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/* SPDX-License-Identifier: GPL-2.0-only */
/* Copyright (c) 2021-2022, NVIDIA CORPORATION & AFFILIATES
*/
#ifndef __IOMMUFD_PRIVATE_H
#define __IOMMUFD_PRIVATE_H
#include <linux/rwsem.h>
#include <linux/xarray.h>
#include <linux/refcount.h>
#include <linux/uaccess.h>
struct iommu_domain;
struct iommu_group;
struct iommufd_ctx {
struct file *file;
struct xarray objects;
u8 account_mode;
};
/*
* The IOVA to PFN map. The map automatically copies the PFNs into multiple
* domains and permits sharing of PFNs between io_pagetable instances. This
* supports both a design where IOAS's are 1:1 with a domain (eg because the
* domain is HW customized), or where the IOAS is 1:N with multiple generic
* domains. The io_pagetable holds an interval tree of iopt_areas which point
* to shared iopt_pages which hold the pfns mapped to the page table.
*
* The locking order is domains_rwsem -> iova_rwsem -> pages::mutex
*/
struct io_pagetable {
struct rw_semaphore domains_rwsem;
struct xarray domains;
struct xarray access_list;
unsigned int next_domain_id;
struct rw_semaphore iova_rwsem;
struct rb_root_cached area_itree;
/* IOVA that cannot become reserved, struct iopt_allowed */
struct rb_root_cached allowed_itree;
/* IOVA that cannot be allocated, struct iopt_reserved */
struct rb_root_cached reserved_itree;
u8 disable_large_pages;
unsigned long iova_alignment;
};
void iopt_init_table(struct io_pagetable *iopt);
void iopt_destroy_table(struct io_pagetable *iopt);
int iopt_get_pages(struct io_pagetable *iopt, unsigned long iova,
unsigned long length, struct list_head *pages_list);
void iopt_free_pages_list(struct list_head *pages_list);
enum {
IOPT_ALLOC_IOVA = 1 << 0,
};
int iopt_map_user_pages(struct iommufd_ctx *ictx, struct io_pagetable *iopt,
unsigned long *iova, void __user *uptr,
unsigned long length, int iommu_prot,
unsigned int flags);
int iopt_map_pages(struct io_pagetable *iopt, struct list_head *pages_list,
unsigned long length, unsigned long *dst_iova,
int iommu_prot, unsigned int flags);
int iopt_unmap_iova(struct io_pagetable *iopt, unsigned long iova,
unsigned long length, unsigned long *unmapped);
int iopt_unmap_all(struct io_pagetable *iopt, unsigned long *unmapped);
int iopt_table_add_domain(struct io_pagetable *iopt,
struct iommu_domain *domain);
void iopt_table_remove_domain(struct io_pagetable *iopt,
struct iommu_domain *domain);
int iopt_table_enforce_group_resv_regions(struct io_pagetable *iopt,
struct device *device,
struct iommu_group *group,
phys_addr_t *sw_msi_start);
int iopt_set_allow_iova(struct io_pagetable *iopt,
struct rb_root_cached *allowed_iova);
int iopt_reserve_iova(struct io_pagetable *iopt, unsigned long start,
unsigned long last, void *owner);
void iopt_remove_reserved_iova(struct io_pagetable *iopt, void *owner);
int iopt_cut_iova(struct io_pagetable *iopt, unsigned long *iovas,
size_t num_iovas);
void iopt_enable_large_pages(struct io_pagetable *iopt);
int iopt_disable_large_pages(struct io_pagetable *iopt);
struct iommufd_ucmd {
struct iommufd_ctx *ictx;
void __user *ubuffer;
u32 user_size;
void *cmd;
};
/* Copy the response in ucmd->cmd back to userspace. */
static inline int iommufd_ucmd_respond(struct iommufd_ucmd *ucmd,
size_t cmd_len)
{
if (copy_to_user(ucmd->ubuffer, ucmd->cmd,
min_t(size_t, ucmd->user_size, cmd_len)))
return -EFAULT;
return 0;
}
enum iommufd_object_type {
IOMMUFD_OBJ_NONE,
IOMMUFD_OBJ_ANY = IOMMUFD_OBJ_NONE,
};
/* Base struct for all objects with a userspace ID handle. */
struct iommufd_object {
struct rw_semaphore destroy_rwsem;
refcount_t users;
enum iommufd_object_type type;
unsigned int id;
};
static inline bool iommufd_lock_obj(struct iommufd_object *obj)
{
if (!down_read_trylock(&obj->destroy_rwsem))
return false;
if (!refcount_inc_not_zero(&obj->users)) {
up_read(&obj->destroy_rwsem);
return false;
}
return true;
}
struct iommufd_object *iommufd_get_object(struct iommufd_ctx *ictx, u32 id,
enum iommufd_object_type type);
static inline void iommufd_put_object(struct iommufd_object *obj)
{
refcount_dec(&obj->users);
up_read(&obj->destroy_rwsem);
}
/**
* iommufd_ref_to_users() - Switch from destroy_rwsem to users refcount
* protection
* @obj - Object to release
*
* Objects have two refcount protections (destroy_rwsem and the refcount_t
* users). Holding either of these will prevent the object from being destroyed.
*
* Depending on the use case, one protection or the other is appropriate. In
* most cases references are being protected by the destroy_rwsem. This allows
* orderly destruction of the object because iommufd_object_destroy_user() will
* wait for it to become unlocked. However, as a rwsem, it cannot be held across
* a system call return. So cases that have longer term needs must switch
* to the weaker users refcount_t.
*
* With users protection iommufd_object_destroy_user() will return false,
* refusing to destroy the object, causing -EBUSY to userspace.
*/
static inline void iommufd_ref_to_users(struct iommufd_object *obj)
{
up_read(&obj->destroy_rwsem);
/* iommufd_lock_obj() obtains users as well */
}
void iommufd_object_abort(struct iommufd_ctx *ictx, struct iommufd_object *obj);
void iommufd_object_abort_and_destroy(struct iommufd_ctx *ictx,
struct iommufd_object *obj);
void iommufd_object_finalize(struct iommufd_ctx *ictx,
struct iommufd_object *obj);
bool iommufd_object_destroy_user(struct iommufd_ctx *ictx,
struct iommufd_object *obj);
struct iommufd_object *_iommufd_object_alloc(struct iommufd_ctx *ictx,
size_t size,
enum iommufd_object_type type);
#define iommufd_object_alloc(ictx, ptr, type) \
container_of(_iommufd_object_alloc( \
ictx, \
sizeof(*(ptr)) + BUILD_BUG_ON_ZERO( \
offsetof(typeof(*(ptr)), \
obj) != 0), \
type), \
typeof(*(ptr)), obj)
struct iommufd_access {
unsigned long iova_alignment;
u32 iopt_access_list_id;
};
int iopt_add_access(struct io_pagetable *iopt, struct iommufd_access *access);
void iopt_remove_access(struct io_pagetable *iopt,
struct iommufd_access *access);
#endif
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