iommu: Introduce new 'struct iommu_device'

This struct represents one hardware iommu in the iommu core
code. For now it only has the iommu-ops associated with it,
but that will be extended soon.

The register/unregister interface is also added, as well as
making use of it in the Intel and AMD IOMMU drivers.

Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: joergroedel

drivers/iommu/amd_iommu.c

@@ -112,7 +112,7 @@ static struct timer_list queue_timer;
  * Domain for untranslated devices - only allocated
  * if iommu=pt passed on kernel cmd line.
  */
-static const struct iommu_ops amd_iommu_ops;
+const struct iommu_ops amd_iommu_ops;
 
 static ATOMIC_NOTIFIER_HEAD(ppr_notifier);
 int amd_iommu_max_glx_val = -1;
@@ -3217,7 +3217,7 @@ static void amd_iommu_apply_dm_region(struct device *dev,
 	WARN_ON_ONCE(reserve_iova(&dma_dom->iovad, start, end) == NULL);
 }
 
-static const struct iommu_ops amd_iommu_ops = {
+const struct iommu_ops amd_iommu_ops = {
 	.capable = amd_iommu_capable,
 	.domain_alloc = amd_iommu_domain_alloc,
 	.domain_free  = amd_iommu_domain_free,

drivers/iommu/amd_iommu_init.c

@@ -94,6 +94,8 @@
  * out of it.
  */
 
+extern const struct iommu_ops amd_iommu_ops;
+
 /*
  * structure describing one IOMMU in the ACPI table. Typically followed by one
  * or more ivhd_entrys.
@@ -1639,6 +1641,9 @@ static int iommu_init_pci(struct amd_iommu *iommu)
 					       amd_iommu_groups, "ivhd%d",
 					       iommu->index);
 
+	iommu_device_set_ops(&iommu->iommu, &amd_iommu_ops);
+	iommu_device_register(&iommu->iommu);
+
 	return pci_enable_device(iommu->dev);
 }
 

drivers/iommu/amd_iommu_types.h

@@ -538,6 +538,9 @@ struct amd_iommu {
 	/* IOMMU sysfs device */
 	struct device *iommu_dev;
 
+	/* Handle for IOMMU core code */
+	struct iommu_device iommu;
+
 	/*
 	 * We can't rely on the BIOS to restore all values on reinit, so we
 	 * need to stash them

drivers/iommu/dmar.c

@@ -74,6 +74,8 @@ static unsigned long dmar_seq_ids[BITS_TO_LONGS(DMAR_UNITS_SUPPORTED)];
 static int alloc_iommu(struct dmar_drhd_unit *drhd);
 static void free_iommu(struct intel_iommu *iommu);
 
+extern const struct iommu_ops intel_iommu_ops;
+
 static void dmar_register_drhd_unit(struct dmar_drhd_unit *drhd)
 {
 	/*
@@ -1084,6 +1086,12 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)
 			err = PTR_ERR(iommu->iommu_dev);
 			goto err_unmap;
 		}
+
+		iommu_device_set_ops(&iommu->iommu, &intel_iommu_ops);
+
+		err = iommu_device_register(&iommu->iommu);
+		if (err)
+			goto err_unmap;
 	}
 
 	drhd->iommu = iommu;
@@ -1102,6 +1110,7 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)
 static void free_iommu(struct intel_iommu *iommu)
 {
 	iommu_device_destroy(iommu->iommu_dev);
+	iommu_device_unregister(&iommu->iommu);
 
 	if (iommu->irq) {
 		if (iommu->pr_irq) {

drivers/iommu/intel-iommu.c

@@ -547,7 +547,7 @@ EXPORT_SYMBOL_GPL(intel_iommu_gfx_mapped);
 static DEFINE_SPINLOCK(device_domain_lock);
 static LIST_HEAD(device_domain_list);
 
-static const struct iommu_ops intel_iommu_ops;
+const struct iommu_ops intel_iommu_ops;
 
 static bool translation_pre_enabled(struct intel_iommu *iommu)
 {
@@ -5292,7 +5292,7 @@ struct intel_iommu *intel_svm_device_to_iommu(struct device *dev)
 }
 #endif /* CONFIG_INTEL_IOMMU_SVM */
 
-static const struct iommu_ops intel_iommu_ops = {
+const struct iommu_ops intel_iommu_ops = {
 	.capable	= intel_iommu_capable,
 	.domain_alloc	= intel_iommu_domain_alloc,
 	.domain_free	= intel_iommu_domain_free,

drivers/iommu/iommu.c

@@ -77,6 +77,25 @@ struct iommu_group_attribute iommu_group_attr_##_name =		\
 #define to_iommu_group(_kobj)		\
 	container_of(_kobj, struct iommu_group, kobj)
 
+static LIST_HEAD(iommu_device_list);
+static DEFINE_SPINLOCK(iommu_device_lock);
+
+int iommu_device_register(struct iommu_device *iommu)
+{
+	spin_lock(&iommu_device_lock);
+	list_add_tail(&iommu->list, &iommu_device_list);
+	spin_unlock(&iommu_device_lock);
+
+	return 0;
+}
+
+void iommu_device_unregister(struct iommu_device *iommu)
+{
+	spin_lock(&iommu_device_lock);
+	list_del(&iommu->list);
+	spin_unlock(&iommu_device_lock);
+}
+
 static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
 						 unsigned type);
 static int __iommu_attach_device(struct iommu_domain *domain,

include/linux/intel-iommu.h

@@ -29,6 +29,7 @@
 #include <linux/dma_remapping.h>
 #include <linux/mmu_notifier.h>
 #include <linux/list.h>
+#include <linux/iommu.h>
 #include <asm/cacheflush.h>
 #include <asm/iommu.h>
 
@@ -440,6 +441,7 @@ struct intel_iommu {
 	struct irq_domain *ir_msi_domain;
 #endif
 	struct device	*iommu_dev; /* IOMMU-sysfs device */
+	struct iommu_device iommu;  /* IOMMU core code handle */
 	int		node;
 	u32		flags;      /* Software defined flags */
 };

include/linux/iommu.h

@@ -204,6 +204,26 @@ struct iommu_ops {
 	unsigned long pgsize_bitmap;
 };
 
+/**
+ * struct iommu_device - IOMMU core representation of one IOMMU hardware
+ *			 instance
+ * @list: Used by the iommu-core to keep a list of registered iommus
+ * @ops: iommu-ops for talking to this iommu
+ */
+struct iommu_device {
+	struct list_head list;
+	const struct iommu_ops *ops;
+};
+
+int  iommu_device_register(struct iommu_device *iommu);
+void iommu_device_unregister(struct iommu_device *iommu);
+
+static inline void iommu_device_set_ops(struct iommu_device *iommu,
+					const struct iommu_ops *ops)
+{
+	iommu->ops = ops;
+}
+
 #define IOMMU_GROUP_NOTIFY_ADD_DEVICE		1 /* Device added */
 #define IOMMU_GROUP_NOTIFY_DEL_DEVICE		2 /* Pre Device removed */
 #define IOMMU_GROUP_NOTIFY_BIND_DRIVER		3 /* Pre Driver bind */
@@ -361,6 +381,7 @@ const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode);
 struct iommu_ops {};
 struct iommu_group {};
 struct iommu_fwspec {};
+struct iommu_device {};
 
 static inline bool iommu_present(struct bus_type *bus)
 {
@@ -558,6 +579,20 @@ static inline void iommu_device_destroy(struct device *dev)
 {
 }
 
+static inline int  iommu_device_register(struct iommu_device *iommu)
+{
+	return -ENODEV;
+}
+
+static inline void iommu_device_set_ops(struct iommu_device *iommu,
+					const struct iommu_ops *ops)
+{
+}
+
+static inline void iommu_device_unregister(struct iommu_device *iommu)
+{
+}
+
 static inline int iommu_device_link(struct device *dev, struct device *link)
 {
 	return -EINVAL;