On Fri, Oct 13, 2023 at 09:07:09PM -0300, Jason Gunthorpe wrote:
On Fri, Oct 13, 2023 at 01:58:59PM -0700, Nicolin Chen wrote:
On Fri, Oct 13, 2023 at 12:19:23PM -0300, Jason Gunthorpe wrote:
On Thu, Sep 21, 2023 at 12:51:31AM -0700, Yi Liu wrote:
IOMMU_HWPT_ALLOC already supports iommu_domain allocation for usersapce.
But it can only allocate a hw_pagetable that associates to a given IOAS,
i.e. only a kernel-managed hw_pagetable of IOMMU_HWPT_TYPE_DEFAULT type.
IOMMU drivers can now support user-managed hw_pagetables, for two-stage
translation use cases, that require user data input from the user space.
Extend the IOMMU_HWPT_ALLOC ioctl to accept non-default hwpt_type with a
type specified user data. Also, update the @pt_id to accept hwpt_id too
besides an ioas_id. Then, pass them to the downstream alloc_fn().
Co-developed-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
---
drivers/iommu/iommufd/hw_pagetable.c | 19 ++++++++++++++++++-
include/uapi/linux/iommufd.h | 23 +++++++++++++++++++++--
2 files changed, 39 insertions(+), 3 deletions(-)
Can we also come with a small vt-d patch that does implement an op for
this? Or is it too big?
It would be nice if we could wrap IOMMU_HWPT_ALLOC into one
self-contained series and another series for invalidate.
We now only use IOMMU_HWPT_ALLOC for nested domain allocations,
which won't be supported until the cache_invalidate_user ops is
preset?
/* e.g. the following piece is in iommufd_user_managed_hwpt_alloc */
+ /* Driver is buggy by missing cache_invalidate_user in domain_ops */
+ if (WARN_ON_ONCE(!hwpt->domain->ops->cache_invalidate_user)) {
+ rc = -EINVAL;
+ goto out_abort;
+ }
Hm. That hunk could migrate to the invalidate series.
I'm just leeary of doing the invalidation too considering how
complicated it is
OK. Let's see how Yi/Kevin/Baolu reply about the feasibility
with the VT-d driver. Then Yi and I can accordingly separate
the allocation part into a smaller series.