From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.151]) (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 DD83B137D for ; Sat, 26 Aug 2023 08:03:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1693037036; x=1724573036; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=4WuaqgVS84ILp+nQYZ24EIA/OW8M4Tg/kexsQpfKmwQ=; b=fZ02nuhqNT6Q7966UoMZFAYWZLtVE0RdMFlzvZ6Sww6Sox5+NwrJg17J qy08vJcupCJ3MacL3gtDCYntDEJnxIRmV0WCPKQTTafXvWr2u9UM2pcG5 QEiKPjt+j2MnBRkFzBuRh2/OisBbT0mfaRJrWH+9jmwviZDREpGrwrzwV ASrz+oYEVTF61u2taBXgug22qR+DwgvXut/dgt7eyV+udc2b7zkFripmM FtX/O8asCmPwSvsRTDtzVTYv3qZ+qLvgZjs6HGBUI9jkIU2JbFGvt2dZ+ cGPZHQr/LVBcmx1VBTtEGCRUgLFrgyGMaC0HOmxXRZeA/GPukZ6rkRotO A==; X-IronPort-AV: E=McAfee;i="6600,9927,10813"; a="355190949" X-IronPort-AV: E=Sophos;i="6.02,203,1688454000"; d="scan'208";a="355190949" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Aug 2023 01:03:55 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10813"; a="767153317" X-IronPort-AV: E=Sophos;i="6.02,203,1688454000"; d="scan'208";a="767153317" Received: from allen-box.sh.intel.com (HELO [10.239.159.127]) ([10.239.159.127]) by orsmga008.jf.intel.com with ESMTP; 26 Aug 2023 01:03:52 -0700 Message-ID: Date: Sat, 26 Aug 2023 16:01:16 +0800 Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Cc: baolu.lu@linux.intel.com, "Liu, Yi L" , Jacob Pan , "iommu@lists.linux.dev" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v4 09/10] iommu: Make iommu_queue_iopf() more generic Content-Language: en-US To: "Tian, Kevin" , Joerg Roedel , Will Deacon , Robin Murphy , Jason Gunthorpe , Jean-Philippe Brucker , Nicolin Chen References: <20230825023026.132919-1-baolu.lu@linux.intel.com> <20230825023026.132919-10-baolu.lu@linux.intel.com> From: Baolu Lu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 8/25/23 4:17 PM, Tian, Kevin wrote: >> + >> /** >> * iopf_queue_flush_dev - Ensure that all queued faults have been >> processed >> * @dev: the endpoint whose faults need to be flushed. > Presumably we also need a flush callback per domain given now > the use of workqueue is optional then flush_workqueue() might > not be sufficient. > The iopf_queue_flush_dev() function flushes all pending faults from the IOMMU queue for a specific device. It has no means to flush fault queues out of iommu core. The iopf_queue_flush_dev() function is typically called when a domain is detaching from a PASID. Hence it's necessary to flush the pending faults from top to bottom. For example, iommufd should flush pending faults in its fault queues after detaching the domain from the pasid. The fault_param->lock mutex is sufficient to avoid the race condition if the workqueue is not used. However, if the workqueue is used, then it is possible for a workqueue thread to be in the middle of delivering a fault while the fault queue is being flushed. Best regards, baolu