[PATCH v8 02/10] iommufd: Add IOMMU_HWPT_INVALIDATE

Yi Liu
2023-12-27T16:14:02Z

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 data in one ioctl.

enum iommu_hwpt_invalidate_data_type is defined to tag the data type of
the entries in the multi-entry array.

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 | 41 +++++++++++++++++++++++
drivers/iommu/iommufd/iommufd_private.h | 10 ++++++
drivers/iommu/iommufd/main.c | 3 ++
include/uapi/linux/iommufd.h | 43 +++++++++++++++++++++++++
4 files changed, 97 insertions(+)

diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index cbb5df0a6c32..4e8711f19f72 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -371,3 +371,44 @@ int iommufd_hwpt_get_dirty_bitmap(struct iommufd_ucmd *ucmd)
iommufd_put_object(ucmd->ictx, &hwpt_paging->common.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->data_type,
+ .uptr = u64_to_user_ptr(cmd->data_uptr),
+ .entry_len = cmd->entry_len,
+ .entry_num = cmd->entry_num,
+ };
+ struct iommufd_hw_pagetable *hwpt;
+ u32 done_num = 0;
+ int rc;
+
+ if (cmd->__reserved) {
+ rc = -EOPNOTSUPP;
+ goto out;
+ }
+
+ if (cmd->entry_num && (!cmd->data_uptr || !cmd->entry_len)) {
+ rc = -EINVAL;
+ goto out;
+ }
+
+ hwpt = iommufd_get_hwpt_nested(ucmd, cmd->hwpt_id);
+ if (IS_ERR(hwpt)) {
+ rc = PTR_ERR(hwpt);
+ goto out;
+ }
+
+ rc = hwpt->domain->ops->cache_invalidate_user(hwpt->domain,
+ &data_array);
+ done_num = data_array.entry_num;
+
+ iommufd_put_object(ucmd->ictx, &hwpt->obj);
+out:
+ cmd->entry_num = done_num;
+ if (iommufd_ucmd_respond(ucmd, sizeof(*cmd)))
+ return -EFAULT;
+ return rc;
+}
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index abae041e256f..991f864d1f9b 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -328,6 +328,15 @@ iommufd_get_hwpt_paging(struct iommufd_ucmd *ucmd, u32 id)
IOMMUFD_OBJ_HWPT_PAGING),
struct iommufd_hwpt_paging, common.obj);
}
+
+static inline struct iommufd_hw_pagetable *
+iommufd_get_hwpt_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);
+}
+
int iommufd_hwpt_set_dirty_tracking(struct iommufd_ucmd *ucmd);
int iommufd_hwpt_get_dirty_bitmap(struct iommufd_ucmd *ucmd);

@@ -345,6 +354,7 @@ 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)
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index c9091e46d208..39b32932c61e 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -322,6 +322,7 @@ union ucmd_buffer {
struct iommu_hw_info info;
struct iommu_hwpt_alloc hwpt;
struct iommu_hwpt_get_dirty_bitmap get_dirty_bitmap;
+ struct iommu_hwpt_invalidate cache;
struct iommu_hwpt_set_dirty_tracking set_dirty_tracking;
struct iommu_ioas_alloc alloc;
struct iommu_ioas_allow_iovas allow_iovas;
@@ -360,6 +361,8 @@ static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
__reserved),
IOCTL_OP(IOMMU_HWPT_GET_DIRTY_BITMAP, iommufd_hwpt_get_dirty_bitmap,
struct iommu_hwpt_get_dirty_bitmap, data),
+ IOCTL_OP(IOMMU_HWPT_INVALIDATE, iommufd_hwpt_invalidate,
+ struct iommu_hwpt_invalidate, __reserved),
IOCTL_OP(IOMMU_HWPT_SET_DIRTY_TRACKING, iommufd_hwpt_set_dirty_tracking,
struct iommu_hwpt_set_dirty_tracking, __reserved),
IOCTL_OP(IOMMU_IOAS_ALLOC, iommufd_ioas_alloc_ioctl,
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 0b2bc6252e2c..824560c50ec6 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -49,6 +49,7 @@ enum {
IOMMUFD_CMD_GET_HW_INFO,
IOMMUFD_CMD_HWPT_SET_DIRTY_TRACKING,
IOMMUFD_CMD_HWPT_GET_DIRTY_BITMAP,
+ IOMMUFD_CMD_HWPT_INVALIDATE,
};

/**
@@ -613,4 +614,46 @@ struct iommu_hwpt_get_dirty_bitmap {
#define IOMMU_HWPT_GET_DIRTY_BITMAP _IO(IOMMUFD_TYPE, \
IOMMUFD_CMD_HWPT_GET_DIRTY_BITMAP)

+/**
+ * enum iommu_hwpt_invalidate_data_type - IOMMU HWPT Cache Invalidation
+ * Data Type
+ * @IOMMU_HWPT_INVALIDATE_DATA_VTD_S1: Invalidation data for VTD_S1
+ */
+enum iommu_hwpt_invalidate_data_type {
+ IOMMU_HWPT_INVALIDATE_DATA_VTD_S1,
+};
+
+/**
+ * struct iommu_hwpt_invalidate - ioctl(IOMMU_HWPT_INVALIDATE)
+ * @size: sizeof(struct iommu_hwpt_invalidate)
+ * @hwpt_id: ID of a nested HWPT for cache invalidation
+ * @data_uptr: User pointer to an array of driver-specific cache invalidation
+ * data.
+ * @data_type: One of enum iommu_hwpt_invalidate_data_type, defining the data
+ * type of all the entries in the invalidation request array. It
+ * should be a type supported by the hwpt pointed by @hwpt_id.
+ * @entry_len: Length (in bytes) of a request entry in the request array
+ * @entry_num: Input the number of cache invalidation requests in the array.
+ * Output the number of requests successfully handled by kernel.
+ * @__reserved: Must be 0.
+ *
+ * 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 @entry_len * @entry_num.
+ *
+ * An empty invalidation request array by setting @entry_num==0 is allowed, and
+ * @entry_len and @data_uptr would be ignored in this case. This can be used to
+ * check if the given @data_type is supported or not by kernel.
+ */
+struct iommu_hwpt_invalidate {
+ __u32 size;
+ __u32 hwpt_id;
+ __aligned_u64 data_uptr;
+ __u32 data_type;
+ __u32 entry_len;
+ __u32 entry_num;
+ __u32 __reserved;
+};
+#define IOMMU_HWPT_INVALIDATE _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_INVALIDATE)
#endif
--
2.34.1