[PATCH RESEND v10 0/4] iommu: Shared Virtual Addressing for SMMUv3 (PT sharing part)

[PATCH RESEND v10 0/4] iommu: Shared Virtual Addressing for SMMUv3 (PT sharing part)

[Jean-Philippe Brucker]

These are the remaining bits implementing iommu_sva_bind_device() for
SMMUv3. They didn't make it into v5.10 because an Ack was missing for
adding the PASID field to mm_struct. That is now upstream, in commit
52ad9bc64c74 ("mm: Add a pasid member to struct mm_struct"). No change
since last posting [1], only rebased onto v5.10-rc2.

Note that full SVA support for SMMUv3 still needs IOPF and DVM support,
coming soon.

[1] https://lore.kernel.org/linux-iommu/20200918101852.582559-1-jean-philippe@linaro.org/

Jean-Philippe Brucker (4):
  iommu/ioasid: Add ioasid references
  iommu/sva: Add PASID helpers
  iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind()
  iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops

 drivers/iommu/Kconfig                         |   7 +
 drivers/iommu/Makefile                        |   1 +
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  30 +++
 drivers/iommu/iommu-sva-lib.h                 |  15 ++
 include/linux/ioasid.h                        |  10 +-
 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   | 244 +++++++++++++++++-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   |  50 +++-
 drivers/iommu/intel/iommu.c                   |   4 +-
 drivers/iommu/intel/svm.c                     |   6 +-
 drivers/iommu/ioasid.c                        |  38 ++-
 drivers/iommu/iommu-sva-lib.c                 |  86 ++++++
 11 files changed, 468 insertions(+), 23 deletions(-)
 create mode 100644 drivers/iommu/iommu-sva-lib.h
 create mode 100644 drivers/iommu/iommu-sva-lib.c

-- 
2.29.1

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[PATCH RESEND v10 0/4] iommu: Shared Virtual Addressing for SMMUv3 (PT sharing part)

[Jean-Philippe Brucker]

These are the remaining bits implementing iommu_sva_bind_device() for
SMMUv3. They didn't make it into v5.10 because an Ack was missing for
adding the PASID field to mm_struct. That is now upstream, in commit
52ad9bc64c74 ("mm: Add a pasid member to struct mm_struct"). No change
since last posting [1], only rebased onto v5.10-rc2.

Note that full SVA support for SMMUv3 still needs IOPF and DVM support,
coming soon.

[1] https://lore.kernel.org/linux-iommu/20200918101852.582559-1-jean-philippe@linaro.org/

Jean-Philippe Brucker (4):
  iommu/ioasid: Add ioasid references
  iommu/sva: Add PASID helpers
  iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind()
  iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops

 drivers/iommu/Kconfig                         |   7 +
 drivers/iommu/Makefile                        |   1 +
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  30 +++
 drivers/iommu/iommu-sva-lib.h                 |  15 ++
 include/linux/ioasid.h                        |  10 +-
 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   | 244 +++++++++++++++++-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   |  50 +++-
 drivers/iommu/intel/iommu.c                   |   4 +-
 drivers/iommu/intel/svm.c                     |   6 +-
 drivers/iommu/ioasid.c                        |  38 ++-
 drivers/iommu/iommu-sva-lib.c                 |  86 ++++++
 11 files changed, 468 insertions(+), 23 deletions(-)
 create mode 100644 drivers/iommu/iommu-sva-lib.h
 create mode 100644 drivers/iommu/iommu-sva-lib.c

-- 
2.29.1


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[PATCH RESEND v10 1/4] iommu/ioasid: Add ioasid references

[Jean-Philippe Brucker]

Let IOASID users take references to existing ioasids with ioasid_get().
ioasid_put() drops a reference and only frees the ioasid when its
reference number is zero. It returns true if the ioasid was freed.
For drivers that don't call ioasid_get(), ioasid_put() is the same as
ioasid_free().

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
 include/linux/ioasid.h      | 10 ++++++++--
 drivers/iommu/intel/iommu.c |  4 ++--
 drivers/iommu/intel/svm.c   |  6 +++---
 drivers/iommu/ioasid.c      | 38 +++++++++++++++++++++++++++++++++----
 4 files changed, 47 insertions(+), 11 deletions(-)

diff --git a/include/linux/ioasid.h b/include/linux/ioasid.h
index 6f000d7a0ddc..e9dacd4b9f6b 100644
--- a/include/linux/ioasid.h
+++ b/include/linux/ioasid.h
@@ -34,7 +34,8 @@ struct ioasid_allocator_ops {
 #if IS_ENABLED(CONFIG_IOASID)
 ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
 		      void *private);
-void ioasid_free(ioasid_t ioasid);
+void ioasid_get(ioasid_t ioasid);
+bool ioasid_put(ioasid_t ioasid);
 void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid,
 		  bool (*getter)(void *));
 int ioasid_register_allocator(struct ioasid_allocator_ops *allocator);
@@ -48,10 +49,15 @@ static inline ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min,
 	return INVALID_IOASID;
 }
 
-static inline void ioasid_free(ioasid_t ioasid)
+static inline void ioasid_get(ioasid_t ioasid)
 {
 }
 
+static inline bool ioasid_put(ioasid_t ioasid)
+{
+	return false;
+}
+
 static inline void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid,
 				bool (*getter)(void *))
 {
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 8651f6d4dfa0..243d642142f1 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -5195,7 +5195,7 @@ static void auxiliary_unlink_device(struct dmar_domain *domain,
 	domain->auxd_refcnt--;
 
 	if (!domain->auxd_refcnt && domain->default_pasid > 0)
-		ioasid_free(domain->default_pasid);
+		ioasid_put(domain->default_pasid);
 }
 
 static int aux_domain_add_dev(struct dmar_domain *domain,
@@ -5256,7 +5256,7 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
 	spin_unlock(&iommu->lock);
 	spin_unlock_irqrestore(&device_domain_lock, flags);
 	if (!domain->auxd_refcnt && domain->default_pasid > 0)
-		ioasid_free(domain->default_pasid);
+		ioasid_put(domain->default_pasid);
 
 	return ret;
 }
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index f1861fa3d0e4..34f1914050f4 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -592,7 +592,7 @@ intel_svm_bind_mm(struct device *dev, unsigned int flags,
 		if (mm) {
 			ret = mmu_notifier_register(&svm->notifier, mm);
 			if (ret) {
-				ioasid_free(svm->pasid);
+				ioasid_put(svm->pasid);
 				kfree(svm);
 				kfree(sdev);
 				goto out;
@@ -610,7 +610,7 @@ intel_svm_bind_mm(struct device *dev, unsigned int flags,
 		if (ret) {
 			if (mm)
 				mmu_notifier_unregister(&svm->notifier, mm);
-			ioasid_free(svm->pasid);
+			ioasid_put(svm->pasid);
 			kfree(svm);
 			kfree(sdev);
 			goto out;
@@ -683,7 +683,7 @@ static int intel_svm_unbind_mm(struct device *dev, u32 pasid)
 			kfree_rcu(sdev, rcu);
 
 			if (list_empty(&svm->devs)) {
-				ioasid_free(svm->pasid);
+				ioasid_put(svm->pasid);
 				if (svm->mm) {
 					mmu_notifier_unregister(&svm->notifier, svm->mm);
 					/* Clear mm's pasid. */
diff --git a/drivers/iommu/ioasid.c b/drivers/iommu/ioasid.c
index 0f8dd377aada..50ee27bbd04e 100644
--- a/drivers/iommu/ioasid.c
+++ b/drivers/iommu/ioasid.c
@@ -2,7 +2,7 @@
 /*
  * I/O Address Space ID allocator. There is one global IOASID space, split into
  * subsets. Users create a subset with DECLARE_IOASID_SET, then allocate and
- * free IOASIDs with ioasid_alloc and ioasid_free.
+ * free IOASIDs with ioasid_alloc and ioasid_put.
  */
 #include <linux/ioasid.h>
 #include <linux/module.h>
@@ -15,6 +15,7 @@ struct ioasid_data {
 	struct ioasid_set *set;
 	void *private;
 	struct rcu_head rcu;
+	refcount_t refs;
 };
 
 /*
@@ -314,6 +315,7 @@ ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
 
 	data->set = set;
 	data->private = private;
+	refcount_set(&data->refs, 1);
 
 	/*
 	 * Custom allocator needs allocator data to perform platform specific
@@ -346,11 +348,34 @@ ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
 EXPORT_SYMBOL_GPL(ioasid_alloc);
 
 /**
- * ioasid_free - Free an IOASID
+ * ioasid_get - obtain a reference to the IOASID
+ */
+void ioasid_get(ioasid_t ioasid)
+{
+	struct ioasid_data *ioasid_data;
+
+	spin_lock(&ioasid_allocator_lock);
+	ioasid_data = xa_load(&active_allocator->xa, ioasid);
+	if (ioasid_data)
+		refcount_inc(&ioasid_data->refs);
+	else
+		WARN_ON(1);
+	spin_unlock(&ioasid_allocator_lock);
+}
+EXPORT_SYMBOL_GPL(ioasid_get);
+
+/**
+ * ioasid_put - Release a reference to an ioasid
  * @ioasid: the ID to remove
+ *
+ * Put a reference to the IOASID, free it when the number of references drops to
+ * zero.
+ *
+ * Return: %true if the IOASID was freed, %false otherwise.
  */
-void ioasid_free(ioasid_t ioasid)
+bool ioasid_put(ioasid_t ioasid)
 {
+	bool free = false;
 	struct ioasid_data *ioasid_data;
 
 	spin_lock(&ioasid_allocator_lock);
@@ -360,6 +385,10 @@ void ioasid_free(ioasid_t ioasid)
 		goto exit_unlock;
 	}
 
+	free = refcount_dec_and_test(&ioasid_data->refs);
+	if (!free)
+		goto exit_unlock;
+
 	active_allocator->ops->free(ioasid, active_allocator->ops->pdata);
 	/* Custom allocator needs additional steps to free the xa element */
 	if (active_allocator->flags & IOASID_ALLOCATOR_CUSTOM) {
@@ -369,8 +398,9 @@ void ioasid_free(ioasid_t ioasid)
 
 exit_unlock:
 	spin_unlock(&ioasid_allocator_lock);
+	return free;
 }
-EXPORT_SYMBOL_GPL(ioasid_free);
+EXPORT_SYMBOL_GPL(ioasid_put);
 
 /**
  * ioasid_find - Find IOASID data
-- 
2.29.1

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[PATCH RESEND v10 1/4] iommu/ioasid: Add ioasid references

[Jean-Philippe Brucker]

Let IOASID users take references to existing ioasids with ioasid_get().
ioasid_put() drops a reference and only frees the ioasid when its
reference number is zero. It returns true if the ioasid was freed.
For drivers that don't call ioasid_get(), ioasid_put() is the same as
ioasid_free().

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
 include/linux/ioasid.h      | 10 ++++++++--
 drivers/iommu/intel/iommu.c |  4 ++--
 drivers/iommu/intel/svm.c   |  6 +++---
 drivers/iommu/ioasid.c      | 38 +++++++++++++++++++++++++++++++++----
 4 files changed, 47 insertions(+), 11 deletions(-)

diff --git a/include/linux/ioasid.h b/include/linux/ioasid.h
index 6f000d7a0ddc..e9dacd4b9f6b 100644
--- a/include/linux/ioasid.h
+++ b/include/linux/ioasid.h
@@ -34,7 +34,8 @@ struct ioasid_allocator_ops {
 #if IS_ENABLED(CONFIG_IOASID)
 ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
 		      void *private);
-void ioasid_free(ioasid_t ioasid);
+void ioasid_get(ioasid_t ioasid);
+bool ioasid_put(ioasid_t ioasid);
 void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid,
 		  bool (*getter)(void *));
 int ioasid_register_allocator(struct ioasid_allocator_ops *allocator);
@@ -48,10 +49,15 @@ static inline ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min,
 	return INVALID_IOASID;
 }
 
-static inline void ioasid_free(ioasid_t ioasid)
+static inline void ioasid_get(ioasid_t ioasid)
 {
 }
 
+static inline bool ioasid_put(ioasid_t ioasid)
+{
+	return false;
+}
+
 static inline void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid,
 				bool (*getter)(void *))
 {
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 8651f6d4dfa0..243d642142f1 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -5195,7 +5195,7 @@ static void auxiliary_unlink_device(struct dmar_domain *domain,
 	domain->auxd_refcnt--;
 
 	if (!domain->auxd_refcnt && domain->default_pasid > 0)
-		ioasid_free(domain->default_pasid);
+		ioasid_put(domain->default_pasid);
 }
 
 static int aux_domain_add_dev(struct dmar_domain *domain,
@@ -5256,7 +5256,7 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
 	spin_unlock(&iommu->lock);
 	spin_unlock_irqrestore(&device_domain_lock, flags);
 	if (!domain->auxd_refcnt && domain->default_pasid > 0)
-		ioasid_free(domain->default_pasid);
+		ioasid_put(domain->default_pasid);
 
 	return ret;
 }
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index f1861fa3d0e4..34f1914050f4 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -592,7 +592,7 @@ intel_svm_bind_mm(struct device *dev, unsigned int flags,
 		if (mm) {
 			ret = mmu_notifier_register(&svm->notifier, mm);
 			if (ret) {
-				ioasid_free(svm->pasid);
+				ioasid_put(svm->pasid);
 				kfree(svm);
 				kfree(sdev);
 				goto out;
@@ -610,7 +610,7 @@ intel_svm_bind_mm(struct device *dev, unsigned int flags,
 		if (ret) {
 			if (mm)
 				mmu_notifier_unregister(&svm->notifier, mm);
-			ioasid_free(svm->pasid);
+			ioasid_put(svm->pasid);
 			kfree(svm);
 			kfree(sdev);
 			goto out;
@@ -683,7 +683,7 @@ static int intel_svm_unbind_mm(struct device *dev, u32 pasid)
 			kfree_rcu(sdev, rcu);
 
 			if (list_empty(&svm->devs)) {
-				ioasid_free(svm->pasid);
+				ioasid_put(svm->pasid);
 				if (svm->mm) {
 					mmu_notifier_unregister(&svm->notifier, svm->mm);
 					/* Clear mm's pasid. */
diff --git a/drivers/iommu/ioasid.c b/drivers/iommu/ioasid.c
index 0f8dd377aada..50ee27bbd04e 100644
--- a/drivers/iommu/ioasid.c
+++ b/drivers/iommu/ioasid.c
@@ -2,7 +2,7 @@
 /*
  * I/O Address Space ID allocator. There is one global IOASID space, split into
  * subsets. Users create a subset with DECLARE_IOASID_SET, then allocate and
- * free IOASIDs with ioasid_alloc and ioasid_free.
+ * free IOASIDs with ioasid_alloc and ioasid_put.
  */
 #include <linux/ioasid.h>
 #include <linux/module.h>
@@ -15,6 +15,7 @@ struct ioasid_data {
 	struct ioasid_set *set;
 	void *private;
 	struct rcu_head rcu;
+	refcount_t refs;
 };
 
 /*
@@ -314,6 +315,7 @@ ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
 
 	data->set = set;
 	data->private = private;
+	refcount_set(&data->refs, 1);
 
 	/*
 	 * Custom allocator needs allocator data to perform platform specific
@@ -346,11 +348,34 @@ ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
 EXPORT_SYMBOL_GPL(ioasid_alloc);
 
 /**
- * ioasid_free - Free an IOASID
+ * ioasid_get - obtain a reference to the IOASID
+ */
+void ioasid_get(ioasid_t ioasid)
+{
+	struct ioasid_data *ioasid_data;
+
+	spin_lock(&ioasid_allocator_lock);
+	ioasid_data = xa_load(&active_allocator->xa, ioasid);
+	if (ioasid_data)
+		refcount_inc(&ioasid_data->refs);
+	else
+		WARN_ON(1);
+	spin_unlock(&ioasid_allocator_lock);
+}
+EXPORT_SYMBOL_GPL(ioasid_get);
+
+/**
+ * ioasid_put - Release a reference to an ioasid
  * @ioasid: the ID to remove
+ *
+ * Put a reference to the IOASID, free it when the number of references drops to
+ * zero.
+ *
+ * Return: %true if the IOASID was freed, %false otherwise.
  */
-void ioasid_free(ioasid_t ioasid)
+bool ioasid_put(ioasid_t ioasid)
 {
+	bool free = false;
 	struct ioasid_data *ioasid_data;
 
 	spin_lock(&ioasid_allocator_lock);
@@ -360,6 +385,10 @@ void ioasid_free(ioasid_t ioasid)
 		goto exit_unlock;
 	}
 
+	free = refcount_dec_and_test(&ioasid_data->refs);
+	if (!free)
+		goto exit_unlock;
+
 	active_allocator->ops->free(ioasid, active_allocator->ops->pdata);
 	/* Custom allocator needs additional steps to free the xa element */
 	if (active_allocator->flags & IOASID_ALLOCATOR_CUSTOM) {
@@ -369,8 +398,9 @@ void ioasid_free(ioasid_t ioasid)
 
 exit_unlock:
 	spin_unlock(&ioasid_allocator_lock);
+	return free;
 }
-EXPORT_SYMBOL_GPL(ioasid_free);
+EXPORT_SYMBOL_GPL(ioasid_put);
 
 /**
  * ioasid_find - Find IOASID data
-- 
2.29.1


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[PATCH RESEND v10 2/4] iommu/sva: Add PASID helpers

[Jean-Philippe Brucker]

Let IOMMU drivers allocate a single PASID per mm. Store the mm in the
IOASID set to allow refcounting and searching mm by PASID, when handling
an I/O page fault.

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
 drivers/iommu/Kconfig         |  5 ++
 drivers/iommu/Makefile        |  1 +
 drivers/iommu/iommu-sva-lib.h | 15 ++++++
 drivers/iommu/iommu-sva-lib.c | 86 +++++++++++++++++++++++++++++++++++
 4 files changed, 107 insertions(+)
 create mode 100644 drivers/iommu/iommu-sva-lib.h
 create mode 100644 drivers/iommu/iommu-sva-lib.c

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 04878caf6da4..f5ebbdfbf636 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -103,6 +103,11 @@ config IOMMU_DMA
 	select IRQ_MSI_IOMMU
 	select NEED_SG_DMA_LENGTH
 
+# Shared Virtual Addressing library
+config IOMMU_SVA_LIB
+	bool
+	select IOASID
+
 config FSL_PAMU
 	bool "Freescale IOMMU support"
 	depends on PCI
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index 11f1771104f3..61bd30cd8369 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -27,3 +27,4 @@ obj-$(CONFIG_FSL_PAMU) += fsl_pamu.o fsl_pamu_domain.o
 obj-$(CONFIG_S390_IOMMU) += s390-iommu.o
 obj-$(CONFIG_HYPERV_IOMMU) += hyperv-iommu.o
 obj-$(CONFIG_VIRTIO_IOMMU) += virtio-iommu.o
+obj-$(CONFIG_IOMMU_SVA_LIB) += iommu-sva-lib.o
diff --git a/drivers/iommu/iommu-sva-lib.h b/drivers/iommu/iommu-sva-lib.h
new file mode 100644
index 000000000000..b40990aef3fd
--- /dev/null
+++ b/drivers/iommu/iommu-sva-lib.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * SVA library for IOMMU drivers
+ */
+#ifndef _IOMMU_SVA_LIB_H
+#define _IOMMU_SVA_LIB_H
+
+#include <linux/ioasid.h>
+#include <linux/mm_types.h>
+
+int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max);
+void iommu_sva_free_pasid(struct mm_struct *mm);
+struct mm_struct *iommu_sva_find(ioasid_t pasid);
+
+#endif /* _IOMMU_SVA_LIB_H */
diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c
new file mode 100644
index 000000000000..bd41405d34e9
--- /dev/null
+++ b/drivers/iommu/iommu-sva-lib.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Helpers for IOMMU drivers implementing SVA
+ */
+#include <linux/mutex.h>
+#include <linux/sched/mm.h>
+
+#include "iommu-sva-lib.h"
+
+static DEFINE_MUTEX(iommu_sva_lock);
+static DECLARE_IOASID_SET(iommu_sva_pasid);
+
+/**
+ * iommu_sva_alloc_pasid - Allocate a PASID for the mm
+ * @mm: the mm
+ * @min: minimum PASID value (inclusive)
+ * @max: maximum PASID value (inclusive)
+ *
+ * Try to allocate a PASID for this mm, or take a reference to the existing one
+ * provided it fits within the [@min, @max] range. On success the PASID is
+ * available in mm->pasid, and must be released with iommu_sva_free_pasid().
+ * @min must be greater than 0, because 0 indicates an unused mm->pasid.
+ *
+ * Returns 0 on success and < 0 on error.
+ */
+int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max)
+{
+	int ret = 0;
+	ioasid_t pasid;
+
+	if (min == INVALID_IOASID || max == INVALID_IOASID ||
+	    min == 0 || max < min)
+		return -EINVAL;
+
+	mutex_lock(&iommu_sva_lock);
+	if (mm->pasid) {
+		if (mm->pasid >= min && mm->pasid <= max)
+			ioasid_get(mm->pasid);
+		else
+			ret = -EOVERFLOW;
+	} else {
+		pasid = ioasid_alloc(&iommu_sva_pasid, min, max, mm);
+		if (pasid == INVALID_IOASID)
+			ret = -ENOMEM;
+		else
+			mm->pasid = pasid;
+	}
+	mutex_unlock(&iommu_sva_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_sva_alloc_pasid);
+
+/**
+ * iommu_sva_free_pasid - Release the mm's PASID
+ * @mm: the mm
+ *
+ * Drop one reference to a PASID allocated with iommu_sva_alloc_pasid()
+ */
+void iommu_sva_free_pasid(struct mm_struct *mm)
+{
+	mutex_lock(&iommu_sva_lock);
+	if (ioasid_put(mm->pasid))
+		mm->pasid = 0;
+	mutex_unlock(&iommu_sva_lock);
+}
+EXPORT_SYMBOL_GPL(iommu_sva_free_pasid);
+
+/* ioasid_find getter() requires a void * argument */
+static bool __mmget_not_zero(void *mm)
+{
+	return mmget_not_zero(mm);
+}
+
+/**
+ * iommu_sva_find() - Find mm associated to the given PASID
+ * @pasid: Process Address Space ID assigned to the mm
+ *
+ * On success a reference to the mm is taken, and must be released with mmput().
+ *
+ * Returns the mm corresponding to this PASID, or an error if not found.
+ */
+struct mm_struct *iommu_sva_find(ioasid_t pasid)
+{
+	return ioasid_find(&iommu_sva_pasid, pasid, __mmget_not_zero);
+}
+EXPORT_SYMBOL_GPL(iommu_sva_find);
-- 
2.29.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

[PATCH RESEND v10 2/4] iommu/sva: Add PASID helpers

[Jean-Philippe Brucker]

Let IOMMU drivers allocate a single PASID per mm. Store the mm in the
IOASID set to allow refcounting and searching mm by PASID, when handling
an I/O page fault.

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
 drivers/iommu/Kconfig         |  5 ++
 drivers/iommu/Makefile        |  1 +
 drivers/iommu/iommu-sva-lib.h | 15 ++++++
 drivers/iommu/iommu-sva-lib.c | 86 +++++++++++++++++++++++++++++++++++
 4 files changed, 107 insertions(+)
 create mode 100644 drivers/iommu/iommu-sva-lib.h
 create mode 100644 drivers/iommu/iommu-sva-lib.c

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 04878caf6da4..f5ebbdfbf636 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -103,6 +103,11 @@ config IOMMU_DMA
 	select IRQ_MSI_IOMMU
 	select NEED_SG_DMA_LENGTH
 
+# Shared Virtual Addressing library
+config IOMMU_SVA_LIB
+	bool
+	select IOASID
+
 config FSL_PAMU
 	bool "Freescale IOMMU support"
 	depends on PCI
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index 11f1771104f3..61bd30cd8369 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -27,3 +27,4 @@ obj-$(CONFIG_FSL_PAMU) += fsl_pamu.o fsl_pamu_domain.o
 obj-$(CONFIG_S390_IOMMU) += s390-iommu.o
 obj-$(CONFIG_HYPERV_IOMMU) += hyperv-iommu.o
 obj-$(CONFIG_VIRTIO_IOMMU) += virtio-iommu.o
+obj-$(CONFIG_IOMMU_SVA_LIB) += iommu-sva-lib.o
diff --git a/drivers/iommu/iommu-sva-lib.h b/drivers/iommu/iommu-sva-lib.h
new file mode 100644
index 000000000000..b40990aef3fd
--- /dev/null
+++ b/drivers/iommu/iommu-sva-lib.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * SVA library for IOMMU drivers
+ */
+#ifndef _IOMMU_SVA_LIB_H
+#define _IOMMU_SVA_LIB_H
+
+#include <linux/ioasid.h>
+#include <linux/mm_types.h>
+
+int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max);
+void iommu_sva_free_pasid(struct mm_struct *mm);
+struct mm_struct *iommu_sva_find(ioasid_t pasid);
+
+#endif /* _IOMMU_SVA_LIB_H */
diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c
new file mode 100644
index 000000000000..bd41405d34e9
--- /dev/null
+++ b/drivers/iommu/iommu-sva-lib.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Helpers for IOMMU drivers implementing SVA
+ */
+#include <linux/mutex.h>
+#include <linux/sched/mm.h>
+
+#include "iommu-sva-lib.h"
+
+static DEFINE_MUTEX(iommu_sva_lock);
+static DECLARE_IOASID_SET(iommu_sva_pasid);
+
+/**
+ * iommu_sva_alloc_pasid - Allocate a PASID for the mm
+ * @mm: the mm
+ * @min: minimum PASID value (inclusive)
+ * @max: maximum PASID value (inclusive)
+ *
+ * Try to allocate a PASID for this mm, or take a reference to the existing one
+ * provided it fits within the [@min, @max] range. On success the PASID is
+ * available in mm->pasid, and must be released with iommu_sva_free_pasid().
+ * @min must be greater than 0, because 0 indicates an unused mm->pasid.
+ *
+ * Returns 0 on success and < 0 on error.
+ */
+int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max)
+{
+	int ret = 0;
+	ioasid_t pasid;
+
+	if (min == INVALID_IOASID || max == INVALID_IOASID ||
+	    min == 0 || max < min)
+		return -EINVAL;
+
+	mutex_lock(&iommu_sva_lock);
+	if (mm->pasid) {
+		if (mm->pasid >= min && mm->pasid <= max)
+			ioasid_get(mm->pasid);
+		else
+			ret = -EOVERFLOW;
+	} else {
+		pasid = ioasid_alloc(&iommu_sva_pasid, min, max, mm);
+		if (pasid == INVALID_IOASID)
+			ret = -ENOMEM;
+		else
+			mm->pasid = pasid;
+	}
+	mutex_unlock(&iommu_sva_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_sva_alloc_pasid);
+
+/**
+ * iommu_sva_free_pasid - Release the mm's PASID
+ * @mm: the mm
+ *
+ * Drop one reference to a PASID allocated with iommu_sva_alloc_pasid()
+ */
+void iommu_sva_free_pasid(struct mm_struct *mm)
+{
+	mutex_lock(&iommu_sva_lock);
+	if (ioasid_put(mm->pasid))
+		mm->pasid = 0;
+	mutex_unlock(&iommu_sva_lock);
+}
+EXPORT_SYMBOL_GPL(iommu_sva_free_pasid);
+
+/* ioasid_find getter() requires a void * argument */
+static bool __mmget_not_zero(void *mm)
+{
+	return mmget_not_zero(mm);
+}
+
+/**
+ * iommu_sva_find() - Find mm associated to the given PASID
+ * @pasid: Process Address Space ID assigned to the mm
+ *
+ * On success a reference to the mm is taken, and must be released with mmput().
+ *
+ * Returns the mm corresponding to this PASID, or an error if not found.
+ */
+struct mm_struct *iommu_sva_find(ioasid_t pasid)
+{
+	return ioasid_find(&iommu_sva_pasid, pasid, __mmget_not_zero);
+}
+EXPORT_SYMBOL_GPL(iommu_sva_find);
-- 
2.29.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH RESEND v10 3/4] iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind()

[Jean-Philippe Brucker]

The sva_bind() function allows devices to access process address spaces
using a PASID (aka SSID).

(1) bind() allocates or gets an existing MMU notifier tied to the
    (domain, mm) pair. Each mm gets one PASID.

(2) Any change to the address space calls invalidate_range() which sends
    ATC invalidations (in a subsequent patch).

(3) When the process address space dies, the release() notifier disables
    the CD to allow reclaiming the page tables. Since release() has to
    be light we do not instruct device drivers to stop DMA here, we just
    ignore incoming page faults from this point onwards.

    To avoid any event 0x0a print (C_BAD_CD) we disable translation
    without clearing CD.V. PCIe Translation Requests and Page Requests
    are silently denied. Don't clear the R bit because the S bit can't
    be cleared when STALL_MODEL==0b10 (forced), and clearing R without
    clearing S is useless. Faulting transactions will stall and will be
    aborted by the IOPF handler.

(4) After stopping DMA, the device driver releases the bond by calling
    unbind(). We release the MMU notifier, free the PASID and the bond.

Three structures keep track of bonds:
* arm_smmu_bond: one per {device, mm} pair, the handle returned to the
  device driver for a bind() request.
* arm_smmu_mmu_notifier: one per {domain, mm} pair, deals with ATS/TLB
  invalidations and clearing the context descriptor on mm exit.
* arm_smmu_ctx_desc: one per mm, holds the pinned ASID and pgd.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
 drivers/iommu/Kconfig                         |   2 +
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  28 +++
 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   | 230 +++++++++++++++++-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   |  32 ++-
 4 files changed, 282 insertions(+), 10 deletions(-)

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index f5ebbdfbf636..192ef8f61310 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -316,6 +316,8 @@ config ARM_SMMU_V3
 config ARM_SMMU_V3_SVA
 	bool "Shared Virtual Addressing support for the ARM SMMUv3"
 	depends on ARM_SMMU_V3
+	select IOMMU_SVA_LIB
+	select MMU_NOTIFIER
 	help
 	  Support for sharing process address spaces with devices using the
 	  SMMUv3.
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index d4b7f40ccb02..e03ca01e0908 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -678,10 +678,18 @@ struct arm_smmu_domain {
 
 	struct list_head		devices;
 	spinlock_t			devices_lock;
+
+	struct list_head		mmu_notifiers;
 };
 
+static inline struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
+{
+	return container_of(dom, struct arm_smmu_domain, domain);
+}
+
 extern struct xarray arm_smmu_asid_xa;
 extern struct mutex arm_smmu_asid_lock;
+extern struct arm_smmu_ctx_desc quiet_cd;
 
 int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 			    struct arm_smmu_ctx_desc *cd);
@@ -694,6 +702,11 @@ bool arm_smmu_master_sva_supported(struct arm_smmu_master *master);
 bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master);
 int arm_smmu_master_enable_sva(struct arm_smmu_master *master);
 int arm_smmu_master_disable_sva(struct arm_smmu_master *master);
+struct iommu_sva *arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm,
+				    void *drvdata);
+void arm_smmu_sva_unbind(struct iommu_sva *handle);
+u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle);
+void arm_smmu_sva_notifier_synchronize(void);
 #else /* CONFIG_ARM_SMMU_V3_SVA */
 static inline bool arm_smmu_sva_supported(struct arm_smmu_device *smmu)
 {
@@ -719,5 +732,20 @@ static inline int arm_smmu_master_disable_sva(struct arm_smmu_master *master)
 {
 	return -ENODEV;
 }
+
+static inline struct iommu_sva *
+arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, void *drvdata)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+static inline void arm_smmu_sva_unbind(struct iommu_sva *handle) {}
+
+static inline u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle)
+{
+	return IOMMU_PASID_INVALID;
+}
+
+static inline void arm_smmu_sva_notifier_synchronize(void) {}
 #endif /* CONFIG_ARM_SMMU_V3_SVA */
 #endif /* _ARM_SMMU_V3_H */
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index 9255c9600fb8..4d03481289ff 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -5,11 +5,35 @@
 
 #include <linux/mm.h>
 #include <linux/mmu_context.h>
+#include <linux/mmu_notifier.h>
 #include <linux/slab.h>
 
 #include "arm-smmu-v3.h"
+#include "../../iommu-sva-lib.h"
 #include "../../io-pgtable-arm.h"
 
+struct arm_smmu_mmu_notifier {
+	struct mmu_notifier		mn;
+	struct arm_smmu_ctx_desc	*cd;
+	bool				cleared;
+	refcount_t			refs;
+	struct list_head		list;
+	struct arm_smmu_domain		*domain;
+};
+
+#define mn_to_smmu(mn) container_of(mn, struct arm_smmu_mmu_notifier, mn)
+
+struct arm_smmu_bond {
+	struct iommu_sva		sva;
+	struct mm_struct		*mm;
+	struct arm_smmu_mmu_notifier	*smmu_mn;
+	struct list_head		list;
+	refcount_t			refs;
+};
+
+#define sva_to_bond(handle) \
+	container_of(handle, struct arm_smmu_bond, sva)
+
 static DEFINE_MUTEX(sva_lock);
 
 /*
@@ -64,7 +88,6 @@ arm_smmu_share_asid(struct mm_struct *mm, u16 asid)
 	return NULL;
 }
 
-__maybe_unused
 static struct arm_smmu_ctx_desc *arm_smmu_alloc_shared_cd(struct mm_struct *mm)
 {
 	u16 asid;
@@ -145,7 +168,6 @@ static struct arm_smmu_ctx_desc *arm_smmu_alloc_shared_cd(struct mm_struct *mm)
 	return err < 0 ? ERR_PTR(err) : ret;
 }
 
-__maybe_unused
 static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd)
 {
 	if (arm_smmu_free_asid(cd)) {
@@ -155,6 +177,201 @@ static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd)
 	}
 }
 
+static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
+{
+	struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn);
+	struct arm_smmu_domain *smmu_domain = smmu_mn->domain;
+
+	mutex_lock(&sva_lock);
+	if (smmu_mn->cleared) {
+		mutex_unlock(&sva_lock);
+		return;
+	}
+
+	/*
+	 * DMA may still be running. Keep the cd valid to avoid C_BAD_CD events,
+	 * but disable translation.
+	 */
+	arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, &quiet_cd);
+
+	arm_smmu_tlb_inv_asid(smmu_domain->smmu, smmu_mn->cd->asid);
+
+	smmu_mn->cleared = true;
+	mutex_unlock(&sva_lock);
+}
+
+static void arm_smmu_mmu_notifier_free(struct mmu_notifier *mn)
+{
+	kfree(mn_to_smmu(mn));
+}
+
+static struct mmu_notifier_ops arm_smmu_mmu_notifier_ops = {
+	.release		= arm_smmu_mm_release,
+	.free_notifier		= arm_smmu_mmu_notifier_free,
+};
+
+/* Allocate or get existing MMU notifier for this {domain, mm} pair */
+static struct arm_smmu_mmu_notifier *
+arm_smmu_mmu_notifier_get(struct arm_smmu_domain *smmu_domain,
+			  struct mm_struct *mm)
+{
+	int ret;
+	struct arm_smmu_ctx_desc *cd;
+	struct arm_smmu_mmu_notifier *smmu_mn;
+
+	list_for_each_entry(smmu_mn, &smmu_domain->mmu_notifiers, list) {
+		if (smmu_mn->mn.mm == mm) {
+			refcount_inc(&smmu_mn->refs);
+			return smmu_mn;
+		}
+	}
+
+	cd = arm_smmu_alloc_shared_cd(mm);
+	if (IS_ERR(cd))
+		return ERR_CAST(cd);
+
+	smmu_mn = kzalloc(sizeof(*smmu_mn), GFP_KERNEL);
+	if (!smmu_mn) {
+		ret = -ENOMEM;
+		goto err_free_cd;
+	}
+
+	refcount_set(&smmu_mn->refs, 1);
+	smmu_mn->cd = cd;
+	smmu_mn->domain = smmu_domain;
+	smmu_mn->mn.ops = &arm_smmu_mmu_notifier_ops;
+
+	ret = mmu_notifier_register(&smmu_mn->mn, mm);
+	if (ret) {
+		kfree(smmu_mn);
+		goto err_free_cd;
+	}
+
+	ret = arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, cd);
+	if (ret)
+		goto err_put_notifier;
+
+	list_add(&smmu_mn->list, &smmu_domain->mmu_notifiers);
+	return smmu_mn;
+
+err_put_notifier:
+	/* Frees smmu_mn */
+	mmu_notifier_put(&smmu_mn->mn);
+err_free_cd:
+	arm_smmu_free_shared_cd(cd);
+	return ERR_PTR(ret);
+}
+
+static void arm_smmu_mmu_notifier_put(struct arm_smmu_mmu_notifier *smmu_mn)
+{
+	struct mm_struct *mm = smmu_mn->mn.mm;
+	struct arm_smmu_ctx_desc *cd = smmu_mn->cd;
+	struct arm_smmu_domain *smmu_domain = smmu_mn->domain;
+
+	if (!refcount_dec_and_test(&smmu_mn->refs))
+		return;
+
+	list_del(&smmu_mn->list);
+	arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, NULL);
+
+	/*
+	 * If we went through clear(), we've already invalidated, and no
+	 * new TLB entry can have been formed.
+	 */
+	if (!smmu_mn->cleared)
+		arm_smmu_tlb_inv_asid(smmu_domain->smmu, cd->asid);
+
+	/* Frees smmu_mn */
+	mmu_notifier_put(&smmu_mn->mn);
+	arm_smmu_free_shared_cd(cd);
+}
+
+static struct iommu_sva *
+__arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm)
+{
+	int ret;
+	struct arm_smmu_bond *bond;
+	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
+	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
+	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+
+	if (!master || !master->sva_enabled)
+		return ERR_PTR(-ENODEV);
+
+	/* If bind() was already called for this {dev, mm} pair, reuse it. */
+	list_for_each_entry(bond, &master->bonds, list) {
+		if (bond->mm == mm) {
+			refcount_inc(&bond->refs);
+			return &bond->sva;
+		}
+	}
+
+	bond = kzalloc(sizeof(*bond), GFP_KERNEL);
+	if (!bond)
+		return ERR_PTR(-ENOMEM);
+
+	/* Allocate a PASID for this mm if necessary */
+	ret = iommu_sva_alloc_pasid(mm, 1, (1U << master->ssid_bits) - 1);
+	if (ret)
+		goto err_free_bond;
+
+	bond->mm = mm;
+	bond->sva.dev = dev;
+	refcount_set(&bond->refs, 1);
+
+	bond->smmu_mn = arm_smmu_mmu_notifier_get(smmu_domain, mm);
+	if (IS_ERR(bond->smmu_mn)) {
+		ret = PTR_ERR(bond->smmu_mn);
+		goto err_free_pasid;
+	}
+
+	list_add(&bond->list, &master->bonds);
+	return &bond->sva;
+
+err_free_pasid:
+	iommu_sva_free_pasid(mm);
+err_free_bond:
+	kfree(bond);
+	return ERR_PTR(ret);
+}
+
+struct iommu_sva *
+arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, void *drvdata)
+{
+	struct iommu_sva *handle;
+	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
+	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+
+	if (smmu_domain->stage != ARM_SMMU_DOMAIN_S1)
+		return ERR_PTR(-EINVAL);
+
+	mutex_lock(&sva_lock);
+	handle = __arm_smmu_sva_bind(dev, mm);
+	mutex_unlock(&sva_lock);
+	return handle;
+}
+
+void arm_smmu_sva_unbind(struct iommu_sva *handle)
+{
+	struct arm_smmu_bond *bond = sva_to_bond(handle);
+
+	mutex_lock(&sva_lock);
+	if (refcount_dec_and_test(&bond->refs)) {
+		list_del(&bond->list);
+		arm_smmu_mmu_notifier_put(bond->smmu_mn);
+		iommu_sva_free_pasid(bond->mm);
+		kfree(bond);
+	}
+	mutex_unlock(&sva_lock);
+}
+
+u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle)
+{
+	struct arm_smmu_bond *bond = sva_to_bond(handle);
+
+	return bond->mm->pasid;
+}
+
 bool arm_smmu_sva_supported(struct arm_smmu_device *smmu)
 {
 	unsigned long reg, fld;
@@ -246,3 +463,12 @@ int arm_smmu_master_disable_sva(struct arm_smmu_master *master)
 
 	return 0;
 }
+
+void arm_smmu_sva_notifier_synchronize(void)
+{
+	/*
+	 * Some MMU notifiers may still be waiting to be freed, using
+	 * arm_smmu_mmu_notifier_free(). Wait for them.
+	 */
+	mmu_notifier_synchronize();
+}
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 61002f305a72..769845c34503 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -76,6 +76,12 @@ struct arm_smmu_option_prop {
 DEFINE_XARRAY_ALLOC1(arm_smmu_asid_xa);
 DEFINE_MUTEX(arm_smmu_asid_lock);
 
+/*
+ * Special value used by SVA when a process dies, to quiesce a CD without
+ * disabling it.
+ */
+struct arm_smmu_ctx_desc quiet_cd = { 0 };
+
 static struct arm_smmu_option_prop arm_smmu_options[] = {
 	{ ARM_SMMU_OPT_SKIP_PREFETCH, "hisilicon,broken-prefetch-cmd" },
 	{ ARM_SMMU_OPT_PAGE0_REGS_ONLY, "cavium,cn9900-broken-page1-regspace"},
@@ -91,11 +97,6 @@ static inline void __iomem *arm_smmu_page1_fixup(unsigned long offset,
 	return smmu->base + offset;
 }
 
-static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
-{
-	return container_of(dom, struct arm_smmu_domain, domain);
-}
-
 static void parse_driver_options(struct arm_smmu_device *smmu)
 {
 	int i = 0;
@@ -983,7 +984,9 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 	 * (2) Install a secondary CD, for SID+SSID traffic.
 	 * (3) Update ASID of a CD. Atomically write the first 64 bits of the
 	 *     CD, then invalidate the old entry and mappings.
-	 * (4) Remove a secondary CD.
+	 * (4) Quiesce the context without clearing the valid bit. Disable
+	 *     translation, and ignore any translation fault.
+	 * (5) Remove a secondary CD.
 	 */
 	u64 val;
 	bool cd_live;
@@ -1000,8 +1003,10 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 	val = le64_to_cpu(cdptr[0]);
 	cd_live = !!(val & CTXDESC_CD_0_V);
 
-	if (!cd) { /* (4) */
+	if (!cd) { /* (5) */
 		val = 0;
+	} else if (cd == &quiet_cd) { /* (4) */
+		val |= CTXDESC_CD_0_TCR_EPD0;
 	} else if (cd_live) { /* (3) */
 		val &= ~CTXDESC_CD_0_ASID;
 		val |= FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid);
@@ -1794,6 +1799,7 @@ static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
 	mutex_init(&smmu_domain->init_mutex);
 	INIT_LIST_HEAD(&smmu_domain->devices);
 	spin_lock_init(&smmu_domain->devices_lock);
+	INIT_LIST_HEAD(&smmu_domain->mmu_notifiers);
 
 	return &smmu_domain->domain;
 }
@@ -2585,6 +2591,9 @@ static struct iommu_ops arm_smmu_ops = {
 	.dev_feat_enabled	= arm_smmu_dev_feature_enabled,
 	.dev_enable_feat	= arm_smmu_dev_enable_feature,
 	.dev_disable_feat	= arm_smmu_dev_disable_feature,
+	.sva_bind		= arm_smmu_sva_bind,
+	.sva_unbind		= arm_smmu_sva_unbind,
+	.sva_get_pasid		= arm_smmu_sva_get_pasid,
 	.pgsize_bitmap		= -1UL, /* Restricted during device attach */
 };
 
@@ -3607,6 +3616,12 @@ static const struct of_device_id arm_smmu_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
 
+static void arm_smmu_driver_unregister(struct platform_driver *drv)
+{
+	arm_smmu_sva_notifier_synchronize();
+	platform_driver_unregister(drv);
+}
+
 static struct platform_driver arm_smmu_driver = {
 	.driver	= {
 		.name			= "arm-smmu-v3",
@@ -3617,7 +3632,8 @@ static struct platform_driver arm_smmu_driver = {
 	.remove	= arm_smmu_device_remove,
 	.shutdown = arm_smmu_device_shutdown,
 };
-module_platform_driver(arm_smmu_driver);
+module_driver(arm_smmu_driver, platform_driver_register,
+	      arm_smmu_driver_unregister);
 
 MODULE_DESCRIPTION("IOMMU API for ARM architected SMMUv3 implementations");
 MODULE_AUTHOR("Will Deacon <will@kernel.org>");
-- 
2.29.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

[PATCH RESEND v10 3/4] iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind()

[Jean-Philippe Brucker]

The sva_bind() function allows devices to access process address spaces
using a PASID (aka SSID).

(1) bind() allocates or gets an existing MMU notifier tied to the
    (domain, mm) pair. Each mm gets one PASID.

(2) Any change to the address space calls invalidate_range() which sends
    ATC invalidations (in a subsequent patch).

(3) When the process address space dies, the release() notifier disables
    the CD to allow reclaiming the page tables. Since release() has to
    be light we do not instruct device drivers to stop DMA here, we just
    ignore incoming page faults from this point onwards.

    To avoid any event 0x0a print (C_BAD_CD) we disable translation
    without clearing CD.V. PCIe Translation Requests and Page Requests
    are silently denied. Don't clear the R bit because the S bit can't
    be cleared when STALL_MODEL==0b10 (forced), and clearing R without
    clearing S is useless. Faulting transactions will stall and will be
    aborted by the IOPF handler.

(4) After stopping DMA, the device driver releases the bond by calling
    unbind(). We release the MMU notifier, free the PASID and the bond.

Three structures keep track of bonds:
* arm_smmu_bond: one per {device, mm} pair, the handle returned to the
  device driver for a bind() request.
* arm_smmu_mmu_notifier: one per {domain, mm} pair, deals with ATS/TLB
  invalidations and clearing the context descriptor on mm exit.
* arm_smmu_ctx_desc: one per mm, holds the pinned ASID and pgd.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
 drivers/iommu/Kconfig                         |   2 +
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  28 +++
 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   | 230 +++++++++++++++++-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   |  32 ++-
 4 files changed, 282 insertions(+), 10 deletions(-)

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index f5ebbdfbf636..192ef8f61310 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -316,6 +316,8 @@ config ARM_SMMU_V3
 config ARM_SMMU_V3_SVA
 	bool "Shared Virtual Addressing support for the ARM SMMUv3"
 	depends on ARM_SMMU_V3
+	select IOMMU_SVA_LIB
+	select MMU_NOTIFIER
 	help
 	  Support for sharing process address spaces with devices using the
 	  SMMUv3.
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index d4b7f40ccb02..e03ca01e0908 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -678,10 +678,18 @@ struct arm_smmu_domain {
 
 	struct list_head		devices;
 	spinlock_t			devices_lock;
+
+	struct list_head		mmu_notifiers;
 };
 
+static inline struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
+{
+	return container_of(dom, struct arm_smmu_domain, domain);
+}
+
 extern struct xarray arm_smmu_asid_xa;
 extern struct mutex arm_smmu_asid_lock;
+extern struct arm_smmu_ctx_desc quiet_cd;
 
 int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 			    struct arm_smmu_ctx_desc *cd);
@@ -694,6 +702,11 @@ bool arm_smmu_master_sva_supported(struct arm_smmu_master *master);
 bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master);
 int arm_smmu_master_enable_sva(struct arm_smmu_master *master);
 int arm_smmu_master_disable_sva(struct arm_smmu_master *master);
+struct iommu_sva *arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm,
+				    void *drvdata);
+void arm_smmu_sva_unbind(struct iommu_sva *handle);
+u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle);
+void arm_smmu_sva_notifier_synchronize(void);
 #else /* CONFIG_ARM_SMMU_V3_SVA */
 static inline bool arm_smmu_sva_supported(struct arm_smmu_device *smmu)
 {
@@ -719,5 +732,20 @@ static inline int arm_smmu_master_disable_sva(struct arm_smmu_master *master)
 {
 	return -ENODEV;
 }
+
+static inline struct iommu_sva *
+arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, void *drvdata)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+static inline void arm_smmu_sva_unbind(struct iommu_sva *handle) {}
+
+static inline u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle)
+{
+	return IOMMU_PASID_INVALID;
+}
+
+static inline void arm_smmu_sva_notifier_synchronize(void) {}
 #endif /* CONFIG_ARM_SMMU_V3_SVA */
 #endif /* _ARM_SMMU_V3_H */
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index 9255c9600fb8..4d03481289ff 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -5,11 +5,35 @@
 
 #include <linux/mm.h>
 #include <linux/mmu_context.h>
+#include <linux/mmu_notifier.h>
 #include <linux/slab.h>
 
 #include "arm-smmu-v3.h"
+#include "../../iommu-sva-lib.h"
 #include "../../io-pgtable-arm.h"
 
+struct arm_smmu_mmu_notifier {
+	struct mmu_notifier		mn;
+	struct arm_smmu_ctx_desc	*cd;
+	bool				cleared;
+	refcount_t			refs;
+	struct list_head		list;
+	struct arm_smmu_domain		*domain;
+};
+
+#define mn_to_smmu(mn) container_of(mn, struct arm_smmu_mmu_notifier, mn)
+
+struct arm_smmu_bond {
+	struct iommu_sva		sva;
+	struct mm_struct		*mm;
+	struct arm_smmu_mmu_notifier	*smmu_mn;
+	struct list_head		list;
+	refcount_t			refs;
+};
+
+#define sva_to_bond(handle) \
+	container_of(handle, struct arm_smmu_bond, sva)
+
 static DEFINE_MUTEX(sva_lock);
 
 /*
@@ -64,7 +88,6 @@ arm_smmu_share_asid(struct mm_struct *mm, u16 asid)
 	return NULL;
 }
 
-__maybe_unused
 static struct arm_smmu_ctx_desc *arm_smmu_alloc_shared_cd(struct mm_struct *mm)
 {
 	u16 asid;
@@ -145,7 +168,6 @@ static struct arm_smmu_ctx_desc *arm_smmu_alloc_shared_cd(struct mm_struct *mm)
 	return err < 0 ? ERR_PTR(err) : ret;
 }
 
-__maybe_unused
 static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd)
 {
 	if (arm_smmu_free_asid(cd)) {
@@ -155,6 +177,201 @@ static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd)
 	}
 }
 
+static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
+{
+	struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn);
+	struct arm_smmu_domain *smmu_domain = smmu_mn->domain;
+
+	mutex_lock(&sva_lock);
+	if (smmu_mn->cleared) {
+		mutex_unlock(&sva_lock);
+		return;
+	}
+
+	/*
+	 * DMA may still be running. Keep the cd valid to avoid C_BAD_CD events,
+	 * but disable translation.
+	 */
+	arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, &quiet_cd);
+
+	arm_smmu_tlb_inv_asid(smmu_domain->smmu, smmu_mn->cd->asid);
+
+	smmu_mn->cleared = true;
+	mutex_unlock(&sva_lock);
+}
+
+static void arm_smmu_mmu_notifier_free(struct mmu_notifier *mn)
+{
+	kfree(mn_to_smmu(mn));
+}
+
+static struct mmu_notifier_ops arm_smmu_mmu_notifier_ops = {
+	.release		= arm_smmu_mm_release,
+	.free_notifier		= arm_smmu_mmu_notifier_free,
+};
+
+/* Allocate or get existing MMU notifier for this {domain, mm} pair */
+static struct arm_smmu_mmu_notifier *
+arm_smmu_mmu_notifier_get(struct arm_smmu_domain *smmu_domain,
+			  struct mm_struct *mm)
+{
+	int ret;
+	struct arm_smmu_ctx_desc *cd;
+	struct arm_smmu_mmu_notifier *smmu_mn;
+
+	list_for_each_entry(smmu_mn, &smmu_domain->mmu_notifiers, list) {
+		if (smmu_mn->mn.mm == mm) {
+			refcount_inc(&smmu_mn->refs);
+			return smmu_mn;
+		}
+	}
+
+	cd = arm_smmu_alloc_shared_cd(mm);
+	if (IS_ERR(cd))
+		return ERR_CAST(cd);
+
+	smmu_mn = kzalloc(sizeof(*smmu_mn), GFP_KERNEL);
+	if (!smmu_mn) {
+		ret = -ENOMEM;
+		goto err_free_cd;
+	}
+
+	refcount_set(&smmu_mn->refs, 1);
+	smmu_mn->cd = cd;
+	smmu_mn->domain = smmu_domain;
+	smmu_mn->mn.ops = &arm_smmu_mmu_notifier_ops;
+
+	ret = mmu_notifier_register(&smmu_mn->mn, mm);
+	if (ret) {
+		kfree(smmu_mn);
+		goto err_free_cd;
+	}
+
+	ret = arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, cd);
+	if (ret)
+		goto err_put_notifier;
+
+	list_add(&smmu_mn->list, &smmu_domain->mmu_notifiers);
+	return smmu_mn;
+
+err_put_notifier:
+	/* Frees smmu_mn */
+	mmu_notifier_put(&smmu_mn->mn);
+err_free_cd:
+	arm_smmu_free_shared_cd(cd);
+	return ERR_PTR(ret);
+}
+
+static void arm_smmu_mmu_notifier_put(struct arm_smmu_mmu_notifier *smmu_mn)
+{
+	struct mm_struct *mm = smmu_mn->mn.mm;
+	struct arm_smmu_ctx_desc *cd = smmu_mn->cd;
+	struct arm_smmu_domain *smmu_domain = smmu_mn->domain;
+
+	if (!refcount_dec_and_test(&smmu_mn->refs))
+		return;
+
+	list_del(&smmu_mn->list);
+	arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, NULL);
+
+	/*
+	 * If we went through clear(), we've already invalidated, and no
+	 * new TLB entry can have been formed.
+	 */
+	if (!smmu_mn->cleared)
+		arm_smmu_tlb_inv_asid(smmu_domain->smmu, cd->asid);
+
+	/* Frees smmu_mn */
+	mmu_notifier_put(&smmu_mn->mn);
+	arm_smmu_free_shared_cd(cd);
+}
+
+static struct iommu_sva *
+__arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm)
+{
+	int ret;
+	struct arm_smmu_bond *bond;
+	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
+	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
+	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+
+	if (!master || !master->sva_enabled)
+		return ERR_PTR(-ENODEV);
+
+	/* If bind() was already called for this {dev, mm} pair, reuse it. */
+	list_for_each_entry(bond, &master->bonds, list) {
+		if (bond->mm == mm) {
+			refcount_inc(&bond->refs);
+			return &bond->sva;
+		}
+	}
+
+	bond = kzalloc(sizeof(*bond), GFP_KERNEL);
+	if (!bond)
+		return ERR_PTR(-ENOMEM);
+
+	/* Allocate a PASID for this mm if necessary */
+	ret = iommu_sva_alloc_pasid(mm, 1, (1U << master->ssid_bits) - 1);
+	if (ret)
+		goto err_free_bond;
+
+	bond->mm = mm;
+	bond->sva.dev = dev;
+	refcount_set(&bond->refs, 1);
+
+	bond->smmu_mn = arm_smmu_mmu_notifier_get(smmu_domain, mm);
+	if (IS_ERR(bond->smmu_mn)) {
+		ret = PTR_ERR(bond->smmu_mn);
+		goto err_free_pasid;
+	}
+
+	list_add(&bond->list, &master->bonds);
+	return &bond->sva;
+
+err_free_pasid:
+	iommu_sva_free_pasid(mm);
+err_free_bond:
+	kfree(bond);
+	return ERR_PTR(ret);
+}
+
+struct iommu_sva *
+arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, void *drvdata)
+{
+	struct iommu_sva *handle;
+	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
+	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+
+	if (smmu_domain->stage != ARM_SMMU_DOMAIN_S1)
+		return ERR_PTR(-EINVAL);
+
+	mutex_lock(&sva_lock);
+	handle = __arm_smmu_sva_bind(dev, mm);
+	mutex_unlock(&sva_lock);
+	return handle;
+}
+
+void arm_smmu_sva_unbind(struct iommu_sva *handle)
+{
+	struct arm_smmu_bond *bond = sva_to_bond(handle);
+
+	mutex_lock(&sva_lock);
+	if (refcount_dec_and_test(&bond->refs)) {
+		list_del(&bond->list);
+		arm_smmu_mmu_notifier_put(bond->smmu_mn);
+		iommu_sva_free_pasid(bond->mm);
+		kfree(bond);
+	}
+	mutex_unlock(&sva_lock);
+}
+
+u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle)
+{
+	struct arm_smmu_bond *bond = sva_to_bond(handle);
+
+	return bond->mm->pasid;
+}
+
 bool arm_smmu_sva_supported(struct arm_smmu_device *smmu)
 {
 	unsigned long reg, fld;
@@ -246,3 +463,12 @@ int arm_smmu_master_disable_sva(struct arm_smmu_master *master)
 
 	return 0;
 }
+
+void arm_smmu_sva_notifier_synchronize(void)
+{
+	/*
+	 * Some MMU notifiers may still be waiting to be freed, using
+	 * arm_smmu_mmu_notifier_free(). Wait for them.
+	 */
+	mmu_notifier_synchronize();
+}
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 61002f305a72..769845c34503 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -76,6 +76,12 @@ struct arm_smmu_option_prop {
 DEFINE_XARRAY_ALLOC1(arm_smmu_asid_xa);
 DEFINE_MUTEX(arm_smmu_asid_lock);
 
+/*
+ * Special value used by SVA when a process dies, to quiesce a CD without
+ * disabling it.
+ */
+struct arm_smmu_ctx_desc quiet_cd = { 0 };
+
 static struct arm_smmu_option_prop arm_smmu_options[] = {
 	{ ARM_SMMU_OPT_SKIP_PREFETCH, "hisilicon,broken-prefetch-cmd" },
 	{ ARM_SMMU_OPT_PAGE0_REGS_ONLY, "cavium,cn9900-broken-page1-regspace"},
@@ -91,11 +97,6 @@ static inline void __iomem *arm_smmu_page1_fixup(unsigned long offset,
 	return smmu->base + offset;
 }
 
-static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
-{
-	return container_of(dom, struct arm_smmu_domain, domain);
-}
-
 static void parse_driver_options(struct arm_smmu_device *smmu)
 {
 	int i = 0;
@@ -983,7 +984,9 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 	 * (2) Install a secondary CD, for SID+SSID traffic.
 	 * (3) Update ASID of a CD. Atomically write the first 64 bits of the
 	 *     CD, then invalidate the old entry and mappings.
-	 * (4) Remove a secondary CD.
+	 * (4) Quiesce the context without clearing the valid bit. Disable
+	 *     translation, and ignore any translation fault.
+	 * (5) Remove a secondary CD.
 	 */
 	u64 val;
 	bool cd_live;
@@ -1000,8 +1003,10 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 	val = le64_to_cpu(cdptr[0]);
 	cd_live = !!(val & CTXDESC_CD_0_V);
 
-	if (!cd) { /* (4) */
+	if (!cd) { /* (5) */
 		val = 0;
+	} else if (cd == &quiet_cd) { /* (4) */
+		val |= CTXDESC_CD_0_TCR_EPD0;
 	} else if (cd_live) { /* (3) */
 		val &= ~CTXDESC_CD_0_ASID;
 		val |= FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid);
@@ -1794,6 +1799,7 @@ static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
 	mutex_init(&smmu_domain->init_mutex);
 	INIT_LIST_HEAD(&smmu_domain->devices);
 	spin_lock_init(&smmu_domain->devices_lock);
+	INIT_LIST_HEAD(&smmu_domain->mmu_notifiers);
 
 	return &smmu_domain->domain;
 }
@@ -2585,6 +2591,9 @@ static struct iommu_ops arm_smmu_ops = {
 	.dev_feat_enabled	= arm_smmu_dev_feature_enabled,
 	.dev_enable_feat	= arm_smmu_dev_enable_feature,
 	.dev_disable_feat	= arm_smmu_dev_disable_feature,
+	.sva_bind		= arm_smmu_sva_bind,
+	.sva_unbind		= arm_smmu_sva_unbind,
+	.sva_get_pasid		= arm_smmu_sva_get_pasid,
 	.pgsize_bitmap		= -1UL, /* Restricted during device attach */
 };
 
@@ -3607,6 +3616,12 @@ static const struct of_device_id arm_smmu_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
 
+static void arm_smmu_driver_unregister(struct platform_driver *drv)
+{
+	arm_smmu_sva_notifier_synchronize();
+	platform_driver_unregister(drv);
+}
+
 static struct platform_driver arm_smmu_driver = {
 	.driver	= {
 		.name			= "arm-smmu-v3",
@@ -3617,7 +3632,8 @@ static struct platform_driver arm_smmu_driver = {
 	.remove	= arm_smmu_device_remove,
 	.shutdown = arm_smmu_device_shutdown,
 };
-module_platform_driver(arm_smmu_driver);
+module_driver(arm_smmu_driver, platform_driver_register,
+	      arm_smmu_driver_unregister);
 
 MODULE_DESCRIPTION("IOMMU API for ARM architected SMMUv3 implementations");
 MODULE_AUTHOR("Will Deacon <will@kernel.org>");
-- 
2.29.1


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[PATCH RESEND v10 4/4] iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops

[Jean-Philippe Brucker]

The invalidate_range() notifier is called for any change to the address
space. Perform the required ATC invalidations.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h    |  2 ++
 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c    | 16 +++++++++++++++-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c    | 18 ++++++++++++++++--
 3 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index e03ca01e0908..96c2e9565e00 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -695,6 +695,8 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 			    struct arm_smmu_ctx_desc *cd);
 void arm_smmu_tlb_inv_asid(struct arm_smmu_device *smmu, u16 asid);
 bool arm_smmu_free_asid(struct arm_smmu_ctx_desc *cd);
+int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain, int ssid,
+			    unsigned long iova, size_t size);
 
 #ifdef CONFIG_ARM_SMMU_V3_SVA
 bool arm_smmu_sva_supported(struct arm_smmu_device *smmu);
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index 4d03481289ff..e13b092e6004 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -177,6 +177,16 @@ static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd)
 	}
 }
 
+static void arm_smmu_mm_invalidate_range(struct mmu_notifier *mn,
+					 struct mm_struct *mm,
+					 unsigned long start, unsigned long end)
+{
+	struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn);
+
+	arm_smmu_atc_inv_domain(smmu_mn->domain, mm->pasid, start,
+				end - start + 1);
+}
+
 static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
 {
 	struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn);
@@ -195,6 +205,7 @@ static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
 	arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, &quiet_cd);
 
 	arm_smmu_tlb_inv_asid(smmu_domain->smmu, smmu_mn->cd->asid);
+	arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0);
 
 	smmu_mn->cleared = true;
 	mutex_unlock(&sva_lock);
@@ -206,6 +217,7 @@ static void arm_smmu_mmu_notifier_free(struct mmu_notifier *mn)
 }
 
 static struct mmu_notifier_ops arm_smmu_mmu_notifier_ops = {
+	.invalidate_range	= arm_smmu_mm_invalidate_range,
 	.release		= arm_smmu_mm_release,
 	.free_notifier		= arm_smmu_mmu_notifier_free,
 };
@@ -278,8 +290,10 @@ static void arm_smmu_mmu_notifier_put(struct arm_smmu_mmu_notifier *smmu_mn)
 	 * If we went through clear(), we've already invalidated, and no
 	 * new TLB entry can have been formed.
 	 */
-	if (!smmu_mn->cleared)
+	if (!smmu_mn->cleared) {
 		arm_smmu_tlb_inv_asid(smmu_domain->smmu, cd->asid);
+		arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0);
+	}
 
 	/* Frees smmu_mn */
 	mmu_notifier_put(&smmu_mn->mn);
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 769845c34503..73c26e68e12e 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1524,6 +1524,20 @@ arm_smmu_atc_inv_to_cmd(int ssid, unsigned long iova, size_t size,
 	size_t inval_grain_shift = 12;
 	unsigned long page_start, page_end;
 
+	/*
+	 * ATS and PASID:
+	 *
+	 * If substream_valid is clear, the PCIe TLP is sent without a PASID
+	 * prefix. In that case all ATC entries within the address range are
+	 * invalidated, including those that were requested with a PASID! There
+	 * is no way to invalidate only entries without PASID.
+	 *
+	 * When using STRTAB_STE_1_S1DSS_SSID0 (reserving CD 0 for non-PASID
+	 * traffic), translation requests without PASID create ATC entries
+	 * without PASID, which must be invalidated with substream_valid clear.
+	 * This has the unpleasant side-effect of invalidating all PASID-tagged
+	 * ATC entries within the address range.
+	 */
 	*cmd = (struct arm_smmu_cmdq_ent) {
 		.opcode			= CMDQ_OP_ATC_INV,
 		.substream_valid	= !!ssid,
@@ -1582,8 +1596,8 @@ static int arm_smmu_atc_inv_master(struct arm_smmu_master *master)
 	return arm_smmu_cmdq_issue_sync(master->smmu);
 }
 
-static int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain,
-				   int ssid, unsigned long iova, size_t size)
+int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain, int ssid,
+			    unsigned long iova, size_t size)
 {
 	int i;
 	unsigned long flags;
-- 
2.29.1

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https://lists.linuxfoundation.org/mailman/listinfo/iommu

[PATCH RESEND v10 4/4] iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops

[Jean-Philippe Brucker]

The invalidate_range() notifier is called for any change to the address
space. Perform the required ATC invalidations.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h    |  2 ++
 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c    | 16 +++++++++++++++-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c    | 18 ++++++++++++++++--
 3 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index e03ca01e0908..96c2e9565e00 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -695,6 +695,8 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 			    struct arm_smmu_ctx_desc *cd);
 void arm_smmu_tlb_inv_asid(struct arm_smmu_device *smmu, u16 asid);
 bool arm_smmu_free_asid(struct arm_smmu_ctx_desc *cd);
+int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain, int ssid,
+			    unsigned long iova, size_t size);
 
 #ifdef CONFIG_ARM_SMMU_V3_SVA
 bool arm_smmu_sva_supported(struct arm_smmu_device *smmu);
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index 4d03481289ff..e13b092e6004 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -177,6 +177,16 @@ static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd)
 	}
 }
 
+static void arm_smmu_mm_invalidate_range(struct mmu_notifier *mn,
+					 struct mm_struct *mm,
+					 unsigned long start, unsigned long end)
+{
+	struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn);
+
+	arm_smmu_atc_inv_domain(smmu_mn->domain, mm->pasid, start,
+				end - start + 1);
+}
+
 static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
 {
 	struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn);
@@ -195,6 +205,7 @@ static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
 	arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, &quiet_cd);
 
 	arm_smmu_tlb_inv_asid(smmu_domain->smmu, smmu_mn->cd->asid);
+	arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0);
 
 	smmu_mn->cleared = true;
 	mutex_unlock(&sva_lock);
@@ -206,6 +217,7 @@ static void arm_smmu_mmu_notifier_free(struct mmu_notifier *mn)
 }
 
 static struct mmu_notifier_ops arm_smmu_mmu_notifier_ops = {
+	.invalidate_range	= arm_smmu_mm_invalidate_range,
 	.release		= arm_smmu_mm_release,
 	.free_notifier		= arm_smmu_mmu_notifier_free,
 };
@@ -278,8 +290,10 @@ static void arm_smmu_mmu_notifier_put(struct arm_smmu_mmu_notifier *smmu_mn)
 	 * If we went through clear(), we've already invalidated, and no
 	 * new TLB entry can have been formed.
 	 */
-	if (!smmu_mn->cleared)
+	if (!smmu_mn->cleared) {
 		arm_smmu_tlb_inv_asid(smmu_domain->smmu, cd->asid);
+		arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0);
+	}
 
 	/* Frees smmu_mn */
 	mmu_notifier_put(&smmu_mn->mn);
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 769845c34503..73c26e68e12e 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1524,6 +1524,20 @@ arm_smmu_atc_inv_to_cmd(int ssid, unsigned long iova, size_t size,
 	size_t inval_grain_shift = 12;
 	unsigned long page_start, page_end;
 
+	/*
+	 * ATS and PASID:
+	 *
+	 * If substream_valid is clear, the PCIe TLP is sent without a PASID
+	 * prefix. In that case all ATC entries within the address range are
+	 * invalidated, including those that were requested with a PASID! There
+	 * is no way to invalidate only entries without PASID.
+	 *
+	 * When using STRTAB_STE_1_S1DSS_SSID0 (reserving CD 0 for non-PASID
+	 * traffic), translation requests without PASID create ATC entries
+	 * without PASID, which must be invalidated with substream_valid clear.
+	 * This has the unpleasant side-effect of invalidating all PASID-tagged
+	 * ATC entries within the address range.
+	 */
 	*cmd = (struct arm_smmu_cmdq_ent) {
 		.opcode			= CMDQ_OP_ATC_INV,
 		.substream_valid	= !!ssid,
@@ -1582,8 +1596,8 @@ static int arm_smmu_atc_inv_master(struct arm_smmu_master *master)
 	return arm_smmu_cmdq_issue_sync(master->smmu);
 }
 
-static int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain,
-				   int ssid, unsigned long iova, size_t size)
+int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain, int ssid,
+			    unsigned long iova, size_t size)
 {
 	int i;
 	unsigned long flags;
-- 
2.29.1


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Re: [PATCH RESEND v10 0/4] iommu: Shared Virtual Addressing for SMMUv3 (PT sharing part)

[Will Deacon]

On Fri, 6 Nov 2020 16:50:46 +0100, Jean-Philippe Brucker wrote:
> These are the remaining bits implementing iommu_sva_bind_device() for
> SMMUv3. They didn't make it into v5.10 because an Ack was missing for
> adding the PASID field to mm_struct. That is now upstream, in commit
> 52ad9bc64c74 ("mm: Add a pasid member to struct mm_struct"). No change
> since last posting [1], only rebased onto v5.10-rc2.
> 
> Note that full SVA support for SMMUv3 still needs IOPF and DVM support,
> coming soon.
> 
> [...]

Applied to arm64 (for-next/iommu/svm), thanks!

[1/4] iommu/ioasid: Add ioasid references
      https://git.kernel.org/arm64/c/cb4789b0d19f
[2/4] iommu/sva: Add PASID helpers
      https://git.kernel.org/arm64/c/cfc78dfd9b36
[3/4] iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind()
      https://git.kernel.org/arm64/c/32784a9562fb
[4/4] iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops
      https://git.kernel.org/arm64/c/2f7e8c553e98

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev
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Re: [PATCH RESEND v10 0/4] iommu: Shared Virtual Addressing for SMMUv3 (PT sharing part)

[Will Deacon]

On Fri, 6 Nov 2020 16:50:46 +0100, Jean-Philippe Brucker wrote:
> These are the remaining bits implementing iommu_sva_bind_device() for
> SMMUv3. They didn't make it into v5.10 because an Ack was missing for
> adding the PASID field to mm_struct. That is now upstream, in commit
> 52ad9bc64c74 ("mm: Add a pasid member to struct mm_struct"). No change
> since last posting [1], only rebased onto v5.10-rc2.
> 
> Note that full SVA support for SMMUv3 still needs IOPF and DVM support,
> coming soon.
> 
> [...]

Applied to arm64 (for-next/iommu/svm), thanks!

[1/4] iommu/ioasid: Add ioasid references
      https://git.kernel.org/arm64/c/cb4789b0d19f
[2/4] iommu/sva: Add PASID helpers
      https://git.kernel.org/arm64/c/cfc78dfd9b36
[3/4] iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind()
      https://git.kernel.org/arm64/c/32784a9562fb
[4/4] iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops
      https://git.kernel.org/arm64/c/2f7e8c553e98

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev

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