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 08F9E35AC17 for ; Fri, 3 Apr 2026 05:11:59 +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=1775193120; cv=none; b=TY8nq188w5WEvKre0n6XtzpmNnhkrpmMzjfqiGu6C55/Upji5apamcX3FvHFRHlJ06vI3tsCrNz5XQPa+zMmkN1cZMhN6DyE1pUR3bbnGdNfth8zmrHeCWsryJjsR6eMbes8RV7avrG/kXevqsi3oPuVe3GJlTOPQxkLW0N3FyQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775193120; c=relaxed/simple; bh=N92SRpP+YB5otcSSkGz7rxxDOPKyMJ0M7ABS40aEhwE=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=BHoZgGn5a9Atde42H50VxcJ0m4JTzLD+2y+nPoSnLX59HCgDG8ZX8lo0gu/eNpMYcJAYgOsqlyFE79q6CnQXTjdviAUc6f/F4dX05EltetIVWn+gXrX0932XVKP6m6BQKkbmiSNbR/lpJSYcXpB7uci2HbnaF1GYCceIMCtJKok= 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=mNRq89WI; 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="mNRq89WI" Received: from DESKTOP-0403QTC.corp.microsoft.com (unknown [52.148.171.5]) by linux.microsoft.com (Postfix) with ESMTPSA id B8DA520B7136; Thu, 2 Apr 2026 22:11:51 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com B8DA520B7136 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1775193112; bh=GZ0UyWx9W5HBDqnNPhA1OWvphFbU0yyvmlcztWY2uGw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mNRq89WIpqpeEcNXvgf0CDczsUR7+SpA9xf3KEDVDORKclOVJViLY9ANzlHMeD0Tv aOU6gW8VtCOzVieosMQbQvmBWeRzTezlemEJd3FOnMp7qXMa583NB8c899W1svX+1H UcPjSj7fGeNmMe0Ycl7WAiWCtCzbccUP7xtSd9xM= 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 V3 03/10] iommufd: Allow binding to a noiommu device Date: Thu, 2 Apr 2026 22:11:39 -0700 Message-Id: <20260403051146.10210-4-jacob.pan@linux.microsoft.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260403051146.10210-1-jacob.pan@linux.microsoft.com> References: <20260403051146.10210-1-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 Allow iommufd to bind devices without an IOMMU (noiommu mode) by creating a dummy IOMMU group for such devices and skipping hwpt operations. This enables noiommu devices to operate through the same iommufd API as IOMMU- capable devices. Signed-off-by: Jason Gunthorpe Signed-off-by: Jacob Pan --- v3: - handle new error cases iommufd_device_bind. (Mostafa) --- drivers/iommu/iommufd/device.c | 126 +++++++++++++++++++++++---------- 1 file changed, 87 insertions(+), 39 deletions(-) diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c index 2f30ea069f66..215fd9660be3 100644 --- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -23,6 +23,11 @@ struct iommufd_attach { struct xarray device_array; }; +static bool is_vfio_noiommu(struct iommufd_device *idev) +{ + return !device_iommu_mapped(idev->dev) || !idev->dev->iommu; +} + static void iommufd_group_release(struct kref *kref) { struct iommufd_group *igroup = @@ -30,9 +35,11 @@ static void iommufd_group_release(struct kref *kref) WARN_ON(!xa_empty(&igroup->pasid_attach)); - xa_cmpxchg(&igroup->ictx->groups, iommu_group_id(igroup->group), igroup, - NULL, GFP_KERNEL); - iommu_group_put(igroup->group); + if (igroup->group) { + xa_cmpxchg(&igroup->ictx->groups, iommu_group_id(igroup->group), + igroup, NULL, GFP_KERNEL); + iommu_group_put(igroup->group); + } mutex_destroy(&igroup->lock); kfree(igroup); } @@ -204,32 +211,17 @@ void iommufd_device_destroy(struct iommufd_object *obj) struct iommufd_device *idev = container_of(obj, struct iommufd_device, obj); - iommu_device_release_dma_owner(idev->dev); + if (!is_vfio_noiommu(idev)) + iommu_device_release_dma_owner(idev->dev); iommufd_put_group(idev->igroup); if (!iommufd_selftest_is_mock_dev(idev->dev)) iommufd_ctx_put(idev->ictx); } -/** - * iommufd_device_bind - Bind a physical device to an iommu fd - * @ictx: iommufd file descriptor - * @dev: Pointer to a physical device struct - * @id: Output ID number to return to userspace for this device - * - * A successful bind establishes an ownership over the device and returns - * struct iommufd_device pointer, otherwise returns error pointer. - * - * A driver using this API must set driver_managed_dma and must not touch - * the device until this routine succeeds and establishes ownership. - * - * Binding a PCI device places the entire RID under iommufd control. - * - * The caller must undo this with iommufd_device_unbind() - */ -struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx, - struct device *dev, u32 *id) +static int iommufd_bind_iommu(struct iommufd_device *idev) { - struct iommufd_device *idev; + struct iommufd_ctx *ictx = idev->ictx; + struct device *dev = idev->dev; struct iommufd_group *igroup; int rc; @@ -238,11 +230,11 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx, * to restore cache coherency. */ if (!device_iommu_capable(dev, IOMMU_CAP_CACHE_COHERENCY)) - return ERR_PTR(-EINVAL); + return -EINVAL; - igroup = iommufd_get_group(ictx, dev); + igroup = iommufd_get_group(idev->ictx, dev); if (IS_ERR(igroup)) - return ERR_CAST(igroup); + return PTR_ERR(igroup); /* * For historical compat with VFIO the insecure interrupt path is @@ -268,21 +260,69 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx, if (rc) goto out_group_put; + /* igroup refcount moves into iommufd_device */ + idev->igroup = igroup; + return 0; + +out_group_put: + iommufd_put_group(igroup); + return rc; +} + +/** + * iommufd_device_bind - Bind a physical device to an iommu fd + * @ictx: iommufd file descriptor + * @dev: Pointer to a physical device struct + * @id: Output ID number to return to userspace for this device + * + * A successful bind establishes an ownership over the device and returns + * struct iommufd_device pointer, otherwise returns error pointer. + * + * A driver using this API must set driver_managed_dma and must not touch + * the device until this routine succeeds and establishes ownership. + * + * Binding a PCI device places the entire RID under iommufd control. + * + * The caller must undo this with iommufd_device_unbind() + */ +struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx, + struct device *dev, u32 *id) +{ + struct iommufd_device *idev; + int rc; + idev = iommufd_object_alloc(ictx, idev, IOMMUFD_OBJ_DEVICE); - if (IS_ERR(idev)) { - rc = PTR_ERR(idev); - goto out_release_owner; - } + if (IS_ERR(idev)) + return idev; + idev->ictx = ictx; - if (!iommufd_selftest_is_mock_dev(dev)) - iommufd_ctx_get(ictx); idev->dev = dev; idev->enforce_cache_coherency = device_iommu_capable(dev, IOMMU_CAP_ENFORCE_CACHE_COHERENCY); + + if (!is_vfio_noiommu(idev)) { + rc = iommufd_bind_iommu(idev); + if (rc) + goto err_out; + } else { + struct iommufd_group *igroup; + + /* + * Create a dummy igroup, lots of stuff expects ths igroup to be + * present, but a NULL igroup->group is OK + */ + igroup = iommufd_alloc_group(ictx, NULL); + if (IS_ERR(igroup)) { + rc = PTR_ERR(igroup); + goto err_out; + } + idev->igroup = igroup; + } + + if (!iommufd_selftest_is_mock_dev(dev)) + iommufd_ctx_get(ictx); /* The calling driver is a user until iommufd_device_unbind() */ refcount_inc(&idev->obj.users); - /* igroup refcount moves into iommufd_device */ - idev->igroup = igroup; /* * If the caller fails after this success it must call @@ -294,11 +334,10 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx, *id = idev->obj.id; return idev; -out_release_owner: - iommu_device_release_dma_owner(dev); -out_group_put: - iommufd_put_group(igroup); +err_out: + iommufd_object_abort_and_destroy(ictx, &idev->obj); return ERR_PTR(rc); + } EXPORT_SYMBOL_NS_GPL(iommufd_device_bind, "IOMMUFD"); @@ -512,6 +551,9 @@ static int iommufd_hwpt_attach_device(struct iommufd_hw_pagetable *hwpt, struct iommufd_attach_handle *handle; int rc; + if (is_vfio_noiommu(idev)) + return 0; + if (!iommufd_hwpt_compatible_device(hwpt, idev)) return -EINVAL; @@ -559,6 +601,9 @@ static void iommufd_hwpt_detach_device(struct iommufd_hw_pagetable *hwpt, { struct iommufd_attach_handle *handle; + if (is_vfio_noiommu(idev)) + return; + handle = iommufd_device_get_attach_handle(idev, pasid); if (pasid == IOMMU_NO_PASID) iommu_detach_group_handle(hwpt->domain, idev->igroup->group); @@ -577,6 +622,9 @@ static int iommufd_hwpt_replace_device(struct iommufd_device *idev, struct iommufd_attach_handle *handle, *old_handle; int rc; + if (is_vfio_noiommu(idev)) + return 0; + if (!iommufd_hwpt_compatible_device(hwpt, idev)) return -EINVAL; @@ -652,7 +700,7 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt, goto err_release_devid; } - if (attach_resv) { + if (attach_resv && !is_vfio_noiommu(idev)) { rc = iommufd_device_attach_reserved_iova(idev, hwpt_paging); if (rc) goto err_release_devid; -- 2.34.1