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 2463E1991DD; Thu, 2 Jan 2025 10:40:01 +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=1735814403; cv=none; b=uWWLojrzwvjMZ1k3bMoHMZhrqAhSlgSk4h+zqra0bqEtx1Uf0T8BEcXbStsnO/IsFMVBTh8sGlYBnRpZxRDBIbF53dDyaWqgD1w3EPHT4VybDr2n7HhLsG3xAf9paLpRHmIdtgQUxzYDzZ9iuMgwojGJjsSW95tkU+ElIkcM3tQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735814403; c=relaxed/simple; bh=sFhpSocXBzuHfvdIdwZUjNa+fLLP39W1xozKavWKN7k=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=L1YG9AvH23tqNn9H/7gR1+kyIUMUP9z65vZqjBBV+NOMnrKfGr5Dsh5/s+QEtFcBTpg33eZRqfXtGxT5kWwbCME3pdyDAH8x+7GgZZxkUfmpVPjRDl3MJEXdf5Rg2MQnic6573QmV/jU8cxUbTaA05pY0hRqGNj7xdaXDFhP2RY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=quicinc.com; spf=pass smtp.mailfrom=quicinc.com; dkim=pass (2048-bit key) header.d=quicinc.com header.i=@quicinc.com header.b=M+RCemqK; arc=none smtp.client-ip=205.220.168.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=quicinc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=quicinc.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=quicinc.com header.i=@quicinc.com header.b="M+RCemqK" Received: from pps.filterd (m0279867.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 502Abf7L014673; Thu, 2 Jan 2025 10:39:53 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h= cc:content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=qcppdkim1; bh= v3hq5pPhoLWrZ9X7JvsBOciwezW02shNULfJ/tgcfJM=; b=M+RCemqKUXimv01Y ZnDtEChLTQuXxUe8HeYi8HKdIWkKChuxSNmvlgtnscJqmgfNEw7Gj4LgdtL0JlAr 9qeZElMA9rN1ac/ibBWL3XBJfYZXsnfAIfMcQhp9HX8VYQZK1J3IIAfW895bj+Jx rW8nxAl8z9LNF5TxIFTLkWQWDW0Yfw9c3RUclWvOyKUkqlBcracUJhQie2VyaETU v2N0X87+YgyJszkuSVy/PDh13FOdYEiVhz8iIHtCkqRcxierDt/6Bw2Jq9rRe2Bi mk8Y1SQujavG6kjsTJW9WYwyxiV+yAREBc94/diDWhZ80plhPoXLikSKZd9UnZvV N+r+bw== Received: from nalasppmta03.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 43ws7a803n-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 02 Jan 2025 10:39:53 +0000 (GMT) Received: from nalasex01a.na.qualcomm.com (nalasex01a.na.qualcomm.com [10.47.209.196]) by NALASPPMTA03.qualcomm.com (8.18.1.2/8.18.1.2) with ESMTPS id 502Adq9S012910 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 2 Jan 2025 10:39:52 GMT Received: from [10.216.11.228] (10.80.80.8) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.9; Thu, 2 Jan 2025 02:39:50 -0800 Message-ID: <91d15d11-ec53-4ca2-a385-9fa69d861f2c@quicinc.com> Date: Thu, 2 Jan 2025 16:09:46 +0530 Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC] iommu: fix wrong DMA ops for iommu device To: , , , CC: , References: <20241213150415.653821-1-quic_charante@quicinc.com> Content-Language: en-US From: Charan Teja Kalla In-Reply-To: <20241213150415.653821-1-quic_charante@quicinc.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: nasanex01a.na.qualcomm.com (10.52.223.231) To nalasex01a.na.qualcomm.com (10.47.209.196) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: 6z0ZUrSPuaCUksmZqwBA8FiOfZsr_W5Z X-Proofpoint-GUID: 6z0ZUrSPuaCUksmZqwBA8FiOfZsr_W5Z X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.60.29 definitions=2024-09-06_09,2024-09-06_01,2024-09-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 lowpriorityscore=0 suspectscore=0 bulkscore=0 adultscore=0 spamscore=0 impostorscore=0 phishscore=0 clxscore=1015 malwarescore=0 mlxlogscore=999 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2411120000 definitions=main-2501020092 Just a quick ask if you have any comments for the below. BTW, in internal tests, when we revert the commit f188056352bc ("iommu: Avoid locking/unlocking for iommu_probe_device()", it is helping. I can share more details If the below is not sufficient. Thanks in advance... On 12/13/2024 8:34 PM, Charan Teja Kalla wrote: > Race between smmu device probe and iommu device probe is resulting into > wrong DMA ops used for the device. > > bus_iommu_probe(P1) of_iommu_configure(P2) > (from iommu_device_register) (from insmod of a driver) > -------------------------- -------------------------- > 1) probe_iommu_group() > (Fills just dev->iommu_group > under iommu_probe_device_lock) > 2) iommu_probe_device(): > (acquires the iommu_probe_device_lock, > but since dev->iommu_group is already > set, it just returns without > allocating the domain.) > > 3) of_dma_configure_id()-> > arch_setup_dma_ops() gets called for > this device, but returns with the > error message: > "Failed to set up IOMMU for device; > retaining platform DMA ops" > > 4) device probe is succeeded where it > can now setup iommu mappings using > wrong ->dma_ops > > 5) domain will be allocated later > and fills iommu_group->domain. > > Step 3) and 4) denies iommu device from using 'iommu_dma_ops'. > > This issue does exists on 6.6 because of commit f188056352bc ("iommu: > Avoid locking/unlocking for iommu_probe_device()") without which 2) > returns only after filling the domain under group->mutex, thus no issue. > > With commit b5c58b2fdc42("dma-mapping: direct calls for dma-iommu"), > ->iommu_dma_ops is removed altogether and iommu api are directly being > called under "use_dma_iommu(): return dev->dma_iommu". Again, > ->dma_iommu flag is set only after domain allocation. So, If > there is a sufficient delay between steps 4) and 5), issue is still > exists but that seems very narrow to me. > > I am thinking, setup of the domain before returning from step2) is the > way to fix this issue. Can you please help if you have any suggestions? > > Signed-off-by: Charan Teja Kalla > --- > drivers/iommu/iommu.c | 26 +++++++++++++++++++++++++- > 1 file changed, 25 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 3f1029c0825e..61fc8145f378 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -561,19 +561,43 @@ static int __iommu_probe_device(struct device *dev, struct list_head *group_list > int iommu_probe_device(struct device *dev) > { > const struct iommu_ops *ops; > + struct iommu_group *group; > int ret; > > mutex_lock(&iommu_probe_device_lock); > ret = __iommu_probe_device(dev, NULL); > mutex_unlock(&iommu_probe_device_lock); > if (ret) > - return ret; > + goto err_out; > + > + group = iommu_group_get(dev); > + if (!group) { > + ret = -ENODEV; > + goto err_release; > + } > + > + mutex_lock(&group->mutex); > + if (!group->default_domain) { > + ret = iommu_setup_default_domain(group, 0); > + if (ret) > + goto err_unlock; > + } > + mutex_unlock(&group->mutex); > + iommu_group_put(group); > > ops = dev_iommu_ops(dev); > if (ops->probe_finalize) > ops->probe_finalize(dev); > > return 0; > + > +err_unlock: > + mutex_unlock(&group->mutex); > + iommu_group_put(group); > +err_release: > + iommu_release_device(dev); > +err_out: > + return ret; > } > > static void __iommu_group_free_device(struct iommu_group *group,