[PATCH v3 01/16] iommu: introduce bind_pasid_table API function

Jacob Pan
2017-11-17T18:56:16Z

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: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Liu, Yi L <yi.l.liu@linux.intel.com>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
---
drivers/iommu/iommu.c | 19 +++++++++++++++++++
include/linux/iommu.h | 24 ++++++++++++++++++++++++
include/uapi/linux/iommu.h | 39 +++++++++++++++++++++++++++++++++++++++
3 files changed, 82 insertions(+)
create mode 100644 include/uapi/linux/iommu.h

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 3de5c0b..c7e0d64 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1322,6 +1322,25 @@ 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)
{
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 41b8c57..0f6f6c5 100644
--- a/include/linux/iommu.h
+++ b/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)
@@ -187,6 +188,8 @@ 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);
@@ -233,8 +236,14 @@ 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;
};

@@ -296,6 +305,10 @@ 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 int iommu_map(struct iommu_domain *domain, unsigned long iova,
phys_addr_t paddr, size_t size, int prot);
@@ -696,6 +709,17 @@ const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode)
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 */

#endif /* __LINUX_IOMMU_H */
diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
new file mode 100644
index 0000000..651ad5d
--- /dev/null
+++ b/include/uapi/linux/iommu.h
@@ -0,0 +1,39 @@
+/*
+ * 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;
+ /* reserved for extension of vendor specific config */
+ union {
+ struct {
+ /* ARM specific fields */
+ bool pasid0_dma_no_pasid;
+ } arm;
+ };
+};
+
+#endif /* _UAPI_IOMMU_H */
--
2.7.4