From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.19]) (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 6F3E51CFA9 for ; Thu, 20 Jun 2024 06:27:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.19 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718864859; cv=none; b=jJay0fRsdgr4RVK6sJt1RiG3rJLq40a2dsu9G7gZwkEY/RjlSRN12pGwTQMXcU3g/8IsqN7MKt7HVEfTxkRHLE/Q5JhvIQ1AuLvCaTT8wnBHm3yctp4Cz2kOwtXIzmEG296YEyEcU0Qi/V1sD4LlN00sHWQDOwRwHGjLZu7uTug= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718864859; c=relaxed/simple; bh=4K30b5dp3sj+V+cw881bFFO4IS728f+ho2gPwsieBCs=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=JMJFi7KCY2M9oyADthf0DuM7Fx1xb+eraqI051wEcHL167y+hz56WsTtQBSGDCXBIB2cQ8XRYE+gdmWBFKRGLv9zc7DDXfNtRFy5qNxcYGmmM7oOoj7j4zsZEgDiD6MHobgFGCAeigyR1BKYgXUiRMHATDsCEyyMy3Ej7K4HPTA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=UhaKJdMV; arc=none smtp.client-ip=198.175.65.19 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="UhaKJdMV" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1718864858; x=1750400858; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=4K30b5dp3sj+V+cw881bFFO4IS728f+ho2gPwsieBCs=; b=UhaKJdMVmRg3vgLXJPg+LUPJw18i/sLBU7Bz94zee3VC6CZ21bWb7CUW Nj3lknqgveaTufZxcAein1bLg4hLk9A084v4JyXxUhkVxgPBJTLB5fymd f3NHh3iXNOjKSDNj/k2n1N+y/1EZha4GQCHIxNZtHhaE2RyohR07V6Qdx vEjFea6DWRKUjtahGUPEJO9RLwrN9K8Lb68jxmNtfLFfq2JprTkERajCD vJn3sIvxTWQrSHiJc37wVgmYJtt++WqfwL8OwZzPasORAvDcE1WIpK32W Ko8tepGiZH+jvmXpjE59djuJf7YsggAi1G+OvhvpiyaAx/cBCDCJq2uSF A==; X-CSE-ConnectionGUID: 5w4Fi9nzSBWTmoq0mWFXJQ== X-CSE-MsgGUID: RiSuUnrBR1yxV0CIDugcGA== X-IronPort-AV: E=McAfee;i="6700,10204,11108"; a="15652778" X-IronPort-AV: E=Sophos;i="6.08,251,1712646000"; d="scan'208";a="15652778" Received: from orviesa006.jf.intel.com ([10.64.159.146]) by orvoesa111.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Jun 2024 23:27:37 -0700 X-CSE-ConnectionGUID: nWcQuqGATX2PF1ovSj6dzA== X-CSE-MsgGUID: LVAjM0a4T6KPM0RxYaGT9Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,251,1712646000"; d="scan'208";a="42592334" Received: from blu2-mobl.ccr.corp.intel.com (HELO [10.124.229.145]) ([10.124.229.145]) by orviesa006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Jun 2024 23:27:35 -0700 Message-ID: <8c78f966-539c-4c81-92a6-32d32bb10e8b@linux.intel.com> Date: Thu, 20 Jun 2024 14:27:30 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: baolu.lu@linux.intel.com, Joerg Roedel , Will Deacon , Robin Murphy , Jacek Lawrynowicz , "iommu@lists.linux.dev" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 1/1] iommu/vt-d: Fix missed device TLB cache tag To: Vasant Hegde , "Tian, Kevin" , Jason Gunthorpe References: <20240619015345.182773-1-baolu.lu@linux.intel.com> <20240619164620.GN791043@ziepe.ca> <1dfb467d-f25a-4270-8a36-a048f061e2aa@linux.intel.com> <976d4054-6306-4325-a112-5cf69b0c6f34@linux.intel.com> Content-Language: en-US From: Baolu Lu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 2024/6/20 13:54, Vasant Hegde wrote: > On 6/20/2024 8:43 AM, Baolu Lu wrote: >> On 6/20/24 11:04 AM, Tian, Kevin wrote: >>>> From: Baolu Lu >>>> Sent: Thursday, June 20, 2024 8:50 AM >>>> >>>> On 6/20/24 12:46 AM, Jason Gunthorpe wrote: >>>>> On Wed, Jun 19, 2024 at 09:53:45AM +0800, Lu Baolu wrote: >>>>>> When a domain is attached to a device, the required cache tags are >>>>>> assigned to the domain so that the related caches could be flushed >>>>>> whenever it is needed. The device TLB cache tag is created selectively >>>>>> by checking the ats_enabled field of the device's iommu data. This >>>>>> creates an ordered dependency between attach and ATS enabling paths. >>>>>> >>>>>> The device TLB cache tag will not be created if device's ATS is enabled >>>>>> after the domain attachment. This causes some devices, for example >>>>>> intel_vpu, to malfunction. >>>>> What? How is this even possible? >>>>> >>>>> ATS is controlled exclusively by the iommu driver, how can it be >>>>> changed without the driver knowing?? >>>> Yes. ATS is currently controlled exclusively by the iommu driver. The >>>> intel iommu driver enables PCI/ATS on the probe path after the default >>>> domain is attached. That means when the default domain is attached to >>>> the device, the ats_supported is set, but ats_enabled is cleared. So the >>>> cache tag for the device TLB won't be created. >>> I don't quite get why this is specific to the probe path and the default >>> domain. >> The issue is with the domain attaching device path, not specific to the >> probe or default domain. >> >>> dmar_domain_attach_device() >>> { >>>     cache_tag_assign_domain(); >>>     //setup pasid entry for pt/1st/2nd >>>     iommu_enable_pci_caps(); >>> } >>> >>> seems that for all domain attaches above is coded in a wrong order >>> as ats is enabled after the cache tag is assigned. >> Yes, exactly. But simply changing the order isn't future-proof, >> considering ATS control will eventually be moved out of iommu drivers. > [Unrelated to this patch] > > You mean ATS setup will be moved to individual device driver? Is there any > reason for that? Not exactly to individual device drivers, but it should be out of the iommu drivers. https://lore.kernel.org/linux-iommu/BL1PR12MB51441FC4303BD0442EDB7A9CF7FFA@BL1PR12MB5144.namprd12.prod.outlook.com/ Best regards, baolu