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;
+ }
Thanks
Nic
