From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 38CB83612C3 for ; Tue, 10 Feb 2026 11:10:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.168.131 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770721807; cv=none; b=tEAacj3hDt7inqpc+2b9e37NJF1rdXompGQFsfnPNcI0PVvfLE6jdgSb0BRefhEzvU+VUaV498JIDLu/2QrmjiX4RWzbUEAJsEY22BTmeIxPMd5mhUproqYLX+QKf8O41XjBkM3kF8tRz83n0y8nQ00bDqmgTe0J3ouRIiTD3wk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770721807; c=relaxed/simple; bh=1w8xc8VCus6Qr0Wfc6mOnjPJ5XW3KYBH6lwESXiLGzU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=lE46/DmaIdib5bC3Qe3pVwqGxUZR8DipMQYxrIph/jUeojVgwKynGBgbUav2qmguZacD/uG8n8xRtObu9UME07UUXY/LC649YGP2VaB6O2PxSnXrX50V1ONd1D137lgZsaU1U1uuvU8IUrtdaff3vuf/A5Z2tksT+q8ipD/wR5g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oss.qualcomm.com; spf=pass smtp.mailfrom=oss.qualcomm.com; dkim=pass (2048-bit key) header.d=qualcomm.com header.i=@qualcomm.com header.b=fZnNimaS; dkim=pass (2048-bit key) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.b=ErPUtMJ2; arc=none smtp.client-ip=205.220.168.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oss.qualcomm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=oss.qualcomm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=qualcomm.com header.i=@qualcomm.com header.b="fZnNimaS"; dkim=pass (2048-bit key) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.b="ErPUtMJ2" Received: from pps.filterd (m0279865.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 61A7Z5Fw2169318 for ; Tue, 10 Feb 2026 11:10:05 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qualcomm.com; h= cc:content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=qcppdkim1; bh= xrae0P7gUt75AhWHmiemIgjk6vnyOpZYcSvfCh7M7I8=; b=fZnNimaSKkGrjM+X Gnc4PGcLsrm8DHUPlSFUV0qwPyDXk7f6PPirnHgGqnfP2SD2x5YMkuRx7VIA9GBR OlkaSRO3lNHD0wNrCOBB4vFSs8IC7x+e7YGSy8nVmHJtCMRypxNJ6MEBMCap+5PR NDJtny7fF+sAf4Bv5Pqt2lv4Kb7QD4yByniRjC9nC7f/i80iWcMq8cz9YZ2MiQc+ np+J6/vHvu5RtO7/SGu2wC1IQu2ls6hTZV5CT40k7ULgU/VayzkZbikDnmYnCFZQ Gjfbz7+MgHAWaqdmMkjS+2ImOWlP8a7+VQzw656j/LBuMOeLS4lwV43l6jmaokdu RMk3fw== Received: from mail-pl1-f199.google.com (mail-pl1-f199.google.com [209.85.214.199]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 4c80drrq6s-1 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NOT) for ; Tue, 10 Feb 2026 11:10:05 +0000 (GMT) Received: by mail-pl1-f199.google.com with SMTP id d9443c01a7336-2a946c0e441so10003195ad.1 for ; Tue, 10 Feb 2026 03:10:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oss.qualcomm.com; s=google; t=1770721805; x=1771326605; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=xrae0P7gUt75AhWHmiemIgjk6vnyOpZYcSvfCh7M7I8=; b=ErPUtMJ2qA4dBW7m90KjQxuDHysqFEPca//ena1VwPCFiD5GR7k/LWl4GveibmOmqe VICV+pdLwBWONnjid9ZB+GYhWG3gV3DA81G3vtSA7U3dBuYafJ+eqQ9AJLv/TXv9pEhA tI5DTknLkuiTDS/sFCxD8Ee13H0RWEDGo1taxHPfms8yPe7anNI4UZSuDpCwxiB/ogL3 bbA6UUwiUMICVrYttYwsAyEsrgFwWCO+II1BcI3mB3ES+23iEn2OvI5R0dgMGiHWHDKf UlQOmcoStB5tEaueLxdOXh/BWl3KqDRII+RiLuM9V4ilshU4OrM8NdTKfFFlE4g45uFr 13yQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770721805; x=1771326605; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=xrae0P7gUt75AhWHmiemIgjk6vnyOpZYcSvfCh7M7I8=; b=Yvn+atiefrlOf52i928QF75WNMFsZhDP33ZUuQtUCPl1DwjD3tffv3alVythtXd2z3 8R3did2HuNbmzPki477MhDhLzDixjBTt4GEco/L1zL5LrgFGFVhYOQnutxvV7WuQl95t aftDM+ls7gxEM/giMeb5oU1Cz0Vdo1+mEkrtJ2y/Z4H8hdTmTVhgod423EJ1gOamwIGO 0GlVhN5McvOMarPjohygenu2DoUulxzkYqrKJGE0ardy6rG3G07kXC4gjOIs92jkCcmI JlchPwLyFRi6wPhW6eIU4DQjM2xC5RSLE3kNYIeLx5gRbLkdVl/LQiDANSU/Bf58Yt2S Do+w== X-Forwarded-Encrypted: i=1; AJvYcCXG//qzq+cIzYbWJSyhyiG+rRKL7O2GceUHFYSZZycyZWnG4miNEtEpk6TXrcD/uZpgMZkLacaZtiOJMV8=@vger.kernel.org X-Gm-Message-State: AOJu0YxK0zEFM8jA+VW8Efi38obX47EMBq9HVAkZyskOSen6rFjwu95d kZkmp124JufJ1JzZqvsOQViHVEEpvxVj9mdYQTAL/t1yU3TxaOz6ls64b7bkRRI7701QuL3OMtl BYONwFKtB8KLNvT3deLTGz0vXrv3tmGwq5ZshyRrE35jK7+mVuInX+21mi1j4Bt2lnp4= X-Gm-Gg: AZuq6aL5yEzfYFNojeP7Ef/9C+GtgjqBLRDQA3opisJLPyWT13ZaxdWXupULzEfLf80 TuOiHhOn6y/Hj/7WUi3jVKdrMi4whrYodGdCbKoxhLP/3JbL+SI/82WkI/tIPdeu3Xn/0tUwFwU Z/+d9hqIntEUvwZAnx2HnUJSCDS1z4r7KgcW+rB3oSsoT9wvMu/P1y+iCgW535gE7IXiHr4FrQl vnV6eTM9BCypi270hHLmxCG8IaasLAr6gRBHskSQiuL+3eddICHYZ9aZtZJH4zCLF2bOJ0rKS6G 3Y2hNM2Vfv5ZSOOFa+JvMRXkT1aEp18lHWF2ITGETqrfMuAGr1xeoCtJzM0Kcf8qGrqu7pWWHI/ AHFl5czGhe6ZFxgj+nRhavFIeevARPGW6lICsYY/FkcoOXpjubH3G X-Received: by 2002:a17:903:985:b0:2a9:cb10:42d with SMTP id d9443c01a7336-2a9cb100bcemr94582695ad.61.1770721802921; Tue, 10 Feb 2026 03:10:02 -0800 (PST) X-Received: by 2002:a17:903:985:b0:2a9:cb10:42d with SMTP id d9443c01a7336-2a9cb100bcemr94582105ad.61.1770721802081; Tue, 10 Feb 2026 03:10:02 -0800 (PST) Received: from [10.219.57.215] ([202.46.23.19]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2a95dce24f0sm119367945ad.32.2026.02.10.03.09.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 10 Feb 2026 03:10:01 -0800 (PST) Message-ID: <7720d215-9f92-4f0f-83af-c992e1cbe531@oss.qualcomm.com> Date: Tue, 10 Feb 2026 16:39:56 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] iommu/arm-smmu: Use pm_runtime in fault handlers To: Pranjal Shrivastava , Robin Murphy Cc: Will Deacon , Joerg Roedel , Rob Clark , Connor Abbott , linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, Akhil P Oommen , Pratyush Brahma References: <20260127-smmu-rpm-v1-1-2ef2f4c85305@oss.qualcomm.com> <9fb8f661-a235-4f86-bc10-f80a21a8fa9d@arm.com> <00fcbcf2-3f48-410d-88a3-88dc834c1ed7@oss.qualcomm.com> Content-Language: en-US From: Prakash Gupta In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMjEwMDA5MiBTYWx0ZWRfX9Ofj3zneBnYW 9IPEpMDN5HcA+M22veHiY17Cj76Yf1VwYKkMCnbzwyB4wCii+r8ZYK71B9PmgUT+ZElSB1DYo5R PohzCcVdpP2AAllSx4vn03za8/9fKbyoUMMFBCNoG6dreVZ0zzUZkhFaxtlq2DcXO6zyGucPhkx 78mSXMmupGOv9VE1/nVDPwRcBsLxJvVTf++lpguxgRIA4eUSRyg5rsNlKvmX/EDvnvasSNE06qz DK5dIAxGCIfhBcGXviEcnmvCKJd676QtVmAA2hXWrDt2VYLt5Flly1bj8s/5xZ9zOcWLJw41xnB G23ew3SjTNPVoemNi1RwON2B5Wkf5pdQaGU9+XB037xTn7K++CdN5+rCYMQomrEZFPkcDw8FnRi cxGRa8i4mL1VUu5ggNjbCbLY3z2de+rvRfTWkFE70Ubl1zGzmFNJnVCmld2RdemTNepItdN4O3E wPpjVtyE4wsl1Sc6U9w== X-Authority-Analysis: v=2.4 cv=fd+gCkQF c=1 sm=1 tr=0 ts=698b120d cx=c_pps a=JL+w9abYAAE89/QcEU+0QA==:117 a=j4ogTh8yFefVWWEFDRgCtg==:17 a=IkcTkHD0fZMA:10 a=HzLeVaNsDn8A:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=Mpw57Om8IfrbqaoTuvik:22 a=GgsMoib0sEa3-_RKJdDe:22 a=VwQbUJbxAAAA:8 a=1XWaLZrsAAAA:8 a=oqkVm95N0dxC-dYrnX4A:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=324X-CrmTo6CU4MGRt3R:22 X-Proofpoint-ORIG-GUID: e56xP9c1S3pXT8d0w9tyulcd9c8BHBTG X-Proofpoint-GUID: e56xP9c1S3pXT8d0w9tyulcd9c8BHBTG X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-02-10_01,2026-02-10_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 phishscore=0 priorityscore=1501 suspectscore=0 malwarescore=0 bulkscore=0 lowpriorityscore=0 spamscore=0 impostorscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2601150000 definitions=main-2602100092 On 2/3/2026 1:44 AM, Pranjal Shrivastava wrote: > On Wed, Jan 28, 2026 at 06:44:35PM +0000, Robin Murphy wrote: >> [ +Pranjal as this might matter for v3 too... ] >> > > Hi Robin, > > To weigh in from the arm-smmu-v3 side, we’ve attempted to address the > "can of worms" regarding power races by leaning on these differences: > > - Threaded IRQs for PRI/Events: In the recent series[1], the PRI and > event handlers are fully threaded. This allows us to call > arm_smmu_rpm_get() safely, as the handler can sleep while waiting for > the hardware to resume. > > - GERROR Handling: Since GERROR remains a hard IRQ, we handle any > pending gerrors in the suspend callback before the SMMU actually > powers down. Any GERROR interrupts received while the device was > suspended are treated as spurious and ignored. > > Thanks, > Praan [1] refer to case where SMMU state is not retained during smmu device power down, this I think is equally applicable for both context and global faults. Since the ARM SMMU runtime resume triggers a device reset, any pending faults would be cleared during resume. Here the solution can be to handle both global and context faults before allowing the SMMU device to suspend. With this approach, any hard or threaded IRQ scheduled after the SMMU device has suspended can be safely ignored. One concern I see is iommu fault reporting to clients while handling fault during smmu device suspend. Thanks, Prakash [1] https://lore.kernel.org/all/20260126151157.3418145-9-praan@google.com/