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iommu/amd: Implement mmu_notifier_release call-back

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Since mmu_notifier call-backs can sleep (because they use
SRCU now) we can use them to tear down PASID mappings. This
allows us to finally remove the hack to use the task_exit
notifier from oprofile to get notified when a process dies.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Tested-by: Jay Cornwall <Jay.Cornwall@amd.com>
This commit is contained in:
Joerg Roedel 2014-05-20 23:18:24 +02:00
parent 741669c765
commit a40d4c67d7
1 changed files with 35 additions and 56 deletions
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91
drivers/iommu/amd_iommu_v2.c
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@ -101,7 +101,6 @@ 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)
{
@ -172,10 +171,6 @@ 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);
@ -393,7 +388,12 @@ static void free_pasid_states(struct device_state *dev_state)
continue;
put_pasid_state(pasid_state);
unbind_pasid(dev_state, i);
/*
* This will call the mn_release function and
* unbind the PASID
*/
mmu_notifier_unregister(&pasid_state->mn, pasid_state->mm);
}
if (dev_state->pasid_levels == 2)
@ -475,7 +475,24 @@ static void mn_invalidate_range_end(struct mmu_notifier *mn,
__pa(pasid_state->mm->pgd));
}
static void mn_release(struct mmu_notifier *mn, struct mm_struct *mm)
{
struct pasid_state *pasid_state;
struct device_state *dev_state;
might_sleep();
pasid_state = mn_to_state(mn);
dev_state = pasid_state->device_state;
if (pasid_state->device_state->inv_ctx_cb)
dev_state->inv_ctx_cb(dev_state->pdev, pasid_state->pasid);
unbind_pasid(dev_state, pasid_state->pasid);
}
static struct mmu_notifier_ops iommu_mn = {
.release = mn_release,
.clear_flush_young = mn_clear_flush_young,
.change_pte = mn_change_pte,
.invalidate_page = mn_invalidate_page,
@ -620,53 +637,6 @@ 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;
if (pasid_state->device_state->inv_ctx_cb)
dev_state->inv_ctx_cb(dev_state->pdev, 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)
{
@ -741,6 +711,7 @@ EXPORT_SYMBOL(amd_iommu_bind_pasid);
void amd_iommu_unbind_pasid(struct pci_dev *pdev, int pasid)
{
struct pasid_state *pasid_state;
struct device_state *dev_state;
u16 devid;
@ -757,7 +728,17 @@ void amd_iommu_unbind_pasid(struct pci_dev *pdev, int pasid)
if (pasid < 0 || pasid >= dev_state->max_pasids)
goto out;
unbind_pasid(dev_state, pasid);
pasid_state = get_pasid_state(dev_state, pasid);
if (pasid_state == NULL)
goto out;
/*
* Drop reference taken here. We are safe because we still hold
* the reference taken in the amd_iommu_bind_pasid function.
*/
put_pasid_state(pasid_state);
/* This will call the mn_release function and unbind the PASID */
mmu_notifier_unregister(&pasid_state->mn, pasid_state->mm);
out:
put_device_state(dev_state);
@ -963,7 +944,6 @@ static int __init amd_iommu_v2_init(void)
goto out_destroy_wq;
amd_iommu_register_ppr_notifier(&ppr_nb);
profile_event_register(PROFILE_TASK_EXIT, &profile_nb);
return 0;
@ -982,7 +962,6 @@ static void __exit amd_iommu_v2_exit(void)
if (!amd_iommu_v2_supported())
return;
profile_event_unregister(PROFILE_TASK_EXIT, &profile_nb);
amd_iommu_unregister_ppr_notifier(&ppr_nb);
flush_workqueue(iommu_wq);