path: root/drivers/vfio/vfio_iommu_spapr_tce.c

/*
 * VFIO: IOMMU DMA mapping support for TCE on POWER
 *
 * Copyright (C) 2013 IBM Corp.  All rights reserved.
 *     Author: Alexey Kardashevskiy <aik@ozlabs.ru>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Derived from original vfio_iommu_type1.c:
 * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
 *     Author: Alex Williamson <alex.williamson@redhat.com>
 */

#include <linux/module.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/err.h>
#include <linux/vfio.h>
#include <linux/vmalloc.h>
#include <asm/iommu.h>
#include <asm/tce.h>
#include <asm/mmu_context.h>

#define DRIVER_VERSION  "0.1"
#define DRIVER_AUTHOR   "aik@ozlabs.ru"
#define DRIVER_DESC     "VFIO IOMMU SPAPR TCE"

static void tce_iommu_detach_group(void *iommu_data,
		struct iommu_group *iommu_group);

static long try_increment_locked_vm(long npages)
{
	long ret = 0, locked, lock_limit;

	if (!current || !current->mm)
		return -ESRCH; /* process exited */

	if (!npages)
		return 0;

	down_write(&current->mm->mmap_sem);
	locked = current->mm->locked_vm + npages;
	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
	if (locked > lock_limit && !capable(CAP_IPC_LOCK))
		ret = -ENOMEM;
	else
		current->mm->locked_vm += npages;

	pr_debug("[%d] RLIMIT_MEMLOCK +%ld %ld/%ld%s\n", current->pid,
			npages << PAGE_SHIFT,
			current->mm->locked_vm << PAGE_SHIFT,
			rlimit(RLIMIT_MEMLOCK),
			ret ? " - exceeded" : "");

	up_write(&current->mm->mmap_sem);

	return ret;
}

static void decrement_locked_vm(long npages)
{
	if (!current || !current->mm || !npages)
		return; /* process exited */

	down_write(&current->mm->mmap_sem);
	if (WARN_ON_ONCE(npages > current->mm->locked_vm))
		npages = current->mm->locked_vm;
	current->mm->locked_vm -= npages;
	pr_debug("[%d] RLIMIT_MEMLOCK -%ld %ld/%ld\n", current->pid,
			npages << PAGE_SHIFT,
			current->mm->locked_vm << PAGE_SHIFT,
			rlimit(RLIMIT_MEMLOCK));
	up_write(&current->mm->mmap_sem);
}

/*
 * VFIO IOMMU fd for SPAPR_TCE IOMMU implementation
 *
 * This code handles mapping and unmapping of user data buffers
 * into DMA'ble space using the IOMMU
 */

struct tce_iommu_group {
	struct list_head next;
	struct iommu_group *grp;
};

/*
 * The container descriptor supports only a single group per container.
 * Required by the API as the container is not supplied with the IOMMU group
 * at the moment of initialization.
 */
struct tce_container {
	struct mutex lock;
	bool enabled;
	bool v2;
	unsigned long locked_pages;
	struct iommu_table *tables[IOMMU_TABLE_GROUP_MAX_TABLES];
	struct list_head group_list;
};

static long tce_iommu_unregister_pages(struct tce_container *container,
		__u64 vaddr, __u64 size)
{
	struct mm_iommu_table_group_mem_t *mem;

	if