path: root/drivers/iommu/amd_iommu_v2.c

/*
 * Copyright (C) 2010-2012 Advanced Micro Devices, Inc.
 * Author: Joerg Roedel <joerg.roedel@amd.com>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/mmu_notifier.h>
#include <linux/amd-iommu.h>
#include <linux/mm_types.h>
#include <linux/profile.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/iommu.h>
#include <linux/wait.h>
#include <linux/pci.h>
#include <linux/gfp.h>

#include "amd_iommu_types.h"
#include "amd_iommu_proto.h"

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Joerg Roedel <joerg.roedel@amd.com>");

#define MAX_DEVICES		0x10000
#define PRI_QUEUE_SIZE		512

struct pri_queue {
	atomic_t inflight;
	bool finish;
	int status;
};

struct pasid_state {
	struct list_head list;			/* For global state-list */
	atomic_t count;				/* Reference count */
	unsigned mmu_notifier_count;		/* Counting nested mmu_notifier
						   calls */
	struct task_struct *task;		/* Task bound to this PASID */
	struct mm_struct *mm;			/* mm_struct for the faults */
	struct mmu_notifier mn;                 /* mmu_otifier handle */
	struct pri_queue pri[PRI_QUEUE_SIZE];	/* PRI tag states */
	struct device_state *device_state;	/* Link to our device_state */
	int pasid;				/* PASID index */
	spinlock_t lock;			/* Protect pri_queues and
						   mmu_notifer_count */
	wait_queue_head_t wq;			/* To wait for count == 0 */
};

struct device_state {
	struct list_head list;
	u16 devid;
	atomic_t count;
	struct pci_dev *pdev;
	struct pasid_state **states;
	struct iommu_domain *domain;
	int pasid_levels;
	int max_pasids;
	amd_iommu_invalid_ppr_cb inv_ppr_cb;
	amd_iommu_invalidate_ctx inv_ctx_cb;
	spinlock_t lock;
	wait_queue_head_t wq;
};

struct fault {
	struct work_struct work;
	struct device_state *dev_state;
	struct pasid_state *state;
	struct mm_struct *mm;
	u64 address;
	u16 devid;
	u16 pasid;
	u16 tag;
	u16 finish;
	u16 flags;
};

static LIST_HEAD(state_list);
static spinlock_t state_lock;

static struct workqueue_struct *iommu_wq;

/*
 * Empty page table - Used between
 * mmu_notifier_invalidate_range_start and
 * mmu_notifier_invalidate_range_end
 */
static u64 *empty_page_table;

static void free_pasid_states(struct device_state *dev_state);
static void unbind_pasid(struct device_state *dev_state, int pasid);

static u16 device_id(struct pci_dev *pdev)
{
	u16 devid;

	devid = pdev->bus->number;
	devid = (devid << 8) | pdev->devfn;

	return devid;
}

static struct device_state *__get_device_state(u16 devid)
{
	struct device_state *dev_state;

	list_for_each_entry(dev_state, &state_list, list) {
		if (dev_state->devid == devid)
			return dev_state;
	}

	return NULL;
}

static struct device_state *get_device_state(u16 devid)
{
	struct device_state *dev_state;
	unsigned long flags;

	spin_lock_irqsave(&state_lock, flags);
	dev_state = __get_device_state(devid);
	if (dev_state != NULL)
		atomic_inc(&dev_state->count);
	spin_unlock_irqrestore(&state_lock, flags);

	return dev_state;
}

static void free_device_state(struct device_state *dev_state)
{
	/*
	 * First detach device from domain - No more PRI requests will arrive
	 * from that device after it is unbound from the IOMMUv2 domain.
	 */
	iommu_detach_device(dev_state->domain, &dev_state->pdev->dev);

	/* Everything is down now, free the IOMMUv2 domain */
	iommu_domain_free(dev_state->domain);

	/* Finally get rid of the device-state */
	kfree(dev_state);
}

static void put_device_state(struct device_state *dev_state)
{
	if (atomic_dec_and_test(&dev_state->count))
		wake_up(&dev_state->wq);
}

static void put_device_state_wait(struct device_state *dev_state)
{
	DEFINE_WAIT(wait);

	prepare_to_wait(&dev_state->wq, &wait, TASK_UNINTERRUPTIBLE);
	if (!atomic_dec_and_test(&dev_state->count))
		schedule();
	finish_wait(&dev_state->wq, &wait);

	free_device_state(dev_state);
}

/* Must be called under dev_state->lock */
static struct pasid_state **__get_pasid_state_ptr(struct device_state *dev_state,
						  int pasid, bool alloc)
{
	struct pasid_state **root, **ptr;
	int level, index;

	level = dev_state->pasid_levels;
	root  = dev_state->states;

	while (true) {

		index = (pasid >> (9 * level)) & 0x1ff;
		ptr   = &root[