[PATCH 1/4] iommu/amd: Don't set pasid_state->mm to NULL in unbind_pasid

[PATCH 1/4] iommu/amd: Don't set pasid_state->mm to NULL in unbind_pasid

[Joerg Roedel]

From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>

With calling te mmu_notifier_register function we hold a
reference to the mm_struct that needs to be released in
mmu_notifier_unregister. This is true even if the notifier
was already unregistered from exit_mmap and the .release
call-back has already run.

So make sure we call mmu_notifier_unregister unconditionally
in amd_iommu_unbind_pasid.

Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
Tested-by: Oded Gabbay <oded.gabbay-5C7GfCeVMHo@public.gmane.org>
---
 drivers/iommu/amd_iommu_v2.c | 20 +++-----------------
 1 file changed, 3 insertions(+), 17 deletions(-)

diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index a195c78..2b7de88 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -320,13 +320,6 @@ static void unbind_pasid(struct pasid_state *pasid_state)
 
 	/* Make sure no more pending faults are in the queue */
 	flush_workqueue(iommu_wq);
-
-	/*
-	 * No more faults are in the work queue and no new faults will be queued
-	 * from here on. We can safely set pasid_state->mm to NULL now as the
-	 * mm_struct might go away after we return.
-	 */
-	pasid_state->mm = NULL;
 }
 
 static void free_pasid_states_level1(struct pasid_state **tbl)
@@ -756,17 +749,10 @@ void amd_iommu_unbind_pasid(struct pci_dev *pdev, int pasid)
 	clear_pasid_state(dev_state, pasid_state->pasid);
 
 	/*
-	 * Check if pasid_state->mm is still valid. If mn_release has already
-	 * run it will be NULL and we can't (and don't need to) call
-	 * mmu_notifier_unregister() on it anymore.
+	 * Call mmu_notifier_unregister to drop our reference
+	 * to pasid_state->mm
 	 */
-	if (pasid_state->mm) {
-		/*
-		 * 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);
 
 	put_pasid_state_wait(pasid_state); /* Reference taken in
 					      amd_iommu_pasid_bind */
-- 
1.9.1

[PATCH 2/4] iommu/amd: Remove change_pte mmu_notifier call-back

[Joerg Roedel]

From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>

All calls to this call-back are wrapped with
mmu_notifer_invalidate_range_start()/end(), making this
notifier pretty useless, so remove it.

Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
Tested-by: Oded Gabbay <oded.gabbay-5C7GfCeVMHo@public.gmane.org>
---
 drivers/iommu/amd_iommu_v2.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 2b7de88..524fd67 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -406,14 +406,6 @@ static int mn_clear_flush_young(struct mmu_notifier *mn,
 	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)
@@ -484,7 +476,6 @@ static void mn_release(struct mmu_notifier *mn, struct mm_struct *mm)
 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,
 	.invalidate_range_start = mn_invalidate_range_start,
 	.invalidate_range_end   = mn_invalidate_range_end,
-- 
1.9.1

[PATCH 3/4] iommu/amd: Fix device_state reference counting

[Joerg Roedel]

From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>

The references to the device state are not dropped
everywhere. This might cause a dead-lock in
amd_iommu_free_device(). Fix it.

Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
Tested-by: Oded Gabbay <oded.gabbay-5C7GfCeVMHo@public.gmane.org>
---
 drivers/iommu/amd_iommu_v2.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 524fd67..2de13be 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -368,6 +368,9 @@ static void free_pasid_states(struct device_state *dev_state)
 
 		put_pasid_state_wait(pasid_state); /* Reference taken in
 						      amd_iommu_pasid_bind */
+
+		/* Drop reference taken in amd_iommu_bind_pasid */
+		put_device_state(dev_state);
 	}
 
 	if (dev_state->pasid_levels == 2)
@@ -748,6 +751,10 @@ void amd_iommu_unbind_pasid(struct pci_dev *pdev, int pasid)
 	put_pasid_state_wait(pasid_state); /* Reference taken in
 					      amd_iommu_pasid_bind */
 out:
+	/* Drop reference taken in this function */
+	put_device_state(dev_state);
+
+	/* Drop reference taken in amd_iommu_bind_pasid */
 	put_device_state(dev_state);
 }
 EXPORT_SYMBOL(amd_iommu_unbind_pasid);
-- 
1.9.1

[PATCH 4/4] iommu/amd: Fix 2 typos in comments

[Joerg Roedel]

From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>

amd_iommu_pasid_bind -> amd_iommu_bind_pasid

Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
---
 drivers/iommu/amd_iommu_v2.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 2de13be..5f578e8 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -367,7 +367,7 @@ static void free_pasid_states(struct device_state *dev_state)
 		mmu_notifier_unregister(&pasid_state->mn, pasid_state->mm);
 
 		put_pasid_state_wait(pasid_state); /* Reference taken in
-						      amd_iommu_pasid_bind */
+						      amd_iommu_bind_pasid */
 
 		/* Drop reference taken in amd_iommu_bind_pasid */
 		put_device_state(dev_state);
@@ -749,7 +749,7 @@ void amd_iommu_unbind_pasid(struct pci_dev *pdev, int pasid)
 	mmu_notifier_unregister(&pasid_state->mn, pasid_state->mm);
 
 	put_pasid_state_wait(pasid_state); /* Reference taken in
-					      amd_iommu_pasid_bind */
+					      amd_iommu_bind_pasid */
 out:
 	/* Drop reference taken in this function */
 	put_device_state(dev_state);
-- 
1.9.1