From nobody Sat Feb 7 17:13:56 2026 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 63EDFC77B7A for ; Wed, 7 Jun 2023 03:55:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240921AbjFGDyw (ORCPT ); Tue, 6 Jun 2023 23:54:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34950 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240891AbjFGDxt (ORCPT ); Tue, 6 Jun 2023 23:53:49 -0400 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 874711BC6; Tue, 6 Jun 2023 20:53:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1686110008; x=1717646008; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=6WUAvVJQ7l32wEzpvJFBaKCQ/VSQzTnT+W3JYlZ1JaI=; b=iXVLB7UAGvqFDEx9Y0Y3zMrfxGgav3xoz3yaykrc0hc/sdzesmEImGAM 5iyWDwCe6qXqbPRGjbfXVZIrwR5vxozmDDGbWcloU+/Omp4JkjcTwVx7Y y4gXtckHygG69L+ck0BNja2rS+00kCNvYuyvO8IGXWQH5FE7GHicU1JmM pUutzVpMkLG4Jj1BHIQbpnvQ37Dzf8XfrM9OpRzrXUX5o0JjX0VDTypFY 7hGOq5uhGz5ui0BZ9QmVSeEYMVdMTUvTwdjT4UYYxW41hUknyT2jB+XMg /sUilHT8EJb4JpLlPj2C8WuX4wc/NFvtdoWuAyyCzZt9X1DLuW9K8IObB A==; X-IronPort-AV: E=McAfee;i="6600,9927,10733"; a="385186343" X-IronPort-AV: E=Sophos;i="6.00,222,1681196400"; d="scan'208";a="385186343" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Jun 2023 20:53:28 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10733"; a="799125354" X-IronPort-AV: E=Sophos;i="6.00,222,1681196400"; d="scan'208";a="799125354" Received: from allen-box.sh.intel.com ([10.239.159.127]) by FMSMGA003.fm.intel.com with ESMTP; 06 Jun 2023 20:53:25 -0700 From: Lu Baolu To: Jason Gunthorpe , Kevin Tian , Joerg Roedel , Will Deacon , Robin Murphy , Alex Williamson , Nicolin Chen Cc: iommu@lists.linux.dev, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Lu Baolu , Jason Gunthorpe Subject: [PATCH 1/2] iommu: Prevent RESV_DIRECT devices from blocking domains Date: Wed, 7 Jun 2023 11:51:44 +0800 Message-Id: <20230607035145.343698-2-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230607035145.343698-1-baolu.lu@linux.intel.com> References: <20230607035145.343698-1-baolu.lu@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The IOMMU_RESV_DIRECT flag indicates that a memory region must be mapped 1:1 at all times. This means that the region must always be accessible to the device, even if the device is attached to a blocking domain. This is equal to saying that IOMMU_RESV_DIRECT flag prevents devices from being attached to blocking domains. This also implies that devices that implement RESV_DIRECT regions will be prevented from being assigned to user space since taking the DMA ownership immediately switches to a blocking domain. The rule of preventing devices with the IOMMU_RESV_DIRECT regions from being assigned to user space has existed in the Intel IOMMU driver for a long time. Now, this rule is being lifted up to a general core rule, as other architectures like AMD and ARM also have RMRR-like reserved regions. This has been discussed in the community mailing list and refer to below link for more details. Other places using unmanaged domains for kernel DMA must follow the iommu_get_resv_regions() and setup IOMMU_RESV_DIRECT - we do not restrict them in the core code. Cc: Robin Murphy Cc: Alex Williamson Cc: Kevin Tian Signed-off-by: Jason Gunthorpe Link: https://lore.kernel.org/linux-iommu/BN9PR11MB5276E84229B5BD952D78E959= 8C639@BN9PR11MB5276.namprd11.prod.outlook.com Signed-off-by: Lu Baolu --- include/linux/iommu.h | 2 ++ drivers/iommu/iommu.c | 39 +++++++++++++++++++++++++++++---------- 2 files changed, 31 insertions(+), 10 deletions(-) diff --git a/include/linux/iommu.h b/include/linux/iommu.h index d31642596675..fd18019ac951 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -409,6 +409,7 @@ struct iommu_fault_param { * @priv: IOMMU Driver private data * @max_pasids: number of PASIDs this device can consume * @attach_deferred: the dma domain attachment is deferred + * @requires_direct: The driver requested IOMMU_RESV_DIRECT * * TODO: migrate other per device data pointers under iommu_dev_data, e.g. * struct iommu_group *iommu_group; @@ -422,6 +423,7 @@ struct dev_iommu { void *priv; u32 max_pasids; u32 attach_deferred:1; + u32 requires_direct:1; }; =20 int iommu_device_register(struct iommu_device *iommu, diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 9e0228ef612b..e59de7852067 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -959,12 +959,7 @@ static int iommu_create_device_direct_mappings(struct = iommu_domain *domain, unsigned long pg_size; int ret =3D 0; =20 - if (!iommu_is_dma_domain(domain)) - return 0; - - BUG_ON(!domain->pgsize_bitmap); - - pg_size =3D 1UL << __ffs(domain->pgsize_bitmap); + pg_size =3D domain->pgsize_bitmap ? 1UL << __ffs(domain->pgsize_bitmap) := 0; INIT_LIST_HEAD(&mappings); =20 iommu_get_resv_regions(dev, &mappings); @@ -974,13 +969,22 @@ static int iommu_create_device_direct_mappings(struct= iommu_domain *domain, dma_addr_t start, end, addr; size_t map_size =3D 0; =20 + if (entry->type =3D=3D IOMMU_RESV_DIRECT) + dev->iommu->requires_direct =3D 1; + + if ((entry->type !=3D IOMMU_RESV_DIRECT && + entry->type !=3D IOMMU_RESV_DIRECT_RELAXABLE) || + !iommu_is_dma_domain(domain)) + continue; + + if (WARN_ON_ONCE(!pg_size)) { + ret =3D -EINVAL; + goto out; + } + start =3D ALIGN(entry->start, pg_size); end =3D ALIGN(entry->start + entry->length, pg_size); =20 - if (entry->type !=3D IOMMU_RESV_DIRECT && - entry->type !=3D IOMMU_RESV_DIRECT_RELAXABLE) - continue; - for (addr =3D start; addr <=3D end; addr +=3D pg_size) { phys_addr_t phys_addr; =20 @@ -2121,6 +2125,21 @@ static int __iommu_device_set_domain(struct iommu_gr= oup *group, { int ret; =20 + /* + * If the driver has requested IOMMU_RESV_DIRECT then we cannot allow + * the blocking domain to be attached as it does not contain the + * required 1:1 mapping. This test effectively exclusive the device from + * being used with iommu_group_claim_dma_owner() which will block vfio + * and iommufd as well. + */ + if (dev->iommu->requires_direct && + (new_domain->type =3D=3D IOMMU_DOMAIN_BLOCKED || + new_domain =3D=3D group->blocking_domain)) { + dev_warn(dev, + "Firmware has requested this device have a 1:1 IOMMU mapping, rejectin= g configuring the device without a 1:1 mapping. Contact your platform vendo= r.\n"); + return -EINVAL; + } + if (dev->iommu->attach_deferred) { if (new_domain =3D=3D group->default_domain) return 0; --=20 2.34.1 From nobody Sat Feb 7 17:13:56 2026 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 2F145C7EE23 for ; Wed, 7 Jun 2023 03:55:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240779AbjFGDzf (ORCPT ); Tue, 6 Jun 2023 23:55:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34576 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240873AbjFGDxu (ORCPT ); Tue, 6 Jun 2023 23:53:50 -0400 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A199619BA; Tue, 6 Jun 2023 20:53:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1686110011; x=1717646011; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=2oi385LpKq1ZlutXYkuJeGeLsStTSAV0zDtArWRKxVY=; b=jxfucnoRA/igVBPR7jw/5756qnPELVsXdqeTb0uL0dTlGWAtXcOz3iZA OhtioQQHPMaHRWGGIgPIqBNTUYuVKS/Mi3SG23JTcl+WRj20oAohQ4cWt x6DlFwlU8X3xXiHx599Q0IQ2fGGgnYOo74uLI5dJqHyuPHO49J4TCMMZm wBPadY0MkKeN5fpCNeP+JBk2SaTnc61uqjnhxTkAzdP9Ekq0oKiBgiA3L 9EvdyIqS6B50imPp/UBdky30yQ11SeZ3Y+aaJ7ef3GgxTUgFLlIZ1NsFE mCwE4Vm0OUHR6W9pKOmz6EoCCsg7rK65qpM/ernAJ8FUTMyB4c49oY8+3 Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10733"; a="385186356" X-IronPort-AV: E=Sophos;i="6.00,222,1681196400"; d="scan'208";a="385186356" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Jun 2023 20:53:31 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10733"; a="799125371" X-IronPort-AV: E=Sophos;i="6.00,222,1681196400"; d="scan'208";a="799125371" Received: from allen-box.sh.intel.com ([10.239.159.127]) by FMSMGA003.fm.intel.com with ESMTP; 06 Jun 2023 20:53:28 -0700 From: Lu Baolu To: Jason Gunthorpe , Kevin Tian , Joerg Roedel , Will Deacon , Robin Murphy , Alex Williamson , Nicolin Chen Cc: iommu@lists.linux.dev, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Lu Baolu Subject: [PATCH 2/2] iommu/vt-d: Remove rmrr check in domain attaching device path Date: Wed, 7 Jun 2023 11:51:45 +0800 Message-Id: <20230607035145.343698-3-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230607035145.343698-1-baolu.lu@linux.intel.com> References: <20230607035145.343698-1-baolu.lu@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The core code now prevents devices with RMRR regions from being assigned to user space. There is no need to check for this condition in individual drivers. Remove it to avoid duplicate code. Signed-off-by: Lu Baolu Reviewed-by: Jason Gunthorpe --- drivers/iommu/intel/iommu.c | 58 ------------------------------------- 1 file changed, 58 deletions(-) diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 8096273b034c..4efc87e74455 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -2458,30 +2458,6 @@ static int dmar_domain_attach_device(struct dmar_dom= ain *domain, return 0; } =20 -static bool device_has_rmrr(struct device *dev) -{ - struct dmar_rmrr_unit *rmrr; - struct device *tmp; - int i; - - rcu_read_lock(); - for_each_rmrr_units(rmrr) { - /* - * Return TRUE if this RMRR contains the device that - * is passed in. - */ - for_each_active_dev_scope(rmrr->devices, - rmrr->devices_cnt, i, tmp) - if (tmp =3D=3D dev || - is_downstream_to_pci_bridge(dev, tmp)) { - rcu_read_unlock(); - return true; - } - } - rcu_read_unlock(); - return false; -} - /** * device_rmrr_is_relaxable - Test whether the RMRR of this device * is relaxable (ie. is allowed to be not enforced under some conditions) @@ -2511,34 +2487,6 @@ static bool device_rmrr_is_relaxable(struct device *= dev) return false; } =20 -/* - * There are a couple cases where we need to restrict the functionality of - * devices associated with RMRRs. The first is when evaluating a device f= or - * identity mapping because problems exist when devices are moved in and o= ut - * of domains and their respective RMRR information is lost. This means t= hat - * a device with associated RMRRs will never be in a "passthrough" domain. - * The second is use of the device through the IOMMU API. This interface - * expects to have full control of the IOVA space for the device. We cann= ot - * satisfy both the requirement that RMRR access is maintained and have an - * unencumbered IOVA space. We also have no ability to quiesce the device= 's - * use of the RMRR space or even inform the IOMMU API user of the restrict= ion. - * We therefore prevent devices associated with an RMRR from participating= in - * the IOMMU API, which eliminates them from device assignment. - * - * In both cases, devices which have relaxable RMRRs are not concerned by = this - * restriction. See device_rmrr_is_relaxable comment. - */ -static bool device_is_rmrr_locked(struct device *dev) -{ - if (!device_has_rmrr(dev)) - return false; - - if (device_rmrr_is_relaxable(dev)) - return false; - - return true; -} - /* * Return the required default domain type for a specific device. * @@ -4146,12 +4094,6 @@ static int intel_iommu_attach_device(struct iommu_do= main *domain, struct device_domain_info *info =3D dev_iommu_priv_get(dev); int ret; =20 - if (domain->type =3D=3D IOMMU_DOMAIN_UNMANAGED && - device_is_rmrr_locked(dev)) { - dev_warn(dev, "Device is ineligible for IOMMU domain attach due to platf= orm RMRR requirement. Contact your platform vendor.\n"); - return -EPERM; - } - if (info->domain) device_block_translation(dev); =20 --=20 2.34.1