On Tue, Oct 24, 2023 at 03:00:49PM -0300, Jason Gunthorpe wrote:
On Tue, Oct 24, 2023 at 10:50:58AM -0700, Nicolin Chen wrote:
The point is for the user_data to always be available, the driver needs to check it if it is passed.
This should all be plumbed to allow drivers to also customize their paging domains too.
We don't have a use case of customizing the paging domains. And our selftest isn't covering this path. Nor the case is supported by the uAPI:
But this is the design, it is why everything is setup like this - we didn't create a new op to allocate nesting domains, we made a flexible user allocator.
458- * A kernel-managed HWPT will be created with the mappings from the given 459- * IOAS via the @pt_id. The @data_type for this allocation must be set to 460: * IOMMU_HWPT_DATA_NONE. The HWPT can be allocated as a parent HWPT for a 461- * nesting configuration by passing IOMMU_HWPT_ALLOC_NEST_PARENT via @flags. 462- *
Yes, that is the reality today. If someone comes to use the more complete interface they need to fix that comment..
Ack.
Also, if we do passing in the data, we'd need to...
280-static struct iommu_domain * 281-mock_domain_alloc_user(struct device *dev, u32 flags, 282- struct iommu_domain *parent, 283: const struct iommu_user_data *user_data) 284-{ 285- struct mock_iommu_domain *mock_parent; 286- struct iommu_hwpt_selftest user_cfg; 287- int rc; 288- 289: if (!user_data) { /* must be mock_domain */
...change this to if (!parent)...
Yes, this logic is not ideal. The parent is the request for nesting, not user_data. user_data is the generic creation parameters, which are not supported outside nesting Like this:
--- a/drivers/iommu/iommufd/selftest.c +++ b/drivers/iommu/iommufd/selftest.c @@ -286,14 +286,12 @@ mock_domain_alloc_user(struct device *dev, u32 flags, int rc; /* must be mock_domain */
if (!user_data) {
if (!parent) { struct mock_dev *mdev = container_of(dev, struct mock_dev, dev); bool has_dirty_flag = flags & IOMMU_HWPT_ALLOC_DIRTY_TRACKING; bool no_dirty_ops = mdev->flags & MOCK_FLAGS_DEVICE_NO_DIRTY;
if (parent)return ERR_PTR(-EINVAL);if (has_dirty_flag && no_dirty_ops)
if (user_data || (has_dirty_flag && no_dirty_ops)) return ERR_PTR(-EOPNOTSUPP); return __mock_domain_alloc_paging(IOMMU_DOMAIN_UNMANAGED, has_dirty_flag);
Yea.. Then the vt-d driver needs a similar change too (@Yi) as I found it almost doing the same: https://lore.kernel.org/linux-iommu/20231024151412.50046-8-yi.l.liu@intel.co...
Thanks Nic