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iommu/amd: Add pasid_state->invalid flag

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This is used to signal the ppr_notifer function that no more
faults should be processes on this pasid_state. This way we
can keep the pasid_state safely in the state-table so that
it can be freed in the amd_iommu_unbind_pasid() function.

This allows us to not hold a reference to the mm_struct
during the whole pasid-binding-time.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Tested-by: Oded Gabbay <Oded.Gabbay@amd.com>
This commit is contained in:
Joerg Roedel
2014-07-08 15:01:43 +02:00
parent dc88db7ee9
commit 53d340ef4a
1 changed files with 16 additions and 2 deletions
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18
drivers/iommu/amd_iommu_v2.c
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@@ -53,6 +53,7 @@ struct pasid_state {
struct pri_queue pri[PRI_QUEUE_SIZE]; /* PRI tag states */ struct pri_queue pri[PRI_QUEUE_SIZE]; /* PRI tag states */
struct device_state *device_state; /* Link to our device_state */ struct device_state *device_state; /* Link to our device_state */
int pasid; /* PASID index */ int pasid; /* PASID index */
bool invalid; /* Used during teardown */
spinlock_t lock; /* Protect pri_queues and spinlock_t lock; /* Protect pri_queues and
mmu_notifer_count */ mmu_notifer_count */
wait_queue_head_t wq; /* To wait for count == 0 */ wait_queue_head_t wq; /* To wait for count == 0 */
@@ -306,8 +307,17 @@ static void unbind_pasid(struct pasid_state *pasid_state)
domain = pasid_state->device_state->domain; domain = pasid_state->device_state->domain;
/*
* Mark pasid_state as invalid, no more faults will we added to the
* work queue after this is visible everywhere.
*/
pasid_state->invalid = true;
/* Make sure this is visible */
smp_wmb();
/* After this the device/pasid can't access the mm anymore */
amd_iommu_domain_clear_gcr3(domain, pasid_state->pasid); 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 */ /* Make sure no more pending faults are in the queue */
flush_workqueue(iommu_wq); flush_workqueue(iommu_wq);
@@ -573,7 +583,7 @@ static int ppr_notifier(struct notifier_block *nb, unsigned long e, void *data)
goto out; goto out;
pasid_state = get_pasid_state(dev_state, iommu_fault->pasid); pasid_state = get_pasid_state(dev_state, iommu_fault->pasid);
if (pasid_state == NULL) { if (pasid_state == NULL || pasid_state->invalid) {
/* We know the device but not the PASID -> send INVALID */ /* We know the device but not the PASID -> send INVALID */
amd_iommu_complete_ppr(dev_state->pdev, iommu_fault->pasid, amd_iommu_complete_ppr(dev_state->pdev, iommu_fault->pasid,
PPR_INVALID, tag); PPR_INVALID, tag);
@@ -657,6 +667,7 @@ int amd_iommu_bind_pasid(struct pci_dev *pdev, int pasid,
pasid_state->mm = get_task_mm(task); pasid_state->mm = get_task_mm(task);
pasid_state->device_state = dev_state; pasid_state->device_state = dev_state;
pasid_state->pasid = pasid; pasid_state->pasid = pasid;
pasid_state->invalid = false;
pasid_state->mn.ops = &iommu_mn; pasid_state->mn.ops = &iommu_mn;
if (pasid_state->mm == NULL) if (pasid_state->mm == NULL)
@@ -720,6 +731,9 @@ void amd_iommu_unbind_pasid(struct pci_dev *pdev, int pasid)
*/ */
put_pasid_state(pasid_state); put_pasid_state(pasid_state);
/* Clear the pasid state so that the pasid can be re-used */
clear_pasid_state(dev_state, pasid_state->pasid);
/* This will call the mn_release function and unbind the PASID */ /* This will call the mn_release function and unbind the PASID */
mmu_notifier_unregister(&pasid_state->mn, pasid_state->mm); mmu_notifier_unregister(&pasid_state->mn, pasid_state->mm);