From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BEF7BC636CD for ; Fri, 10 Feb 2023 11:47:01 +0000 (UTC) Received: from localhost ([::1] helo=shelob.surriel.com) by shelob.surriel.com with esmtp (Exim 4.96) (envelope-from ) id 1pQRpy-0001KZ-35; Fri, 10 Feb 2023 06:45:06 -0500 Received: from mscreen.etri.re.kr ([129.254.9.16]) by shelob.surriel.com with esmtps (TLS1.2) tls TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA (Exim 4.96) (envelope-from ) id 1pQRpn-0000Ag-31 for kernelnewbies@kernelnewbies.org; Fri, 10 Feb 2023 06:45:01 -0500 Received: from unknown (HELO send001-relay.gov-dooray.com) (211.180.235.152) by 129.254.9.16 with ESMTP; 10 Feb 2023 20:44:17 +0900 X-Original-SENDERIP: 211.180.235.152 X-Original-MAILFROM: ckim@etri.re.kr X-Original-RCPTTO: kernelnewbies@kernelnewbies.org Received: from [10.162.225.106] (HELO smtp001-imp.gov-dooray.com) ([10.162.225.106]) by send001-relay.gov-dooray.com with SMTP id b1bbdc2d63e62e10; Fri, 10 Feb 2023 20:44:16 +0900 DKIM-Signature: a=rsa-sha256; b=nPZG+RZcI/pN/phDPEvdvImzK9nswgcZ8KX4p84M2m/otLhkLTPAsZKLFx22s7OyKZxE0fa9f1 1LHZObbQQEBKNtx0FiE6h7Sq13YivMmmtQzH5eFPawTegqhLLWqEdnhDmZ9xXv4BgoAaGpygJTtB nOlAFqZfpwGGdWQeUxIBc6V5I6CdwN6/DAIjUFscDVmeowGR1CNS1bXSLpkHLWjyn0SNTaeZGt32 I78Z4/XfhwPTwClHdiOSbYG3qi4umD4TafMWQ5x9iqGPSh4Q9ydYMZMgDCO5v9Qpnvh1TGCFLBs3 tIbQbojsj4I8ySSqiLdoVnfGSD8n32oj3vF27r0Q==; c=relaxed/relaxed; s=selector; d=dooray.com; v=1; bh=FRi9e2S3uNtffbg46KWzBD/G+7pIXQMT8jjj69FuosA=; h=From:To:Subject:Message-ID; Received: from [129.254.132.39] (HELO CHANKIMPC) ([129.254.132.39]) by smtp001-imp.gov-dooray.com with SMTP id 9162caa263e62e10; Fri, 10 Feb 2023 20:44:16 +0900 From: "Chan Kim" To: Subject: Use of "iommu-map-mask" for PCIe root complex device tree node, does it make actual requester ID ignored? Date: Fri, 10 Feb 2023 20:44:14 +0900 Message-ID: <07e301d93d45$0037e080$00a7a180$@etri.re.kr> MIME-Version: 1.0 X-Mailer: Microsoft Outlook 16.0 Content-Language: ko Thread-Index: Adk9RKa174tI5frHQjKfgGV3Mm2d6w== X-BeenThere: kernelnewbies@kernelnewbies.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Learn about the Linux kernel List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kernelnewbies-bounces@kernelnewbies.org Hello all, For pcie RC's iommu, (this iommu translates address for each PCI device dma masters when they access memory or io in the system), we can set "iommus" specifier in the device tree node for the PCIe RC. The "iommus" property generally tells for a bus master devices which iommu device's master interface it is connected to. (iommu device sits between the interconnect and the dma master device). For PCIe RC case, we can use RID(requester ID) from the PCIe device in the iommu processing so that the PCIe devices can use their own address translation table in the iommu. I briefly saw 'of_iommu_configure_dev_id' and 'of_map_id' functions and guessed even if the hardware connects the RID from the PCIe to the iommu device, if I set 'iommu-map-mask' value to zero, the software sets the iommu translation table so that the actual RID is not used in the processing. But I'm not sure if my guess is correct. Can any one tell me what the case is? Thank you. Chan Kim _______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies