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Commit 8736b2c3 authored by Joerg Roedel's avatar Joerg Roedel
Browse files

iommu/amd: Implement notifiers for IOMMUv2 



Since pages are not pinned anymore we need notifications
when the VMM changes the page-tables. Use mmu_notifiers for
that.
Also use the task_exit notifier from the profiling subsystem
to shutdown all contexts related to this task.

Signed-off-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
parent 028eeacc

drivers/iommu/Kconfig

+2 −1
Original line number Diff line number Diff line
@@ -62,7 +62,8 @@ config AMD_IOMMU_STATS 


config AMD_IOMMU_V2

	tristate "AMD IOMMU Version 2 driver (EXPERIMENTAL)"

	depends on AMD_IOMMU && EXPERIMENTAL

	depends on AMD_IOMMU && PROFILING && EXPERIMENTAL

	select MMU_NOTIFIER

	---help---

	  This option enables support for the AMD IOMMUv2 features of the IOMMU

	  hardware. Select this option if you want to use devices that support

drivers/iommu/amd_iommu_v2.c

+176 −10
Original line number Diff line number Diff line
@@ -16,8 +16,10 @@ 
 * 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>
@@ -45,6 +47,7 @@ struct pasid_state { 
	atomic_t count;				/* Reference count */

	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 */
@@ -85,8 +88,16 @@ static DEFINE_SPINLOCK(ps_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 int task_exit(struct notifier_block *nb, unsigned long e, void *data);



static u16 device_id(struct pci_dev *pdev)

{
@@ -144,6 +155,11 @@ static void put_device_state_wait(struct device_state *dev_state) 


	free_device_state(dev_state);

}



static struct notifier_block profile_nb = {

	.notifier_call = task_exit,

};



static void link_pasid_state(struct pasid_state *pasid_state)

{

	spin_lock(&ps_lock);
@@ -294,6 +310,23 @@ static void put_pasid_state_wait(struct pasid_state *pasid_state) 
	free_pasid_state(pasid_state);

}



static void __unbind_pasid(struct pasid_state *pasid_state)

{

	struct iommu_domain *domain;



	domain = pasid_state->device_state->domain;



	amd_iommu_domain_clear_gcr3(domain, pasid_state->pasid);

	clear_pasid_state(pasid_state->device_state, pasid_state->pasid);



	/* Make sure no more pending faults are in the queue */

	flush_workqueue(iommu_wq);



	mmu_notifier_unregister(&pasid_state->mn, pasid_state->mm);



	put_pasid_state(pasid_state); /* Reference taken in bind() function */

}



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

{

	struct pasid_state *pasid_state;
@@ -303,12 +336,8 @@ static void unbind_pasid(struct device_state *dev_state, int pasid) 
		return;



	unlink_pasid_state(pasid_state);



	amd_iommu_domain_clear_gcr3(dev_state->domain, pasid);

	clear_pasid_state(dev_state, pasid);



	put_pasid_state(pasid_state); /* Reference taken in this function */

	put_pasid_state_wait(pasid_state); /* Reference from bind() function */

	__unbind_pasid(pasid_state);

	put_pasid_state_wait(pasid_state); /* Reference taken in this function */

}



static void free_pasid_states_level1(struct pasid_state **tbl)
@@ -361,6 +390,83 @@ static void free_pasid_states(struct device_state *dev_state) 
	free_page((unsigned long)dev_state->states);

}



static struct pasid_state *mn_to_state(struct mmu_notifier *mn)

{

	return container_of(mn, struct pasid_state, mn);

}



static void __mn_flush_page(struct mmu_notifier *mn,

			    unsigned long address)

{

	struct pasid_state *pasid_state;

	struct device_state *dev_state;



	pasid_state = mn_to_state(mn);

	dev_state   = pasid_state->device_state;



	amd_iommu_flush_page(dev_state->domain, pasid_state->pasid, address);

}



static int mn_clear_flush_young(struct mmu_notifier *mn,

				struct mm_struct *mm,

				unsigned long address)

{

	__mn_flush_page(mn, address);



	return 0;

}



static void mn_change_pte(struct mmu_notifier *mn,

			  struct mm_struct *mm,

			  unsigned long address,

			  pte_t pte)

{

	__mn_flush_page(mn, address);

}



static void mn_invalidate_page(struct mmu_notifier *mn,

			       struct mm_struct *mm,

			       unsigned long address)

{

	__mn_flush_page(mn, address);

}



static void mn_invalidate_range_start(struct mmu_notifier *mn,

				      struct mm_struct *mm,

				      unsigned long start, unsigned long end)

{

	struct pasid_state *pasid_state;

	struct device_state *dev_state;



	pasid_state = mn_to_state(mn);

	dev_state   = pasid_state->device_state;



	amd_iommu_domain_set_gcr3(dev_state->domain, pasid_state->pasid,

				  __pa(empty_page_table));

}



static void mn_invalidate_range_end(struct mmu_notifier *mn,

				    struct mm_struct *mm,

				    unsigned long start, unsigned long end)

{

	struct pasid_state *pasid_state;

	struct device_state *dev_state;



	pasid_state = mn_to_state(mn);

	dev_state   = pasid_state->device_state;



	amd_iommu_domain_set_gcr3(dev_state->domain, pasid_state->pasid,

				  __pa(pasid_state->mm->pgd));

}



static struct mmu_notifier_ops iommu_mn = {

	.clear_flush_young      = mn_clear_flush_young,

	.change_pte             = mn_change_pte,

	.invalidate_page        = mn_invalidate_page,

	.invalidate_range_start = mn_invalidate_range_start,

	.invalidate_range_end   = mn_invalidate_range_end,

};



static void set_pri_tag_status(struct pasid_state *pasid_state,

			       u16 tag, int status)

{
@@ -475,6 +581,50 @@ static struct notifier_block ppr_nb = { 
	.notifier_call = ppr_notifier,

};



static int task_exit(struct notifier_block *nb, unsigned long e, void *data)

{

	struct pasid_state *pasid_state;

	struct task_struct *task;



	task = data;



	/*

	 * Using this notifier is a hack - but there is no other choice

	 * at the moment. What I really want is a sleeping notifier that

	 * is called when an MM goes down. But such a notifier doesn't

	 * exist yet. The notifier needs to sleep because it has to make

	 * sure that the device does not use the PASID and the address

	 * space anymore before it is destroyed. This includes waiting

	 * for pending PRI requests to pass the workqueue. The

	 * MMU-Notifiers would be a good fit, but they use RCU and so

	 * they are not allowed to sleep. Lets see how we can solve this

	 * in a more intelligent way in the future.

	 */

again:

	spin_lock(&ps_lock);

	list_for_each_entry(pasid_state, &pasid_state_list, list) {

		struct device_state *dev_state;

		int pasid;



		if (pasid_state->task != task)

			continue;



		/* Drop Lock and unbind */

		spin_unlock(&ps_lock);



		dev_state = pasid_state->device_state;

		pasid     = pasid_state->pasid;



		unbind_pasid(dev_state, pasid);



		/* Task may be in the list multiple times */

		goto again;

	}

	spin_unlock(&ps_lock);



	return NOTIFY_OK;

}



int amd_iommu_bind_pasid(struct pci_dev *pdev, int pasid,

			 struct task_struct *task)

{
@@ -509,13 +659,16 @@ int amd_iommu_bind_pasid(struct pci_dev *pdev, int pasid, 
	pasid_state->mm           = get_task_mm(task);

	pasid_state->device_state = dev_state;

	pasid_state->pasid        = pasid;

	pasid_state->mn.ops       = &iommu_mn;



	if (pasid_state->mm == NULL)

		goto out_free;



	mmu_notifier_register(&pasid_state->mn, pasid_state->mm);



	ret = set_pasid_state(dev_state, pasid_state, pasid);

	if (ret)

		goto out_free;

		goto out_unregister;



	ret = amd_iommu_domain_set_gcr3(dev_state->domain, pasid,

					__pa(pasid_state->mm->pgd));
@@ -529,6 +682,9 @@ int amd_iommu_bind_pasid(struct pci_dev *pdev, int pasid, 
out_clear_state:

	clear_pasid_state(dev_state, pasid);



out_unregister:

	mmu_notifier_unregister(&pasid_state->mn, pasid_state->mm);



out_free:

	free_pasid_state(pasid_state);
@@ -689,15 +845,22 @@ static int __init amd_iommu_v2_init(void) 


	ret = -ENOMEM;

	iommu_wq = create_workqueue("amd_iommu_v2");

	if (iommu_wq == NULL) {

		ret = -ENOMEM;

	if (iommu_wq == NULL)

		goto out_free;

	}



	ret = -ENOMEM;

	empty_page_table = (u64 *)get_zeroed_page(GFP_KERNEL);

	if (empty_page_table == NULL)

		goto out_destroy_wq;



	amd_iommu_register_ppr_notifier(&ppr_nb);

	profile_event_register(PROFILE_TASK_EXIT, &profile_nb);



	return 0;



out_destroy_wq:

	destroy_workqueue(iommu_wq);



out_free:

	free_pages((unsigned long)state_table, get_order(state_table_size));
@@ -710,6 +873,7 @@ static void __exit amd_iommu_v2_exit(void) 
	size_t state_table_size;

	int i;



	profile_event_unregister(PROFILE_TASK_EXIT, &profile_nb);

	amd_iommu_unregister_ppr_notifier(&ppr_nb);



	flush_workqueue(iommu_wq);
@@ -734,6 +898,8 @@ static void __exit amd_iommu_v2_exit(void) 


	state_table_size = MAX_DEVICES * sizeof(struct device_state *);

	free_pages((unsigned long)state_table, get_order(state_table_size));



	free_page((unsigned long)empty_page_table);

}



module_init(amd_iommu_v2_init);