofpoint-Reinject: X-Authority-Analysis:X-Proofpoint-GUID:X-Proofpoint-Spam-Info: X-Proofpoint-ORIG-GUID:X-Proofpoint-Spam-Details-Enc: X-Proofpoint-Virus-Version:X-Proofpoint-Spam-Details; bh=fFR0KdsfK6dJUInFKV8qgHMsYHCXBxTYLlyubzjP+7U=; b=RKzOYJa7BZ+1VwBbsdFhpQ4E7rnLEKtpkVtWMDNc2w0OCjhBsE7X6mEVRuIMARt2xYus mCIvxc9SKfUtBZQR/yehyx6WdXsaouZhNLRDDuU5YZLANa47tJiVTrJylcgxjrQDBBLs3 hWXkRBqB8FAtl9XeSTIOAaeV2SoncGb+xbVzPaJeHv/6a9pjeIDhKdDn5fltOzipmB/ej Ognntfq5IywQmIU+e++q1Uth+Wx9PYXmDOqF7hT9lqL+IAmOL4LHXO1wdzq+UIU5tBfK0 QQbQHvnDi6cCEFsfhQSMx3R87c0ttZj7ddbg8yYNYi8JJRijkVLC4YBEcIzn8QnJYZQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256 header.s=pp1 header.b=r1hBJRts; arc=none smtp.remote-ip=148.163.158.5 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A9BA3606A335; Fri, 6 Nov 2026 15:32:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org A9BA3606A335 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256 header.s=pp1 header.b=r1hBJRts Received: from pps.filterd (m0360072.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 6A6FEEGV2726891; Fri, 6 Nov 2026 15:31:57 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:date:from:in-reply-to:message-id :mime-version:references:subject:to; s=pp1; bh=fFR0KdsfK6dJUInFK V8qgHMsYHCXBxTYLlyubzjP+7U=; b=r1hBJRtsy7tiHTiwht5sigw9PR/+HigHP xoDKc7lVI7cIsYe3ABOjrXm7bKkNKp6SZAfHpw8ieOTmGva4DQDMDuXEJy3Xp6eJ fSPgmQ9Cf9I0WtqFrzaZrt8UND0D3WMQSjVAUvPBgmhayq+elHWT6lKy2xvSoVSg UQpp7IuS7d0RVVBTR7EYR2/TRQvMoxMLCDP3YK4FDSl5zGnx22jVuEwUPtjfzBk7 uQ6qvTBg4kjLPEmp9lVfxt6ZXbF5NDTZG/jOyWuIAH8jgYvGtel5/ilaNvtR1cmy NgUid3BBpLHGWhK59x3rzj3WV7ixi20E0oJl8KHETe+d6WApliehQ== Received: from ppma23.wdc07v.mail.ibm.com (5d.69.3da9.ip4.static.sl-reverse.com [169.61.105.93]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4hs3r9d71u-1 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Fri, 06 Nov 2026 15:31:57 +0000 (GMT) Received: from pps.filterd (ppma23.wdc07v.mail.ibm.com [127.0.0.1]) by ppma23.wdc07v.mail.ibm.com (8.18.1.11/8.18.1.11) with ESMTP id 6A6F50NF3617259; Fri, 6 Nov 2026 15:31:56 GMT Received: from smtprelay06.fra02v.mail.ibm.com ([9.218.2.230]) by ppma23.wdc07v.mail.ibm.com (PPS) with ESMTPS id 4hrdd7ubmq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 06 Nov 2026 15:31:56 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (smtpav02.fra02v.mail.ibm.com [10.20.54.101]) by smtprelay06.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 6A6FVqZT40763814 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 6 Nov 2026 15:31:52 GMT Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AE4A320067; Fri, 6 Nov 2026 15:31:52 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1EBB12005A; Fri, 6 Nov 2026 15:31:50 +0000 (GMT) Received: from li-fbf77acc-29ba-11b2-a85c-e8e934f50a46.ibmuc.com (unknown [9.39.29.160]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 6 Nov 2026 15:31:49 +0000 (GMT) From: Gautam Menghani To: maddy@linux.ibm.com, npiggin@gmail.com, mpe@ellerman.id.au, chleroy@kernel.org, ritesh.list@gmail.com, sshegde@linux.ibm.com, atrajeev@linux.ibm.com, tshah@linux.ibm.com Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH v3 2/3] powerpc/perf: Update prev_count of event to get accurate values Date: Fri, 6 Nov 2026 21:01:33 +0530 Message-ID: <20261106153136.330165-3-gautam@linux.ibm.com> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261106153136.330165-1-gautam@linux.ibm.com> References: <20261106153136.330165-1-gautam@linux.ibm.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Authority-Analysis: v=2.4 cv=LKHz05W9 c=1 sm=1 tr=0 ts=6aedf2ed cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=zJRp6_cAMcgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=sLosXVA8qExDGVDZZrgA:9 X-Proofpoint-GUID: DV5u_7wbKX0YxXxyCfrNalkx-vR1ljw3 X-Proofpoint-Spam-Info: AW1haW4tMjYxMTA2MDA2MCBTYWx0ZWRfX7RWTSPIDiMPv Qu/U71H70lZXT8zt1ai2E/2s7JBNljBgTH7pKWWi2oW5T0AQXxhXkDdevURxHPFaYFvwBppTYjC sBu1Zyy0njrzDgjh1tTqC3QlvJnbeJ4= X-Proofpoint-ORIG-GUID: uEEhRZauucH76cmGafSnT-cpBjgxWxJz X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMTA2MDA2MCBTYWx0ZWRfXyqCSoOBsS/Fy PZHj+SydpqHvJp0rIe8ucEY0dpvq9LgaAeLDNW31JprfLluioy2YESxvK0bJV2PiyNadaktifsq j9nA8Z4gwbHRY450/S/MJpmg7SOBZSWuN2dnmOzmYaAes3N60kHI8RZQO5UoWiUAVU7aHGOawA1 jxR9h5McftWqAFYKQdCooEtlJmpAfYptySPx2ZIqceJU8oUMeOw+m1G5Z84L0v1r0CwRNLw4WoT 5hk4M4+8jH4qndT0teueslyzHEDZci3Yl/oSJrtybVHLN+wtsR7109IZU/MDiPHxBRoCqV4ay3A SAkvsvy0wlwWnvM4KSfoL08u1fGPsooOCV25iPlFN+0U28AQm9sdnrugbcM7c7PROSb4dkoynBP h+D7CAASXyXbWII3Tx5o7159CLheV2nlPq7RmYCf3DLY054LggmnARFLm/oIHkuNDk0ilBJfO9v +KO7SFyEU817o29neeA== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.138,FMLib:17.12.100.49 definitions=2026-11-06_05,2026-11-06_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 spamscore=0 suspectscore=0 lowpriorityscore=0 impostorscore=0 priorityscore=1501 bulkscore=0 clxscore=1015 malwarescore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2611040001 definitions=main-2611060060 When vpa_pmu_read() is called twice while a vCPU is running on the same host cpu, the "event->hw.prev_count" variable returns the same old value on the 2nd read which results in a larger value getting added to event->count. Fix this by updating the event->hw.prev_count every time vpa_pmu_read() is called. Fixes: 176cda0619b6 ("powerpc/perf: Add perf interface to expose vpa counters") Cc: Signed-off-by: Gautam Menghani --- v2 -> v3: 1. Use local64_xchg for atomic update. v1 -> v2: 1. Add stable/fixes tags. arch/powerpc/perf/vpa-pmu.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/powerpc/perf/vpa-pmu.c b/arch/powerpc/perf/vpa-pmu.c index 01d9196fcb0f..3296877eb317 100644 --- a/arch/powerpc/perf/vpa-pmu.c +++ b/arch/powerpc/perf/vpa-pmu.c @@ -132,6 +132,7 @@ static void vpa_pmu_read(struct perf_event *event) prev_data = local64_read(&event->hw.prev_count); new_data = get_counter_data(event); + prev_data = local64_xchg(&event->hw.prev_count, new_data); final_data = new_data - prev_data; local64_add(final_data, &event->count); -- 2.56.0