On Mon, Jul 24, 2023 at 04:03:58AM -0700, Yi Liu wrote:
> In nested translation, the stage-1 page table is user-managed and used by
> IOMMU hardware, so update of any present page table entry in the stage-1
> page table should be followed with an IOTLB invalidation.
>
> This adds IOMMU_HWPT_INVALIDATE for stage-1 IOTLB invalidation.
>
> 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 | 45 +++++++++++++++++++++++++
> drivers/iommu/iommufd/iommufd_private.h | 9 +++++
> drivers/iommu/iommufd/main.c | 3 ++
> include/uapi/linux/iommufd.h | 22 ++++++++++++
> 4 files changed, 79 insertions(+)
>
> diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
> index 97e4114226de..9064e6d181b4 100644
> --- a/drivers/iommu/iommufd/hw_pagetable.c
> +++ b/drivers/iommu/iommufd/hw_pagetable.c
> @@ -286,3 +286,48 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
> iommufd_put_object(&idev->obj);
> return rc;
> }
> +
> +int iommufd_hwpt_invalidate(struct iommufd_ucmd *ucmd)
> +{
> + struct iommu_hwpt_invalidate *cmd = ucmd->cmd;
> + struct iommufd_hw_pagetable *hwpt;
> + u32 user_data_len, klen;
> + u64 user_ptr;
> + int rc = 0;
> +
> + if (!cmd->data_len || cmd->__reserved)
> + return -EOPNOTSUPP;
> +
> + hwpt = iommufd_get_hwpt(ucmd, cmd->hwpt_id);
> + if (IS_ERR(hwpt))
> + return PTR_ERR(hwpt);
> +
> + /* Do not allow any kernel-managed hw_pagetable */
> + if (!hwpt->parent) {
I don't think this is needed because:
> + rc = -EINVAL;
> + goto out_put_hwpt;
> + }
> +
> + klen = hwpt->domain->ops->cache_invalidate_user_data_len;
> + if (!hwpt->domain->ops->cache_invalidate_user || !klen) {
> + rc = -EOPNOTSUPP;
We need to get to a place where the drivers are providing proper ops
for the domains, so this op should never exist for a paging domain.
And return EINVAL here instead.
> + goto out_put_hwpt;
> + }
> +
> + /*
> + * Copy the needed fields before reusing the ucmd buffer, this
> + * avoids memory allocation in this path.
> + */
> + user_ptr = cmd->data_uptr;
> + user_data_len = cmd->data_len;
Uhh, who checks that klen < the temporary stack struct?
Jason
