iommu/vt-d: Remove struct intel_svm

The struct intel_svm was used for keeping attached devices info for sva
domain. Since sva domain is a kind of iommu_domain, the struct
dmar_domain should centralize all info of a sva domain, including the
info of attached devices. Therefore, retire struct intel_svm and clean up
the code.

Besides, register mmu notifier callback  in domain_alloc_sva() callback
which allows the memory management notifier lifetime to follow the lifetime
of the iommu_domain. Call mmu_notifier_put() in the domain free and defer
the real free to the mmu free_notifier callback.

Co-developed-by: Tina Zhang <[email protected]>
Signed-off-by: Tina Zhang <[email protected]>
Signed-off-by: Lu Baolu <[email protected]>
Reviewed-by: Kevin Tian <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>

Author: LuBaolu

drivers/iommu/intel/iommu.c

@@ -3683,8 +3683,6 @@ static struct iommu_domain *intel_iommu_domain_alloc(unsigned type)
 		return domain;
 	case IOMMU_DOMAIN_IDENTITY:
 		return &si_domain->domain;
-	case IOMMU_DOMAIN_SVA:
-		return intel_svm_domain_alloc();
 	default:
 		return NULL;
 	}
@@ -4382,14 +4380,6 @@ static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
 		goto out_tear_down;
 	dmar_domain = to_dmar_domain(domain);
 
-	/*
-	 * The SVA implementation needs to handle its own stuffs like the mm
-	 * notification. Before consolidating that code into iommu core, let
-	 * the intel sva code handle it.
-	 */
-	if (domain->type == IOMMU_DOMAIN_SVA)
-		intel_svm_remove_dev_pasid(domain);
-
 	spin_lock_irqsave(&dmar_domain->lock, flags);
 	list_for_each_entry(curr, &dmar_domain->dev_pasids, link_domain) {
 		if (curr->dev == dev && curr->pasid == pasid) {
@@ -4624,6 +4614,7 @@ const struct iommu_ops intel_iommu_ops = {
 	.hw_info		= intel_iommu_hw_info,
 	.domain_alloc		= intel_iommu_domain_alloc,
 	.domain_alloc_user	= intel_iommu_domain_alloc_user,
+	.domain_alloc_sva	= intel_svm_domain_alloc,
 	.probe_device		= intel_iommu_probe_device,
 	.probe_finalize		= intel_iommu_probe_finalize,
 	.release_device		= intel_iommu_release_device,

drivers/iommu/intel/iommu.h

@@ -648,8 +648,12 @@ struct dmar_domain {
 			/* link to parent domain siblings */
 			struct list_head s2_link;
 		};
+
+		/* SVA domain */
+		struct {
+			struct mmu_notifier notifier;
+		};
 	};
-	struct intel_svm *svm;
 
 	struct iommu_domain domain;	/* generic domain data structure for
 					   iommu core */
@@ -1149,26 +1153,16 @@ int intel_svm_enable_prq(struct intel_iommu *iommu);
 int intel_svm_finish_prq(struct intel_iommu *iommu);
 void intel_svm_page_response(struct device *dev, struct iopf_fault *evt,
 			     struct iommu_page_response *msg);
-struct iommu_domain *intel_svm_domain_alloc(void);
-void intel_svm_remove_dev_pasid(struct iommu_domain *domain);
+struct iommu_domain *intel_svm_domain_alloc(struct device *dev,
+					    struct mm_struct *mm);
 void intel_drain_pasid_prq(struct device *dev, u32 pasid);
-
-struct intel_svm {
-	struct mmu_notifier notifier;
-	struct mm_struct *mm;
-	u32 pasid;
-	struct dmar_domain *domain;
-};
 #else
 static inline void intel_svm_check(struct intel_iommu *iommu) {}
 static inline void intel_drain_pasid_prq(struct device *dev, u32 pasid) {}
-static inline struct iommu_domain *intel_svm_domain_alloc(void)
-{
-	return NULL;
-}
-
-static inline void intel_svm_remove_dev_pasid(struct iommu_domain *domain)
+static inline struct iommu_domain *intel_svm_domain_alloc(struct device *dev,
+							  struct mm_struct *mm)
 {
+	return ERR_PTR(-ENODEV);
 }
 #endif
 

drivers/iommu/intel/svm.c

@@ -26,23 +26,6 @@
 
 static irqreturn_t prq_event_thread(int irq, void *d);
 
-static DEFINE_XARRAY_ALLOC(pasid_private_array);
-static int pasid_private_add(ioasid_t pasid, void *priv)
-{
-	return xa_alloc(&pasid_private_array, &pasid, priv,
-			XA_LIMIT(pasid, pasid), GFP_ATOMIC);
-}
-
-static void pasid_private_remove(ioasid_t pasid)
-{
-	xa_erase(&pasid_private_array, pasid);
-}
-
-static void *pasid_private_find(ioasid_t pasid)
-{
-	return xa_load(&pasid_private_array, pasid);
-}
-
 int intel_svm_enable_prq(struct intel_iommu *iommu)
 {
 	struct iopf_queue *iopfq;
@@ -156,10 +139,9 @@ static void intel_arch_invalidate_secondary_tlbs(struct mmu_notifier *mn,
 					struct mm_struct *mm,
 					unsigned long start, unsigned long end)
 {
-	struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
-	struct dmar_domain *domain = svm->domain;
+	struct dmar_domain *domain = container_of(mn, struct dmar_domain, notifier);
 
-	if (start == 0 && end == -1UL) {
+	if (start == 0 && end == ULONG_MAX) {
 		cache_tag_flush_all(domain);
 		return;
 	}
@@ -174,8 +156,7 @@ static void intel_arch_invalidate_secondary_tlbs(struct mmu_notifier *mn,
 
 static void intel_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
 {
-	struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
-	struct dmar_domain *domain = svm->domain;
+	struct dmar_domain *domain = container_of(mn, struct dmar_domain, notifier);
 	struct dev_pasid_info *dev_pasid;
 	struct device_domain_info *info;
 	unsigned long flags;
@@ -202,9 +183,15 @@ static void intel_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
 
 }
 
+static void intel_mm_free_notifier(struct mmu_notifier *mn)
+{
+	kfree(container_of(mn, struct dmar_domain, notifier));
+}
+
 static const struct mmu_notifier_ops intel_mmuops = {
 	.release = intel_mm_release,
 	.arch_invalidate_secondary_tlbs = intel_arch_invalidate_secondary_tlbs,
+	.free_notifier = intel_mm_free_notifier,
 };
 
 static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
@@ -215,40 +202,13 @@ static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
 	struct intel_iommu *iommu = info->iommu;
 	struct mm_struct *mm = domain->mm;
 	struct dev_pasid_info *dev_pasid;
-	struct intel_svm *svm;
 	unsigned long sflags;
 	unsigned long flags;
 	int ret = 0;
 
-	svm = pasid_private_find(pasid);
-	if (!svm) {
-		svm = kzalloc(sizeof(*svm), GFP_KERNEL);
-		if (!svm)
-			return -ENOMEM;
-
-		svm->pasid = pasid;
-		svm->mm = mm;
-
-		svm->notifier.ops = &intel_mmuops;
-		svm->domain = to_dmar_domain(domain);
-		ret = mmu_notifier_register(&svm->notifier, mm);
-		if (ret) {
-			kfree(svm);
-			return ret;
-		}
-
-		ret = pasid_private_add(svm->pasid, svm);
-		if (ret) {
-			mmu_notifier_unregister(&svm->notifier, mm);
-			kfree(svm);
-			return ret;
-		}
-	}
-
-	dmar_domain->svm = svm;
 	dev_pasid = kzalloc(sizeof(*dev_pasid), GFP_KERNEL);
 	if (!dev_pasid)
-		goto free_svm;
+		return -ENOMEM;
 
 	dev_pasid->dev = dev;
 	dev_pasid->pasid = pasid;
@@ -274,30 +234,10 @@ static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
 	cache_tag_unassign_domain(to_dmar_domain(domain), dev, pasid);
 free_dev_pasid:
 	kfree(dev_pasid);
-free_svm:
-	if (list_empty(&dmar_domain->dev_pasids)) {
-		mmu_notifier_unregister(&svm->notifier, mm);
-		pasid_private_remove(pasid);
-		kfree(svm);
-	}
 
 	return ret;
 }
 
-void intel_svm_remove_dev_pasid(struct iommu_domain *domain)
-{
-	struct dmar_domain *dmar_domain = to_dmar_domain(domain);
-	struct intel_svm *svm = dmar_domain->svm;
-	struct mm_struct *mm = domain->mm;
-
-	if (list_empty(&dmar_domain->dev_pasids)) {
-		if (svm->notifier.ops)
-			mmu_notifier_unregister(&svm->notifier, mm);
-		pasid_private_remove(svm->pasid);
-		kfree(svm);
-	}
-}
-
 /* Page request queue descriptor */
 struct page_req_dsc {
 	union {
@@ -611,27 +551,40 @@ void intel_svm_page_response(struct device *dev, struct iopf_fault *evt,
 
 static void intel_svm_domain_free(struct iommu_domain *domain)
 {
-	kfree(to_dmar_domain(domain));
+	struct dmar_domain *dmar_domain = to_dmar_domain(domain);
+
+	/* dmar_domain free is deferred to the mmu free_notifier callback. */
+	mmu_notifier_put(&dmar_domain->notifier);
 }
 
 static const struct iommu_domain_ops intel_svm_domain_ops = {
 	.set_dev_pasid		= intel_svm_set_dev_pasid,
 	.free			= intel_svm_domain_free
 };
 
-struct iommu_domain *intel_svm_domain_alloc(void)
+struct iommu_domain *intel_svm_domain_alloc(struct device *dev,
+					    struct mm_struct *mm)
 {
 	struct dmar_domain *domain;
+	int ret;
 
 	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
 	if (!domain)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
+
 	domain->domain.ops = &intel_svm_domain_ops;
 	domain->use_first_level = true;
 	INIT_LIST_HEAD(&domain->dev_pasids);
 	INIT_LIST_HEAD(&domain->cache_tags);
 	spin_lock_init(&domain->cache_lock);
 	spin_lock_init(&domain->lock);
 
+	domain->notifier.ops = &intel_mmuops;
+	ret = mmu_notifier_register(&domain->notifier, mm);
+	if (ret) {
+		kfree(domain);
+		return ERR_PTR(ret);
+	}
+
 	return &domain->domain;
 }