diff options
| author | Nicolin Chen <nicolinc@nvidia.com> | 2022-10-17 16:01:22 -0700 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@nvidia.com> | 2022-11-01 14:39:59 -0300 |
| commit | 00208852d351ca6e4a8b9ff0c5376fa3a8ed8eaa (patch) | |
| tree | ead4c5a495cdd8f62b5da58fe099e8eb83f83895 /include/linux/iommu.h | |
| parent | 79218fd0b38bb05e8dcb80a49342836274046432 (diff) | |
iommu: Add return value rules to attach_dev op and APIs
Cases like VFIO wish to attach a device to an existing domain that was
not allocated specifically from the device. This raises a condition
where the IOMMU driver can fail the domain attach because the domain and
device are incompatible with each other.
This is a soft failure that can be resolved by using a different domain.
Provide a dedicated errno EINVAL from the IOMMU driver during attach that
the reason why the attach failed is because of domain incompatibility.
VFIO can use this to know that the attach is a soft failure and it should
continue searching. Otherwise, the attach will be a hard failure and VFIO
will return the code to userspace.
Update kdocs to add rules of return value to the attach_dev op and APIs.
Link: https://lore.kernel.org/r/bd56d93c18621104a0fa1b0de31e9b760b81b769.1666042872.git.nicolinc@nvidia.com
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'include/linux/iommu.h')
| -rw-r--r-- | include/linux/iommu.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 3c9da1f8979e..857898d102b3 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -266,6 +266,18 @@ struct iommu_ops { /** * struct iommu_domain_ops - domain specific operations * @attach_dev: attach an iommu domain to a device + * Return: + * * 0 - success + * * EINVAL - can indicate that device and domain are incompatible due to + * some previous configuration of the domain, in which case the + * driver shouldn't log an error, since it is legitimate for a + * caller to test reuse of existing domains. Otherwise, it may + * still represent some other fundamental problem + * * ENOMEM - out of memory + * * ENOSPC - non-ENOMEM type of resource allocation failures + * * EBUSY - device is attached to a domain and cannot be changed + * * ENODEV - device specific errors, not able to be attached + * * <others> - treated as ENODEV by the caller. Use is discouraged * @detach_dev: detach an iommu domain from a device * @map: map a physically contiguous memory region to an iommu domain * @map_pages: map a physically contiguous set of pages of the same size to |