[v5,2/6] iommufd: Add IOMMU_HWPT_INVALIDATE

Commit Message

Yi Liu Oct. 20, 2023, 9:24 a.m. UTC

In nested translation, the stage-1 page table is user-managed but cached
by the IOMMU hardware, so an update on present page table entries in the
stage-1 page table should be followed with a cache invalidation.

Add an IOMMU_HWPT_INVALIDATE ioctl to support such a cache invalidation.
It takes hwpt_id to specify the iommu_domain, and a multi-entry array to
support multiple invalidation requests in one ioctl.

Check cache_invalidate_user op in the iommufd_hw_pagetable_alloc_nested,
since all nested domains need that.

Co-developed-by: Nicolin Chen <[e-mail]>
Signed-off-by: Nicolin Chen <[e-mail]>
Signed-off-by: Yi Liu <[e-mail]>
---
 drivers/iommu/iommufd/hw_pagetable.c    | 35 ++++++++++++++++++++++++
 drivers/iommu/iommufd/iommufd_private.h |  9 +++++++
 drivers/iommu/iommufd/main.c            |  3 +++
 include/uapi/linux/iommufd.h            | 36 +++++++++++++++++++++++++
 4 files changed, 83 insertions(+)

Patch

diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 362c694aac9b..6090d59c4982 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -238,6 +238,11 @@  iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx,
 		rc = -EINVAL;
 		goto out_abort;
 	}
+	/* 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;
+	}
 	return hwpt_nested;
 
 out_abort:
@@ -323,3 +328,33 @@  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 iommu_user_data_array data_array = {
+		.type = cmd->req_type,
+		.uptr = u64_to_user_ptr(cmd->reqs_uptr),
+		.entry_len = cmd->req_len,
+		.entry_num = cmd->req_num,
+	};
+	struct iommufd_hw_pagetable *hwpt;
+	int rc = 0;
+
+	if (cmd->req_type == IOMMU_HWPT_DATA_NONE)
+		return -EINVAL;
+	if (!cmd->reqs_uptr || !cmd->req_len || !cmd->req_num)
+		return -EINVAL;
+
+	hwpt = iommufd_hw_pagetable_get_nested(ucmd, cmd->hwpt_id);
+	if (IS_ERR(hwpt))
+		return PTR_ERR(hwpt);
+
+	rc = hwpt->domain->ops->cache_invalidate_user(hwpt->domain, &data_array,
+						      &cmd->out_driver_error_code);
+	cmd->req_num = data_array.entry_num;
+	if (iommufd_ucmd_respond(ucmd, sizeof(*cmd)))
+		return -EFAULT;
+	iommufd_put_object(&hwpt->obj);
+	return rc;
+}
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index a829458fe762..7ec629599844 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -279,6 +279,7 @@  void iommufd_hwpt_paging_abort(struct iommufd_object *obj);
 void iommufd_hwpt_nested_destroy(struct iommufd_object *obj);
 void iommufd_hwpt_nested_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)
@@ -300,6 +301,14 @@  static inline void iommufd_hw_pagetable_put(struct iommufd_ctx *ictx,
 	refcount_dec(&hwpt->obj.users);
 }
 
+static inline struct iommufd_hw_pagetable *
+iommufd_hw_pagetable_get_nested(struct iommufd_ucmd *ucmd, u32 id)
+{
+	return container_of(iommufd_get_object(ucmd->ictx, id,
+					       IOMMUFD_OBJ_HWPT_NESTED),
+			    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 f94c14f20918..1f2d2d262e12 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -307,6 +307,7 @@  union ucmd_buffer {
 	struct iommu_destroy destroy;
 	struct iommu_hw_info info;
 	struct iommu_hwpt_alloc hwpt;
+	struct iommu_hwpt_invalidate cache;
 	struct iommu_ioas_alloc alloc;
 	struct iommu_ioas_allow_iovas allow_iovas;
 	struct iommu_ioas_copy ioas_copy;
@@ -342,6 +343,8 @@  static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
 		 __reserved),
 	IOCTL_OP(IOMMU_HWPT_ALLOC, iommufd_hwpt_alloc, struct iommu_hwpt_alloc,
 		 __reserved),
+	IOCTL_OP(IOMMU_HWPT_INVALIDATE, iommufd_hwpt_invalidate,
+		 struct iommu_hwpt_invalidate, out_driver_error_code),
 	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 d82bc663c5cd..fc305a48ab81 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_GET_HW_INFO,
+	IOMMUFD_CMD_HWPT_INVALIDATE,
 };
 
 /**
@@ -477,4 +478,39 @@  struct iommu_hw_info {
 	__u32 __reserved;
 };
 #define IOMMU_GET_HW_INFO _IO(IOMMUFD_TYPE, IOMMUFD_CMD_GET_HW_INFO)
+
+/**
+ * struct iommu_hwpt_invalidate - ioctl(IOMMU_HWPT_INVALIDATE)
+ * @size: sizeof(struct iommu_hwpt_invalidate)
+ * @hwpt_id: HWPT ID of a nested HWPT for cache invalidation
+ * @reqs_uptr: User pointer to an array having @req_num of cache invalidation
+ *             requests. The request entries in the array are of fixed width
+ *             @req_len, and contain a user data structure for invalidation
+ *             request specific to the given hardware page table.
+ * @req_type: One of enum iommu_hwpt_data_type, defining the data type of all
+ *            the entries in the invalidation request array. It should suit
+ *            with the data_type passed per the allocation of the hwpt pointed
+ *            by @hwpt_id.
+ * @req_len: Length (in bytes) of a request entry in the request array
+ * @req_num: Input the number of cache invalidation requests in the array.
+ *           Output the number of requests successfully handled by kernel.
+ * @out_driver_error_code: Report a driver speicifc error code upon failure.
+ *                         It's optional, driver has a choice to fill it or
+ *                         not.
+ *
+ * Invalidate the iommu cache for user-managed page table. Modifications on a
+ * user-managed page table should be followed by this operation to sync cache.
+ * Each ioctl can support one or more cache invalidation requests in the array
+ * that has a total size of @req_len * @req_num.
+ */
+struct iommu_hwpt_invalidate {
+	__u32 size;
+	__u32 hwpt_id;
+	__aligned_u64 reqs_uptr;
+	__u32 req_type;
+	__u32 req_len;
+	__u32 req_num;
+	__u32 out_driver_error_code;
+};
+#define IOMMU_HWPT_INVALIDATE _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_INVALIDATE)
 #endif