On 2023/10/17 02:44, Nicolin Chen wrote:
On Mon, Oct 16, 2023 at 08:59:07AM -0300, Jason Gunthorpe wrote:
On Mon, Oct 16, 2023 at 03:03:04PM +0800, Yi Liu wrote:
Current nesting series actually extends HWPT_ALLOC ioctl to accept user
data for allocating domain with vendor specific data. Nested translation
happens to be the usage of it. But nesting requires invalidation. If we
want to do further split, then this new series would be just "extending
HWPT_ALLOC to accept vendor specific data from userspace". But it will
lack of a user if nesting is separated. Is this acceptable? @Jason
I'd still like to include the nesting allocation and attach parts
though, even if they are not usable without invalidation ..
This is the latest series that I reworked (in bottom-up order):
iommu: Add a pair of helper to copy struct iommu_user_data{_array}
iommufd: Add IOMMU_HWPT_INVALIDATE
iommufd: Add a nested HW pagetable object
iommufd: Share iommufd_hwpt_alloc with IOMMUFD_OBJ_HWPT_NESTED
iommufd: Derive iommufd_hwpt_paging from iommufd_hw_pagetable
iommufd: Rename IOMMUFD_OBJ_HW_PAGETABLE to IOMMUFD_OBJ_HWPT_PAGING
iommufd/device: Add helpers to enforce/remove device reserved regions
iommu: Add IOMMU_DOMAIN_NESTED and cache_invalidate_user op
iommu: Pass in parent domain with user_data to domain_alloc_user op
following Jason's comment, it looks like we can just split the cache
invalidation path out. Then the above looks good after removing
"iommufd: Add IOMMU_HWPT_INVALIDATE" and also the cache_invalidate_user
callback in "iommu: Add IOMMU_DOMAIN_NESTED and cache_invalidate_user op".
Is it? @Jason
Perhaps we can have a preparatory series to merge first:
iommufd: Share iommufd_hwpt_alloc with IOMMUFD_OBJ_HWPT_NESTED
iommufd: Derive iommufd_hwpt_paging from iommufd_hw_pagetable
iommufd: Rename IOMMUFD_OBJ_HW_PAGETABLE to IOMMUFD_OBJ_HWPT_PAGING
iommufd/device: Add helpers to enforce/remove device reserved regions
Then next cycle would be basically 4 patches + selftests:
iommufd: Add IOMMU_HWPT_INVALIDATE
iommufd: Add a nested HW pagetable object
iommu: Add IOMMU_DOMAIN_NESTED and cache_invalidate_user op
iommu: Pass in parent domain with user_data to domain_alloc_user op
The preparatory series doesn't involve functional changes yet have
a good amount of pieces to simplify the "nested HW pagetable" that
is basically nested_alloc/abort/destroy.
>>> BTW. Do we still have unsolved issue on the invalidation path?
I'm not sure, there were so many different versions of it we need to
go back over it and check the dirver implementations again
Only this v4 has the latest array-based invalidation design. And
it should be straightforward for drivers to define entry/request
structures. It might be a bit rush to review/finalize it at the
stage of rc6 though.
yes, before v4, the cache invalidation path is simple and vendor
drivers have their own handling.
--
Regards,
Yi Liu
