From patchwork Tue Mar 8 05:44:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baolu Lu X-Patchwork-Id: 12772967 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 456ADC433FE for ; Tue, 8 Mar 2022 05:46:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343926AbiCHFrr (ORCPT ); Tue, 8 Mar 2022 00:47:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343788AbiCHFrp (ORCPT ); Tue, 8 Mar 2022 00:47:45 -0500 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3EDE73BBF7; Mon, 7 Mar 2022 21:46:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1646718409; x=1678254409; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=FFVFu1/gLNtyq5Heu6S1wXB406UqdvSLzskp+SBaVXQ=; b=PEavtUqrb176/V+Rf2x0g8PiWuKoszYoDciwJ2iYpT5lHAW4cQPn+u+I hFmP0kfL4B+tuQCAHT2qZNJ81fq9dZe0YkEG6CI753/iLTkxeuAl4sYns JeqOY5JT6DXpj+EMgQ0q1GfO5Icmy89Ntim8/HtLgk4P2yITdaNuGD1BI bbp4IkAjE9/JgrBETTh7Wlb8HFprzfTC76PMQQJgQvobLzGciSvJ49lBA +OZ56pRid2o/EX1dyHZjD5vvMRGoSppj27HB+I956rlYi8aTVsYaMy1aU mXOtCRmE6PrVUK7Oht0mjKhb1Z3+ciBmZ9No5jw0PJy7RU8Z7tTk3PSgu g==; X-IronPort-AV: E=McAfee;i="6200,9189,10279"; a="234553173" X-IronPort-AV: E=Sophos;i="5.90,163,1643702400"; d="scan'208";a="234553173" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Mar 2022 21:46:48 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.90,163,1643702400"; d="scan'208";a="537430218" Received: from allen-box.sh.intel.com ([10.239.159.48]) by orsmga007.jf.intel.com with ESMTP; 07 Mar 2022 21:46:42 -0800 From: Lu Baolu To: Greg Kroah-Hartman , Joerg Roedel , Alex Williamson , Bjorn Helgaas , Jason Gunthorpe , Christoph Hellwig , Kevin Tian , Ashok Raj Cc: Will Deacon , Robin Murphy , Dan Williams , rafael@kernel.org, Diana Craciun , Cornelia Huck , Eric Auger , Liu Yi L , Jacob jun Pan , Chaitanya Kulkarni , Stuart Yoder , Laurentiu Tudor , Thierry Reding , David Airlie , Daniel Vetter , Jonathan Hunter , Li Yang , Dmitry Osipenko , iommu@lists.linux-foundation.org, linux-pci@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Lu Baolu Subject: [PATCH v8 06/11] PCI: portdrv: Set driver_managed_dma Date: Tue, 8 Mar 2022 13:44:16 +0800 Message-Id: <20220308054421.847385-7-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220308054421.847385-1-baolu.lu@linux.intel.com> References: <20220308054421.847385-1-baolu.lu@linux.intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org If a switch lacks ACS P2P Request Redirect, a device below the switch can bypass the IOMMU and DMA directly to other devices below the switch, so all the downstream devices must be in the same IOMMU group as the switch itself. The existing VFIO framework allows the portdrv driver to be bound to the bridge while its downstream devices are assigned to user space. The pci_dma_configure() marks the IOMMU group as containing only devices with kernel drivers that manage DMA. Avoid this default behavior for the portdrv driver in order for compatibility with the current VFIO usage. We achieve this by setting ".driver_managed_dma = true" in pci_driver structure. It is safe because the portdrv driver meets below criteria: - This driver doesn't use DMA, as you can't find any related calls like pci_set_master() or any kernel DMA API (dma_map_*() and etc.). - It doesn't use MMIO as you can't find ioremap() or similar calls. It's tolerant to userspace possibly also touching the same MMIO registers via P2P DMA access. Suggested-by: Jason Gunthorpe Suggested-by: Kevin Tian Signed-off-by: Lu Baolu Reviewed-by: Jason Gunthorpe Acked-by: Bjorn Helgaas --- drivers/pci/pcie/portdrv_pci.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c index 35eca6277a96..6b2adb678c21 100644 --- a/drivers/pci/pcie/portdrv_pci.c +++ b/drivers/pci/pcie/portdrv_pci.c @@ -202,6 +202,8 @@ static struct pci_driver pcie_portdriver = { .err_handler = &pcie_portdrv_err_handler, + .driver_managed_dma = true, + .driver.pm = PCIE_PORTDRV_PM_OPS, };