From 0061ffe289e19caabeea8103e69cb0f1896e34d8 Mon Sep 17 00:00:00 2001 From: Lu Baolu Date: Tue, 5 Mar 2024 20:21:17 +0800 Subject: iommu: Add static iommu_ops->release_domain The current device_release callback for individual iommu drivers does the following: 1) Silent IOMMU DMA translation: It detaches any existing domain from the device and puts it into a blocking state (some drivers might use the identity state). 2) Resource release: It releases resources allocated during the device_probe callback and restores the device to its pre-probe state. Step 1 is challenging for individual iommu drivers because each must check if a domain is already attached to the device. Additionally, if a deferred attach never occurred, the device_release should avoid modifying hardware configuration regardless of the reason for its call. To simplify this process, introduce a static release_domain within the iommu_ops structure. It can be either a blocking or identity domain depending on the iommu hardware. The iommu core will decide whether to attach this domain before the device_release callback, eliminating the need for repetitive code in various drivers. Consequently, the device_release callback can focus solely on the opposite operations of device_probe, including releasing all resources allocated during that callback. Co-developed-by: Jason Gunthorpe Signed-off-by: Jason Gunthorpe Signed-off-by: Lu Baolu Reviewed-by: Kevin Tian Link: https://lore.kernel.org/r/20240305013305.204605-2-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel --- drivers/iommu/iommu.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) (limited to 'drivers/iommu/iommu.c') diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index d14413916f93..cd1210026ac5 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -463,13 +463,24 @@ static void iommu_deinit_device(struct device *dev) /* * release_device() must stop using any attached domain on the device. - * If there are still other devices in the group they are not effected + * If there are still other devices in the group, they are not affected * by this callback. * - * The IOMMU driver must set the device to either an identity or - * blocking translation and stop using any domain pointer, as it is - * going to be freed. + * If the iommu driver provides release_domain, the core code ensures + * that domain is attached prior to calling release_device. Drivers can + * use this to enforce a translation on the idle iommu. Typically, the + * global static blocked_domain is a good choice. + * + * Otherwise, the iommu driver must set the device to either an identity + * or a blocking translation in release_device() and stop using any + * domain pointer, as it is going to be freed. + * + * Regardless, if a delayed attach never occurred, then the release + * should still avoid touching any hardware configuration either. */ + if (!dev->iommu->attach_deferred && ops->release_domain) + ops->release_domain->ops->attach_dev(ops->release_domain, dev); + if (ops->release_device) ops->release_device(dev); -- cgit v1.2.3