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author | Lu Baolu <baolu.lu@linux.intel.com> | 2024-03-05 20:21:17 +0800 |
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committer | Joerg Roedel <jroedel@suse.de> | 2024-03-06 17:35:56 +0100 |
commit | 0061ffe289e19caabeea8103e69cb0f1896e34d8 (patch) | |
tree | 5466b6d065c9294e9f71422351a1ec6cbcb2ae99 /drivers/iommu | |
parent | 80a9b50c0b9e297669a8a400eb35468cd87a9aed (diff) | |
download | linux-stable-0061ffe289e19caabeea8103e69cb0f1896e34d8.tar.gz linux-stable-0061ffe289e19caabeea8103e69cb0f1896e34d8.tar.bz2 linux-stable-0061ffe289e19caabeea8103e69cb0f1896e34d8.zip |
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 <jgg@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20240305013305.204605-2-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers/iommu')
-rw-r--r-- | drivers/iommu/iommu.c | 19 |
1 files changed, 15 insertions, 4 deletions
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); |