[PATCH v2 07/11] iommufd: Add IOMMU_HWPT_INVALIDATE

Yi Liu
2023-05-11T14:43:08Z

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 IOTLB invalidation.

Co-developed-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
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 | 26 ++++++++++++++
4 files changed, 83 insertions(+)

diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index e84270eb6e49..8206367b8d83 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -300,3 +300,48 @@ 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) {
+ 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;
+ 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;
+
+ rc = copy_struct_from_user(cmd, klen,
+ u64_to_user_ptr(user_ptr), user_data_len);
+ if (rc)
+ goto out_put_hwpt;
+
+ rc = hwpt->domain->ops->cache_invalidate_user(hwpt->domain, cmd);
+out_put_hwpt:
+ iommufd_put_object(&hwpt->obj);
+ return rc;
+}
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 9fe807e0aed6..1f9f48e45e05 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -268,6 +268,7 @@ iommufd_hw_pagetable_detach(struct iommufd_device *idev);
void iommufd_hw_pagetable_destroy(struct iommufd_object *obj);
void iommufd_hw_pagetable_abort(struct iommufd_object *obj);
int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd);
+int iommufd_hwpt_invalidate(struct iommufd_ucmd *ucmd);

static inline void iommufd_hw_pagetable_put(struct iommufd_ctx *ictx,
struct iommufd_hw_pagetable *hwpt)
@@ -279,6 +280,14 @@ static inline void iommufd_hw_pagetable_put(struct iommufd_ctx *ictx,
refcount_dec(&hwpt->obj.users);
}

+static inline struct iommufd_hw_pagetable *
+iommufd_get_hwpt(struct iommufd_ucmd *ucmd, u32 id)
+{
+ return container_of(iommufd_get_object(ucmd->ictx, id,
+ IOMMUFD_OBJ_HW_PAGETABLE),
+ struct iommufd_hw_pagetable, obj);
+}
+
struct iommufd_group {
struct kref ref;
struct mutex lock;
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index ac81403ba78e..d80c312f4ebe 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -270,6 +270,7 @@ union ucmd_buffer {
struct iommu_destroy destroy;
struct iommu_hwpt_alloc hwpt;
struct iommu_hw_info info;
+ struct iommu_hwpt_invalidate cache;
struct iommu_ioas_alloc alloc;
struct iommu_ioas_allow_iovas allow_iovas;
struct iommu_ioas_copy ioas_copy;
@@ -305,6 +306,8 @@ static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
data_uptr),
IOCTL_OP(IOMMU_DEVICE_GET_HW_INFO, iommufd_device_get_hw_info,
struct iommu_hw_info, __reserved),
+ IOCTL_OP(IOMMU_HWPT_INVALIDATE, iommufd_hwpt_invalidate,
+ struct iommu_hwpt_invalidate, data_uptr),
IOCTL_OP(IOMMU_IOAS_ALLOC, iommufd_ioas_alloc_ioctl,
struct iommu_ioas_alloc, out_ioas_id),
IOCTL_OP(IOMMU_IOAS_ALLOW_IOVAS, iommufd_ioas_allow_iovas,
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 699e735828db..6b82ef6d268b 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -47,6 +47,7 @@ enum {
IOMMUFD_CMD_VFIO_IOAS,
IOMMUFD_CMD_HWPT_ALLOC,
IOMMUFD_CMD_DEVICE_GET_HW_INFO,
+ IOMMUFD_CMD_HWPT_INVALIDATE,
};

/**
@@ -444,4 +445,29 @@ struct iommu_hw_info {
__u32 __reserved;
};
#define IOMMU_DEVICE_GET_HW_INFO _IO(IOMMUFD_TYPE, IOMMUFD_CMD_DEVICE_GET_HW_INFO)
+
+/**
+ * struct iommu_hwpt_invalidate - ioctl(IOMMU_HWPT_INVALIDATE)
+ * @size: sizeof(struct iommu_hwpt_invalidate)
+ * @hwpt_id: HWPT ID of target hardware page table for the invalidation
+ * @data_len: Length of the type specific data
+ * @__reserved: Must be 0
+ * @data_uptr: User pointer to the type specific data
+ *
+ * Invalidate the iommu cache for user-managed page table. Modifications
+ * on user-managed page table should be followed with this operation to
+ * sync the IOTLB. The data in @data_uptr differs per the hwpt type.
+ *
+ * +==============================+========================================+
+ * | @hwpt_type | Data structure in @data_uptr |
+ * +------------------------------+----------------------------------------+
+ */
+struct iommu_hwpt_invalidate {
+ __u32 size;
+ __u32 hwpt_id;
+ __u32 data_len;
+ __u32 __reserved;
+ __aligned_u64 data_uptr;
+};
+#define IOMMU_HWPT_INVALIDATE _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_INVALIDATE)
#endif
--
2.34.1