[PATCH v10 01/13] iommu: Introduce attach/detach_pasid_table API

[Eric Auger]

From: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>

In virtualization use case, when a guest is assigned
a PCI host device, protected by a virtual IOMMU on the guest,
the physical IOMMU must be programmed to be consistent with
the guest mappings. If the physical IOMMU supports two
translation stages it makes sense to program guest mappings
onto the first stage/level (ARM/Intel terminology) while the host
owns the stage/level 2.

In that case, it is mandated to trap on guest configuration
settings and pass those to the physical iommu driver.

This patch adds a new API to the iommu subsystem that allows
to set/unset the pasid table information.

A generic iommu_pasid_table_config struct is introduced in
a new iommu.h uapi header. This is going to be used by the VFIO
user API.

Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx>
Signed-off-by: Liu, Yi L <yi.l.liu@xxxxxxxxxxxxxxx>
Signed-off-by: Ashok Raj <ashok.raj@xxxxxxxxx>
Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
Reviewed-by: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx>
---
 drivers/iommu/iommu.c      | 19 ++++++++++++++
 include/linux/iommu.h      | 18 ++++++++++++++
 include/uapi/linux/iommu.h | 51 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 88 insertions(+)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 3e3528436e0b..7cfc285bac17 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1723,6 +1723,25 @@ int iommu_sva_unbind_gpasid(struct iommu_domain *domain, struct device *dev,
 }
 EXPORT_SYMBOL_GPL(iommu_sva_unbind_gpasid);
 
+int iommu_attach_pasid_table(struct iommu_domain *domain,
+			     struct iommu_pasid_table_config *cfg)
+{
+	if (unlikely(!domain->ops->attach_pasid_table))
+		return -ENODEV;
+
+	return domain->ops->attach_pasid_table(domain, cfg);
+}
+EXPORT_SYMBOL_GPL(iommu_attach_pasid_table);
+
+void iommu_detach_pasid_table(struct iommu_domain *domain)
+{
+	if (unlikely(!domain->ops->detach_pasid_table))
+		return;
+
+	domain->ops->detach_pasid_table(domain);
+}
+EXPORT_SYMBOL_GPL(iommu_detach_pasid_table);
+
 static void __iommu_detach_device(struct iommu_domain *domain,
 				  struct device *dev)
 {
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index d1b5f4d98569..d91c7912ec3d 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -248,6 +248,8 @@ struct iommu_iotlb_gather {
  * @cache_invalidate: invalidate translation caches
  * @sva_bind_gpasid: bind guest pasid and mm
  * @sva_unbind_gpasid: unbind guest pasid and mm
+ * @attach_pasid_table: attach a pasid table
+ * @detach_pasid_table: detach the pasid table
  * @pgsize_bitmap: bitmap of all possible supported page sizes
  * @owner: Driver module providing these ops
  */
@@ -307,6 +309,9 @@ struct iommu_ops {
 				      void *drvdata);
 	void (*sva_unbind)(struct iommu_sva *handle);
 	int (*sva_get_pasid)(struct iommu_sva *handle);
+	int (*attach_pasid_table)(struct iommu_domain *domain,
+				  struct iommu_pasid_table_config *cfg);
+	void (*detach_pasid_table)(struct iommu_domain *domain);
 
 	int (*page_response)(struct device *dev,
 			     struct iommu_fault_event *evt,
@@ -443,6 +448,9 @@ extern int iommu_sva_bind_gpasid(struct iommu_domain *domain,
 		struct device *dev, struct iommu_gpasid_bind_data *data);
 extern int iommu_sva_unbind_gpasid(struct iommu_domain *domain,
 				struct device *dev, ioasid_t pasid);
+extern int iommu_attach_pasid_table(struct iommu_domain *domain,
+				    struct iommu_pasid_table_config *cfg);
+extern void iommu_detach_pasid_table(struct iommu_domain *domain);
 extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev);
 extern struct iommu_domain *iommu_get_dma_domain(struct device *dev);
 extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
@@ -1033,6 +1041,16 @@ iommu_aux_get_pasid(struct iommu_domain *domain, struct device *dev)
 	return -ENODEV;
 }
 
+static inline
+int iommu_attach_pasid_table(struct iommu_domain *domain,
+			     struct iommu_pasid_table_config *cfg)
+{
+	return -ENODEV;
+}
+
+static inline
+void iommu_detach_pasid_table(struct iommu_domain *domain) {}
+
 static inline struct iommu_sva *
 iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
 {
diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
index 4ad3496e5c43..8d00be10dc6d 100644
--- a/include/uapi/linux/iommu.h
+++ b/include/uapi/linux/iommu.h
@@ -321,4 +321,55 @@ struct iommu_gpasid_bind_data {
 	};
 };
 
+/**
+ * struct iommu_pasid_smmuv3 - ARM SMMUv3 Stream Table Entry stage 1 related
+ *     information
+ * @version: API version of this structure
+ * @s1fmt: STE s1fmt (format of the CD table: single CD, linear table
+ *         or 2-level table)
+ * @s1dss: STE s1dss (specifies the behavior when @pasid_bits != 0
+ *         and no PASID is passed along with the incoming transaction)
+ * @padding: reserved for future use (should be zero)
+ *
+ * The PASID table is referred to as the Context Descriptor (CD) table on ARM
+ * SMMUv3. Please refer to the ARM SMMU 3.x spec (ARM IHI 0070A) for full
+ * details.
+ */
+struct iommu_pasid_smmuv3 {
+#define PASID_TABLE_SMMUV3_CFG_VERSION_1 1
+	__u32	version;
+	__u8	s1fmt;
+	__u8	s1dss;
+	__u8	padding[2];
+};
+
+/**
+ * struct iommu_pasid_table_config - PASID table data used to bind guest PASID
+ *     table to the host IOMMU
+ * @version: API version to prepare for future extensions
+ * @format: format of the PASID table
+ * @base_ptr: guest physical address of the PASID table
+ * @pasid_bits: number of PASID bits used in the PASID table
+ * @config: indicates whether the guest translation stage must
+ *          be translated, bypassed or aborted.
+ * @padding: reserved for future use (should be zero)
+ * @smmuv3: table information when @format is %IOMMU_PASID_FORMAT_SMMUV3
+ */
+struct iommu_pasid_table_config {
+#define PASID_TABLE_CFG_VERSION_1 1
+	__u32	version;
+#define IOMMU_PASID_FORMAT_SMMUV3	1
+	__u32	format;
+	__u64	base_ptr;
+	__u8	pasid_bits;
+#define IOMMU_PASID_CONFIG_TRANSLATE	1
+#define IOMMU_PASID_CONFIG_BYPASS	2
+#define IOMMU_PASID_CONFIG_ABORT	3
+	__u8	config;
+	__u8    padding[6];
+	union {
+		struct iommu_pasid_smmuv3 smmuv3;
+	};
+};
+
 #endif /* _UAPI_IOMMU_H */
-- 
2.20.1