lkml.org 
[lkml]   [2014]   [Jul]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 6/9] iommu/amd: Add pasid_state->invalid flag
Date
From: Joerg Roedel <jroedel@suse.de>

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>
---
drivers/iommu/amd_iommu_v2.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 6ba707b..69a46f1 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -53,6 +53,7 @@ struct pasid_state {
struct pri_queue pri[PRI_QUEUE_SIZE]; /* PRI tag states */
struct device_state *device_state; /* Link to our device_state */
int pasid; /* PASID index */
+ bool invalid; /* Used during teardown */
spinlock_t lock; /* Protect pri_queues and
mmu_notifer_count */
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;

+ /*
+ * 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);
- clear_pasid_state(pasid_state->device_state, pasid_state->pasid);

/* Make sure no more pending faults are in the queue */
flush_workqueue(iommu_wq);
@@ -573,7 +583,7 @@ static int ppr_notifier(struct notifier_block *nb, unsigned long e, void *data)
goto out;

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 */
amd_iommu_complete_ppr(dev_state->pdev, iommu_fault->pasid,
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->device_state = dev_state;
pasid_state->pasid = pasid;
+ pasid_state->invalid = false;
pasid_state->mn.ops = &iommu_mn;

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);

+ /* 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 */
mmu_notifier_unregister(&pasid_state->mn, pasid_state->mm);

--
1.7.9.5



\
 
 \ /
  Last update: 2014-07-11 00:21    [W:0.045 / U:0.172 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site