iommufd: Add a selftest

Cover the essential functionality of the iommufd with a simple test.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>

drivers/iommu/iommufd/Kconfig

@@ -10,3 +10,11 @@ config IOMMUFD
 	  to userspace drivers.
 
 	  If you don't know what to do here, say N.
+
+config IOMMUFD_TEST
+	bool "IOMMU Userspace API Test support"
+	depends on IOMMUFD
+	default n
+	help
+	  This is dangerous, do not enable unless running
+	  tools/testing/selftests/iommu

drivers/iommu/iommufd/Makefile

@@ -8,4 +8,6 @@ iommufd-y := \
 	pages.o \
 	vfio_compat.o
 
+iommufd-$(CONFIG_IOMMUFD_TEST) += selftest.o
+
 obj-$(CONFIG_IOMMUFD) += iommufd.o

drivers/iommu/iommufd/iommufd_private.h

@@ -98,6 +98,9 @@ enum iommufd_object_type {
 	IOMMUFD_OBJ_NONE,
 	IOMMUFD_OBJ_ANY = IOMMUFD_OBJ_NONE,
 	IOMMUFD_OBJ_DEVICE,
+#ifdef CONFIG_IOMMUFD_TEST
+	IOMMUFD_OBJ_SELFTEST,
+#endif
 	IOMMUFD_OBJ_HW_PAGETABLE,
 	IOMMUFD_OBJ_IOAS_PAGETABLE,
 	IOMMUFD_OBJ_MAX,
@@ -207,4 +210,10 @@ void iommufd_hw_pagetable_destroy(struct iommufd_object *obj);
 
 void iommufd_device_destroy(struct iommufd_object *obj);
 
+#ifdef CONFIG_IOMMUFD_TEST
+int iommufd_test(struct iommufd_ucmd *ucmd);
+void iommufd_selftest_destroy(struct iommufd_object *obj);
+extern size_t iommufd_test_memory_limit;
+#endif
+
 #endif

drivers/iommu/iommufd/iommufd_test.h

@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021, NVIDIA CORPORATION & AFFILIATES.
+ */
+#ifndef _UAPI_IOMMUFD_TEST_H
+#define _UAPI_IOMMUFD_TEST_H
+
+#include <linux/types.h>
+#include <linux/iommufd.h>
+
+enum {
+	IOMMU_TEST_OP_ADD_RESERVED,
+	IOMMU_TEST_OP_MOCK_DOMAIN,
+	IOMMU_TEST_OP_MD_CHECK_MAP,
+	IOMMU_TEST_OP_MD_CHECK_REFS,
+	IOMMU_TEST_OP_ACCESS_PAGES,
+	IOMMU_TEST_OP_SET_TEMP_MEMORY_LIMIT,
+};
+
+enum {
+	MOCK_APERTURE_START = 1UL << 24,
+	MOCK_APERTURE_LAST = (1UL << 31) - 1,
+};
+
+enum {
+	MOCK_FLAGS_ACCESS_WRITE = 1 << 0,
+};
+
+struct iommu_test_cmd {
+	__u32 size;
+	__u32 op;
+	__u32 id;
+	union {
+		struct {
+			__u32 device_id;
+		} mock_domain;
+		struct {
+			__aligned_u64 start;
+			__aligned_u64 length;
+		} add_reserved;
+		struct {
+			__aligned_u64 iova;
+			__aligned_u64 length;
+			__aligned_u64 uptr;
+		} check_map;
+		struct {
+			__aligned_u64 length;
+			__aligned_u64 uptr;
+			__u32 refs;
+		} check_refs;
+		struct {
+			__u32 flags;
+			__u32 out_access_id;
+			__aligned_u64 iova;
+			__aligned_u64 length;
+			__aligned_u64 uptr;
+		} access_pages;
+		struct {
+			__u32 limit;
+		} memory_limit;
+	};
+	__u32 last;
+};
+#define IOMMU_TEST_CMD _IO(IOMMUFD_TYPE, IOMMUFD_CMD_BASE + 32)
+
+#endif

drivers/iommu/iommufd/main.c

@@ -24,6 +24,7 @@
 #include <uapi/linux/iommufd.h>
 
 #include "iommufd_private.h"
+#include "iommufd_test.h"
 
 struct iommufd_object_ops {
 	void (*destroy)(struct iommufd_object *obj);
@@ -187,6 +188,9 @@ union ucmd_buffer {
 	struct iommu_ioas_pagetable_map map;
 	struct iommu_ioas_pagetable_unmap unmap;
 	struct iommu_destroy destroy;
+#ifdef CONFIG_IOMMUFD_TEST
+	struct iommu_test_cmd test;
+#endif
 };
 
 struct iommufd_ioctl_op {
@@ -220,6 +224,9 @@ static struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
 		 struct iommu_ioas_pagetable_unmap, length),
 	IOCTL_OP(IOMMU_VFIO_IOAS, iommufd_vfio_ioas, struct iommu_vfio_ioas,
 		 reserved),
+#ifdef CONFIG_IOMMUFD_TEST
+	IOCTL_OP(IOMMU_TEST_CMD, iommufd_test, struct iommu_test_cmd, last),
+#endif
 };
 
 static long iommufd_fops_ioctl(struct file *filp, unsigned int cmd,
@@ -296,6 +303,11 @@ static struct iommufd_object_ops iommufd_object_ops[] = {
 	[IOMMUFD_OBJ_HW_PAGETABLE] = {
 		.destroy = iommufd_hw_pagetable_destroy,
 	},
+#ifdef CONFIG_IOMMUFD_TEST
+	[IOMMUFD_OBJ_SELFTEST] = {
+		.destroy = iommufd_selftest_destroy,
+	},
+#endif
 };
 
 static struct miscdevice iommu_misc_dev = {

drivers/iommu/iommufd/pages.c

@@ -48,7 +48,11 @@
 
 #include "io_pagetable.h"
 
+#ifndef CONFIG_IOMMUFD_TEST
 #define TEMP_MEMORY_LIMIT 65536
+#else
+#define TEMP_MEMORY_LIMIT iommufd_test_memory_limit
+#endif
 #define BATCH_BACKUP_SIZE 32
 
 /*