From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 8B0C137EFF2 for ; Tue, 14 Apr 2026 21:14:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776201257; cv=none; b=Yo91XW8tMsilpeCPnPsMpUtzcGefDqAvY2q0PHAyvHqWBYCY+rfXrV55W332iun9orKE3BsIpsCTp/OUhwLISa9fduzH/fAsO034v9XItcC256aJKi7xIzw3LPb83iK8RcbpxLEIg0RiS5aWYIIZmvadke3ppfs/CqhnWwhZNmM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776201257; c=relaxed/simple; bh=Lhuq5xAlpwVPJn07YR/Cag2fu1WPE3u3MTdnXtAAdOY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=i/5c46/FOzHbNxVVr9KPMzwzwTFhNg6u2wu//ytV5Qb3kf41yxUlqKMO+mH9kLiHuCMjGoGF7CQljuBHPgEx/DqN82qs4oXlr8iawgBVCwjlI1/g1FhNxqhfmR+TOFVfdyWJhDWLhp+QzH/N9WiB7+yNIhd3/DS1B8+1qbiZVCk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=MlRp2nCR; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="MlRp2nCR" Received: from DESKTOP-0403QTC.corp.microsoft.com (unknown [20.191.74.188]) by linux.microsoft.com (Postfix) with ESMTPSA id CE4D120B6F08; Tue, 14 Apr 2026 14:14:14 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com CE4D120B6F08 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1776201255; bh=DueQqGsTeBZ5f9epBqPjmXrmVIT9Xztuh7ie4O7QWxY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MlRp2nCRMjo3p5MuVZNqNBiIb4zcwNBqx6YZY56JszJAra5mlEdnyczHLzhI7BwNr BYZZGQhx9ygYjAzNLC1MhyMmlHa0iJ0lKDJwsNhRLGoBgcmY5sm5MgnaOfhobRCnyh ISP19pgS8GAqHBKUh/GiG7T4441XWm2dbIe3Iiok= From: Jacob Pan To: linux-kernel@vger.kernel.org, "iommu@lists.linux.dev" , Jason Gunthorpe , Alex Williamson , Joerg Roedel , Mostafa Saleh , David Matlack , Robin Murphy , Nicolin Chen , "Tian, Kevin" , Yi Liu Cc: skhawaja@google.com, pasha.tatashin@soleen.com, Will Deacon , Jacob Pan , Baolu Lu Subject: [PATCH V4 01/10] iommufd: Support a HWPT without an iommu driver for noiommu Date: Tue, 14 Apr 2026 14:14:03 -0700 Message-Id: <20260414211412.2729-2-jacob.pan@linux.microsoft.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260414211412.2729-1-jacob.pan@linux.microsoft.com> References: <20260414211412.2729-1-jacob.pan@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Jason Gunthorpe Create just a little part of a real iommu driver, enough to slot in under the dev_iommu_ops() and allow iommufd to call domain_alloc_paging_flags() and fail everything else. This allows explicitly creating a HWPT under an IOAS. Signed-off-by: Jason Gunthorpe Signed-off-by: Jacob Pan --- v4: - Make iommufd_noiommu_ops const v3: - Add comment to explain the design difference over the legacy noiommu VFIO code. fix const hwpt --- drivers/iommu/iommufd/Makefile | 1 + drivers/iommu/iommufd/hw_pagetable.c | 11 ++- drivers/iommu/iommufd/hwpt_noiommu.c | 102 ++++++++++++++++++++++++ drivers/iommu/iommufd/iommufd_private.h | 2 + 4 files changed, 114 insertions(+), 2 deletions(-) create mode 100644 drivers/iommu/iommufd/hwpt_noiommu.c diff --git a/drivers/iommu/iommufd/Makefile b/drivers/iommu/iommufd/Makefile index 71d692c9a8f4..2b1a020b14a6 100644 --- a/drivers/iommu/iommufd/Makefile +++ b/drivers/iommu/iommufd/Makefile @@ -10,6 +10,7 @@ iommufd-y := \ vfio_compat.o \ viommu.o +iommufd-$(CONFIG_VFIO_NOIOMMU) += hwpt_noiommu.o iommufd-$(CONFIG_IOMMUFD_TEST) += selftest.o obj-$(CONFIG_IOMMUFD) += iommufd.o diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c index fe789c2dc0c9..37316d77277d 100644 --- a/drivers/iommu/iommufd/hw_pagetable.c +++ b/drivers/iommu/iommufd/hw_pagetable.c @@ -8,6 +8,13 @@ #include "../iommu-priv.h" #include "iommufd_private.h" +static const struct iommu_ops *get_iommu_ops(struct iommufd_device *idev) +{ + if (IS_ENABLED(CONFIG_VFIO_NOIOMMU) && !idev->igroup->group) + return &iommufd_noiommu_ops; + return dev_iommu_ops(idev->dev); +} + static void __iommufd_hwpt_destroy(struct iommufd_hw_pagetable *hwpt) { if (hwpt->domain) @@ -114,7 +121,7 @@ iommufd_hwpt_paging_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas, IOMMU_HWPT_ALLOC_DIRTY_TRACKING | IOMMU_HWPT_FAULT_ID_VALID | IOMMU_HWPT_ALLOC_PASID; - const struct iommu_ops *ops = dev_iommu_ops(idev->dev); + const struct iommu_ops *ops = get_iommu_ops(idev); struct iommufd_hwpt_paging *hwpt_paging; struct iommufd_hw_pagetable *hwpt; int rc; @@ -229,7 +236,7 @@ iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx, struct iommufd_device *idev, u32 flags, const struct iommu_user_data *user_data) { - const struct iommu_ops *ops = dev_iommu_ops(idev->dev); + const struct iommu_ops *ops = get_iommu_ops(idev); struct iommufd_hwpt_nested *hwpt_nested; struct iommufd_hw_pagetable *hwpt; int rc; diff --git a/drivers/iommu/iommufd/hwpt_noiommu.c b/drivers/iommu/iommufd/hwpt_noiommu.c new file mode 100644 index 000000000000..1c8cae02beec --- /dev/null +++ b/drivers/iommu/iommufd/hwpt_noiommu.c @@ -0,0 +1,102 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2021-2022, NVIDIA CORPORATION & AFFILIATES + */ +#include +#include +#include "iommufd_private.h" + +static const struct iommu_domain_ops noiommu_amdv1_ops; + +struct noiommu_domain { + union { + struct iommu_domain domain; + struct pt_iommu_amdv1 amdv1; + }; + spinlock_t lock; +}; +PT_IOMMU_CHECK_DOMAIN(struct noiommu_domain, amdv1.iommu, domain); + +static void noiommu_change_top(struct pt_iommu *iommu_table, + phys_addr_t top_paddr, unsigned int top_level) +{ +} + +static spinlock_t *noiommu_get_top_lock(struct pt_iommu *iommupt) +{ + struct noiommu_domain *domain = + container_of(iommupt, struct noiommu_domain, amdv1.iommu); + + return &domain->lock; +} + +static const struct pt_iommu_driver_ops noiommu_driver_ops = { + .get_top_lock = noiommu_get_top_lock, + .change_top = noiommu_change_top, +}; + +static struct iommu_domain * +noiommu_alloc_paging_flags(struct device *dev, u32 flags, + const struct iommu_user_data *user_data) +{ + struct pt_iommu_amdv1_cfg cfg = {}; + struct noiommu_domain *dom; + int rc; + + if (flags || user_data) + return ERR_PTR(-EOPNOTSUPP); + + cfg.common.hw_max_vasz_lg2 = 64; + cfg.common.hw_max_oasz_lg2 = 52; + cfg.starting_level = 2; + cfg.common.features = + (BIT(PT_FEAT_DYNAMIC_TOP) | BIT(PT_FEAT_AMDV1_ENCRYPT_TABLES) | + BIT(PT_FEAT_AMDV1_FORCE_COHERENCE)); + + dom = kzalloc(sizeof(*dom), GFP_KERNEL); + if (!dom) + return ERR_PTR(-ENOMEM); + + spin_lock_init(&dom->lock); + dom->amdv1.iommu.nid = NUMA_NO_NODE; + dom->amdv1.iommu.driver_ops = &noiommu_driver_ops; + dom->domain.ops = &noiommu_amdv1_ops; + + /* Use mock page table which is based on AMDV1 */ + rc = pt_iommu_amdv1_init(&dom->amdv1, &cfg, GFP_KERNEL); + if (rc) { + kfree(dom); + return ERR_PTR(rc); + } + + return &dom->domain; +} + +static void noiommu_domain_free(struct iommu_domain *iommu_domain) +{ + struct noiommu_domain *domain = + container_of(iommu_domain, struct noiommu_domain, domain); + + pt_iommu_deinit(&domain->amdv1.iommu); + kfree(domain); +} + +/* + * AMDV1 is used as a dummy page table for no-IOMMU mode, similar to the + * iommufd selftest mock page table. + * Unlike legacy VFIO no-IOMMU mode, where no container level APIs are + * supported, this allows IOAS and hwpt objects to exist without hardware + * IOMMU support. IOVAs are used only for IOVA-to-PA lookups not for + * hardware translation in DMA. + * + * This is only used with iommufd and cdev-based interfaces and does not + * apply to legacy VFIO group-container based noiommu mode. + */ +static const struct iommu_domain_ops noiommu_amdv1_ops = { + IOMMU_PT_DOMAIN_OPS(amdv1), + .free = noiommu_domain_free, +}; + +const struct iommu_ops iommufd_noiommu_ops = { + .domain_alloc_paging_flags = noiommu_alloc_paging_flags, +}; diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h index 6ac1965199e9..2682b5baa6e9 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -464,6 +464,8 @@ static inline void iommufd_hw_pagetable_put(struct iommufd_ctx *ictx, refcount_dec(&hwpt->obj.users); } +extern const struct iommu_ops iommufd_noiommu_ops; + struct iommufd_attach; struct iommufd_group { -- 2.34.1