From: Lu Baolu baolu.lu@linux.intel.com
Introduce a new iommu_domain op to create domains owned by userspace, e.g. through iommufd. These domains have a few different properties compares to kernel owned domains:
- They may be MANAGED domains, but created with special parameters. For instance aperture size changes/number of levels, different IOPTE formats, or other things necessary to make a vIOMMU work
- We have to track all the memory allocations with GFP_KERNEL_ACCOUNT to make the cgroup sandbox stronger
- Device-specialty domains, such as NESTED domains can be created by iommufd.
The new op clearly says the domain is being created by IOMMUFD, that the domain is intended for userspace use, and it provides a way to pass a driver specific uAPI structure to customize the created domain to exactly what the vIOMMU userspace driver requires.
iommu drivers that cannot support VFIO/IOMMUFD should not support this op. This includes any driver that cannot provide a fully functional UNMANAGED domain.
This op chooses to make the special parameters opaque to the core. This suits the current usage model where accessing any of the IOMMU device special parameters does require a userspace driver that matches the kernel driver. If a need for common parameters, implemented similarly by several drivers, arises then there is room in the design to grow a generic parameter set as well.
This new op for now is only supposed to be used by iommufd, hence no wrapper for it. iommufd would call the callback directly. As for domain free, iommufd would use iommu_domain_free().
Suggested-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Lu Baolu baolu.lu@linux.intel.com Signed-off-by: Yi Liu yi.l.liu@intel.com --- include/linux/iommu.h | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 97b398d19fd2..214e3eb9bc86 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -230,6 +230,7 @@ struct iommu_iotlb_gather { * after use. Return the data buffer if success, or ERR_PTR on * failure. * @domain_alloc: allocate iommu domain + * @domain_alloc_user: allocate user iommu domain * @probe_device: Add device to iommu driver handling * @release_device: Remove device from iommu driver handling * @probe_finalize: Do final setup work after the device is added to an IOMMU @@ -262,6 +263,9 @@ struct iommu_ops {
/* Domain allocation and freeing by the iommu driver */ struct iommu_domain *(*domain_alloc)(unsigned iommu_domain_type); + struct iommu_domain *(*domain_alloc_user)(struct device *dev, + struct iommu_domain *parent, + const void *user_data);
struct iommu_device *(*probe_device)(struct device *dev); void (*release_device)(struct device *dev);