iommu: introduce bind_pasid_table API function

hulk inclusion
category: feature
bugzilla: 14369
CVE: NA
-------------------

Virtual IOMMU was proposed to support Shared Virtual Memory (SVM)
use in the guest:
https://lists.gnu.org/archive/html/qemu-devel/2016-11/msg05311.html

As part of the proposed architecture, when an SVM capable PCI
device is assigned to a guest, nested mode is turned on. Guest owns the
first level page tables (request with PASID) which performs GVA->GPA
translation. Second level page tables are owned by the host for GPA->HPA
translation for both request with and without PASID.

A new IOMMU driver interface is therefore needed to perform tasks as
follows:
* Enable nested translation and appropriate translation type
* Assign guest PASID table pointer (in GPA) and size to host IOMMU

This patch introduces new API functions to perform bind/unbind guest PASID
tables. Based on common data, model specific IOMMU drivers can be extended
to perform the specific steps for binding pasid table of assigned devices.
Signed-off-by: NJean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: NLiu, Yi L <yi.l.liu@linux.intel.com>
Signed-off-by: NAshok Raj <ashok.raj@intel.com>
Signed-off-by: NJacob Pan <jacob.jun.pan@linux.intel.com>
[Backported to 4.19
-add SPDX-License-Identifier]
Signed-off-by: NFang Lijun <fanglijun3@huawei.com>
Reviewed-by: NHanjun Guo <guohanjun@huawei.com>
Reviewed-by: NZhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/iommu/iommu.c

@@ -1400,6 +1400,25 @@ int iommu_attach_device(struct iommu_domain *domain, struct device *dev)
 }
 EXPORT_SYMBOL_GPL(iommu_attach_device);
 
+int iommu_bind_pasid_table(struct iommu_domain *domain, struct device *dev,
+			struct pasid_table_config *pasidt_binfo)
+{
+	if (unlikely(!domain->ops->bind_pasid_table))
+		return -ENODEV;
+
+	return domain->ops->bind_pasid_table(domain, dev, pasidt_binfo);
+}
+EXPORT_SYMBOL_GPL(iommu_bind_pasid_table);
+
+void iommu_unbind_pasid_table(struct iommu_domain *domain, struct device *dev)
+{
+	if (unlikely(!domain->ops->unbind_pasid_table))
+		return;
+
+	domain->ops->unbind_pasid_table(domain, dev);
+}
+EXPORT_SYMBOL_GPL(iommu_unbind_pasid_table);
+
 static void __iommu_detach_device(struct iommu_domain *domain,
 				  struct device *dev)
 {

include/linux/iommu.h

@@ -25,6 +25,7 @@
 #include <linux/errno.h>
 #include <linux/err.h>
 #include <linux/of.h>
+#include <uapi/linux/iommu.h>
 
 #define IOMMU_READ	(1 << 0)
 #define IOMMU_WRITE	(1 << 1)
@@ -186,6 +187,8 @@ struct iommu_resv_region {
  * @domain_get_windows: Return the number of windows for a domain
  * @of_xlate: add OF master IDs to iommu grouping
  * @pgsize_bitmap: bitmap of all possible supported page sizes
+ * @bind_pasid_table: bind pasid table pointer for guest SVM
+ * @unbind_pasid_table: unbind pasid table pointer and restore defaults
  */
 struct iommu_ops {
 	bool (*capable)(enum iommu_cap);
@@ -230,8 +233,14 @@ struct iommu_ops {
 	u32 (*domain_get_windows)(struct iommu_domain *domain);
 
 	int (*of_xlate)(struct device *dev, struct of_phandle_args *args);
+
 	bool (*is_attach_deferred)(struct iommu_domain *domain, struct device *dev);
 
+	int (*bind_pasid_table)(struct iommu_domain *domain, struct device *dev,
+				struct pasid_table_config *pasidt_binfo);
+	void (*unbind_pasid_table)(struct iommu_domain *domain,
+				struct device *dev);
+
 	unsigned long pgsize_bitmap;
 };
 
@@ -293,6 +302,10 @@ extern int iommu_attach_device(struct iommu_domain *domain,
 			       struct device *dev);
 extern void iommu_detach_device(struct iommu_domain *domain,
 				struct device *dev);
+extern int iommu_bind_pasid_table(struct iommu_domain *domain,
+		struct device *dev, struct pasid_table_config *pasidt_binfo);
+extern void iommu_unbind_pasid_table(struct iommu_domain *domain,
+				struct device *dev);
 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,
@@ -700,6 +713,19 @@ struct iommu_domain *iommu_group_unshare_domain(struct iommu_group *group)
 {
 	return NULL;
 }
+
+static inline
+int iommu_bind_pasid_table(struct iommu_domain *domain, struct device *dev,
+			struct pasid_table_config *pasidt_binfo)
+{
+	return -EINVAL;
+}
+
+static inline
+void iommu_unbind_pasid_table(struct iommu_domain *domain, struct device *dev)
+{
+}
+
 #endif /* CONFIG_IOMMU_API */
 
 #ifdef CONFIG_IOMMU_DEBUGFS

include/uapi/linux/iommu.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * IOMMU user API definitions
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _UAPI_IOMMU_H
+#define _UAPI_IOMMU_H
+
+#include <linux/types.h>
+
+/**
+ * PASID table data used to bind guest PASID table to the host IOMMU. This will
+ * enable guest managed first level page tables.
+ * @version: for future extensions and identification of the data format
+ * @bytes: size of this structure
+ * @base_ptr:	PASID table pointer
+ * @pasid_bits:	number of bits supported in the guest PASID table, must be less
+ *		or equal than the host supported PASID size.
+ */
+struct pasid_table_config {
+	__u32 version;
+#define PASID_TABLE_CFG_VERSION 1
+	__u32 bytes;
+	__u64 base_ptr;
+	__u8 pasid_bits;
+};
+
+#endif /* _UAPI_IOMMU_H */