Re: [PATCH 07/12] iommufd: Add IOMMU_HWPT_INVALIDATE

On 3/9/23 4:09 PM, Yi Liu wrote:

In nested translation, the stage-1 page table is user-managed and used by IOMMU hardware, so destroying mappings in the stage-1 page table should be followed with an IOTLB invalidation.

s/destroying mappings/update of any present page table entry/

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 | 56 +++++++++++++++++++++++++ drivers/iommu/iommufd/iommufd_private.h | 9 ++++ drivers/iommu/iommufd/main.c | 3 ++ include/uapi/linux/iommufd.h | 27 ++++++++++++ 4 files changed, 95 insertions(+)

diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c index 64e7cf7142e1..67facca98de1 100644 --- a/drivers/iommu/iommufd/hw_pagetable.c +++ b/drivers/iommu/iommufd/hw_pagetable.c @@ -284,3 +284,59 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd) iommufd_put_object(&idev->obj); return rc; }

+/*

• • size of page table type specific invalidate_info, indexed by
• • enum iommu_hwpt_type.
• */

+static const size_t iommufd_hwpt_invalidate_info_size[] = {};

+int iommufd_hwpt_invalidate(struct iommufd_ucmd *ucmd) +{

• struct iommu_hwpt_invalidate *cmd = ucmd->cmd;
• struct iommufd_hw_pagetable *hwpt;
• u64 user_ptr;
• u32 user_data_len, klen;
• int rc = 0;
• /*

• * For a user-managed HWPT, type should not be IOMMU_HWPT_TYPE_DEFAULT.
  

• * data_len should not exceed the size of iommufd_invalidate_buffer.
  

• */
  

• if (cmd->data_type == IOMMU_HWPT_TYPE_DEFAULT || !cmd->data_len ||

•    cmd->data_type >= ARRAY_SIZE(iommufd_hwpt_invalidate_info_size))
  

"data_len should not exceed the size of iommufd_invalidate_buffer."

How is this checked?

• 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 = iommufd_hwpt_invalidate_info_size[cmd->data_type];
• if (!klen) {

• rc = -EINVAL;
  

• 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;

Is it a valid case if "user_data_len < klen"?

• rc = copy_struct_from_user(cmd, klen,

• 		   u64_to_user_ptr(user_ptr), user_data_len);
  

• if (rc)

• goto out_put_hwpt;
  

• 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 182c074eecdc..d879264d1acf 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -265,6 +265,7 @@ struct iommufd_hw_pagetable * iommufd_hw_pagetable_detach(struct iommufd_device *idev); void iommufd_hw_pagetable_destroy(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) @@ -276,6 +277,14 @@ 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 7ab1e2c638a1..2cf45f65b637 100644 --- a/drivers/iommu/iommufd/main.c +++ b/drivers/iommu/iommufd/main.c @@ -263,6 +263,7 @@ 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;

@@ -298,6 +299,8 @@ 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 48781ff40a37..d0962c41f8d6 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, };

/** @@ -447,4 +448,30 @@ 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_type: One of enum iommu_hwpt_type
• • @data_len: Length of the type specific data
• • @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. This is only needed by user-managed hw_pagetables, so
• • the @data_type should never be IOMMU_HWPT_TYPE_DEFAULT.
• • +==============================+========================================+
• • | @data_type | Data structure in @data_uptr |
• • +------------------------------+----------------------------------------+
• */

+struct iommu_hwpt_invalidate {

• __u32 size;
• __u32 hwpt_id;
• __u32 data_type;
• __u32 data_len;
• __aligned_u64 data_uptr;

+}; +#define IOMMU_HWPT_INVALIDATE _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_INVALIDATE) #endif

Best regards, baolu