iommufd: Add a selftest

Cover the essential functionality of the iommufd with a directed test from
userspace. This aims to achieve reasonable functional coverage using the
in-kernel self test framework.

A second test does a failure injection sweep of the success paths to study
error unwind behaviors.

This allows achieving high coverage of the corner cases in pages.c.

The selftest requires CONFIG_IOMMUFD_TEST to be enabled, and several huge
pages which may require:

  echo 4 > /proc/sys/vm/nr_hugepages

Link: https://lore.kernel.org/r/19-v6-a196d26f289e+11787-iommufd_jgg@nvidia.comTested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com> # s390
Tested-by: Yi Liu <yi.l.liu@intel.com>
Tested-by: Eric Auger <eric.auger@redhat.com> # aarch64
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

tools/testing/selftests/Makefile

@@ -27,6 +27,7 @@ TARGETS += ftrace
 TARGETS += futex
 TARGETS += gpio
 TARGETS += intel_pstate
+TARGETS += iommu
 TARGETS += ipc
 TARGETS += ir
 TARGETS += kcmp

tools/testing/selftests/iommu/.gitignore

+# SPDX-License-Identifier: GPL-2.0-only
+/iommufd
+/iommufd_fail_nth

tools/testing/selftests/iommu/Makefile

+# SPDX-License-Identifier: GPL-2.0-only
+CFLAGS += -Wall -O2 -Wno-unused-function
+CFLAGS += -I../../../../include/uapi/
+CFLAGS += -I../../../../include/
+
+CFLAGS += -D_GNU_SOURCE
+
+TEST_GEN_PROGS :=
+TEST_GEN_PROGS += iommufd
+TEST_GEN_PROGS += iommufd_fail_nth
+
+include ../lib.mk

tools/testing/selftests/iommu/config

+CONFIG_IOMMUFD
+CONFIG_IOMMUFD_TEST

tools/testing/selftests/iommu/iommufd_utils.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (c) 2021-2022, NVIDIA CORPORATION & AFFILIATES */
+#ifndef __SELFTEST_IOMMUFD_UTILS
+#define __SELFTEST_IOMMUFD_UTILS
+
+#include <unistd.h>
+#include <stddef.h>
+#include <sys/fcntl.h>
+#include <sys/ioctl.h>
+#include <stdint.h>
+#include <assert.h>
+
+#include "../kselftest_harness.h"
+#include "../../../../drivers/iommu/iommufd/iommufd_test.h"
+
+/* Hack to make assertions more readable */
+#define _IOMMU_TEST_CMD(x) IOMMU_TEST_CMD
+
+static void *buffer;
+static unsigned long BUFFER_SIZE;
+
+/*
+ * Have the kernel check the refcount on pages. I don't know why a freshly
+ * mmap'd anon non-compound page starts out with a ref of 3
+ */
+#define check_refs(_ptr, _length, _refs)                                      \
+	({                                                                    \
+		struct iommu_test_cmd test_cmd = {                            \
+			.size = sizeof(test_cmd),                             \
+			.op = IOMMU_TEST_OP_MD_CHECK_REFS,                    \
+			.check_refs = { .length = _length,                    \
+					.uptr = (uintptr_t)(_ptr),            \
+					.refs = _refs },                      \
+		};                                                            \
+		ASSERT_EQ(0,                                                  \
+			  ioctl(self->fd,                                     \
+				_IOMMU_TEST_CMD(IOMMU_TEST_OP_MD_CHECK_REFS), \
+				&test_cmd));                                  \
+	})
+
+static int _test_cmd_mock_domain(int fd, unsigned int ioas_id, __u32 *device_id,
+				 __u32 *hwpt_id)
+{
+	struct iommu_test_cmd cmd = {
+		.size = sizeof(cmd),
+		.op = IOMMU_TEST_OP_MOCK_DOMAIN,
+		.id = ioas_id,
+		.mock_domain = {},
+	};
+	int ret;
+
+	ret = ioctl(fd, IOMMU_TEST_CMD, &cmd);
+	if (ret)
+		return ret;
+	if (device_id)
+		*device_id = cmd.mock_domain.out_device_id;
+	assert(cmd.id != 0);
+	if (hwpt_id)
+		*hwpt_id = cmd.mock_domain.out_hwpt_id;
+	return 0;
+}
+#define test_cmd_mock_domain(ioas_id, device_id, hwpt_id)                \
+	ASSERT_EQ(0, _test_cmd_mock_domain(self->fd, ioas_id, device_id, \
+					   hwpt_id))
+#define test_err_mock_domain(_errno, ioas_id, device_id, hwpt_id)     \
+	EXPECT_ERRNO(_errno, _test_cmd_mock_domain(self->fd, ioas_id, \
+						   device_id, hwpt_id))
+
+static int _test_cmd_create_access(int fd, unsigned int ioas_id,
+				   __u32 *access_id, unsigned int flags)
+{
+	struct iommu_test_cmd cmd = {
+		.size = sizeof(cmd),
+		.op = IOMMU_TEST_OP_CREATE_ACCESS,
+		.id = ioas_id,
+		.create_access = { .flags = flags },
+	};
+	int ret;
+
+	ret = ioctl(fd, IOMMU_TEST_CMD, &cmd);
+	if (ret)
+		return ret;
+	*access_id = cmd.create_access.out_access_fd;
+	return 0;
+}
+#define test_cmd_create_access(ioas_id, access_id, flags)                  \
+	ASSERT_EQ(0, _test_cmd_create_access(self->fd, ioas_id, access_id, \
+					     flags))
+
+static int _test_cmd_destroy_access(unsigned int access_id)
+{
+	return close(access_id);
+}
+#define test_cmd_destroy_access(access_id) \
+	ASSERT_EQ(0, _test_cmd_destroy_access(access_id))
+
+static int _test_cmd_destroy_access_pages(int fd, unsigned int access_id,
+					  unsigned int access_pages_id)
+{
+	struct iommu_test_cmd cmd = {
+		.size = sizeof(cmd),
+		.op = IOMMU_TEST_OP_DESTROY_ACCESS_PAGES,
+		.id = access_id,
+		.destroy_access_pages = { .access_pages_id = access_pages_id },
+	};
+	return ioctl(fd, IOMMU_TEST_CMD, &cmd);
+}
+#define test_cmd_destroy_access_pages(access_id, access_pages_id)        \
+	ASSERT_EQ(0, _test_cmd_destroy_access_pages(self->fd, access_id, \
+						    access_pages_id))
+#define test_err_destroy_access_pages(_errno, access_id, access_pages_id) \
+	EXPECT_ERRNO(_errno, _test_cmd_destroy_access_pages(              \
+				     self->fd, access_id, access_pages_id))
+
+static int _test_ioctl_destroy(int fd, unsigned int id)
+{
+	struct iommu_destroy cmd = {
+		.size = sizeof(cmd),
+		.id = id,
+	};
+	return ioctl(fd, IOMMU_DESTROY, &cmd);
+}
+#define test_ioctl_destroy(id) ASSERT_EQ(0, _test_ioctl_destroy(self->fd, id))
+
+static int _test_ioctl_ioas_alloc(int fd, __u32 *id)
+{
+	struct iommu_ioas_alloc cmd = {
+		.size = sizeof(cmd),
+	};
+	int ret;
+
+	ret = ioctl(fd, IOMMU_IOAS_ALLOC, &cmd);
+	if (ret)
+		return ret;
+	*id = cmd.out_ioas_id;
+	return 0;
+}
+#define test_ioctl_ioas_alloc(id)                                   \
+	({                                                          \
+		ASSERT_EQ(0, _test_ioctl_ioas_alloc(self->fd, id)); \
+		ASSERT_NE(0, *(id));                                \
+	})
+
+static int _test_ioctl_ioas_map(int fd, unsigned int ioas_id, void *buffer,
+				size_t length, __u64 *iova, unsigned int flags)
+{
+	struct iommu_ioas_map cmd = {
+		.size = sizeof(cmd),
+		.flags = flags,
+		.ioas_id = ioas_id,
+		.user_va = (uintptr_t)buffer,
+		.length = length,
+	};
+	int ret;
+
+	if (flags & IOMMU_IOAS_MAP_FIXED_IOVA)
+		cmd.iova = *iova;
+
+	ret = ioctl(fd, IOMMU_IOAS_MAP, &cmd);
+	*iova = cmd.iova;
+	return ret;
+}
+#define test_ioctl_ioas_map(buffer, length, iova_p)                        \
+	ASSERT_EQ(0, _test_ioctl_ioas_map(self->fd, self->ioas_id, buffer, \
+					  length, iova_p,                  \
+					  IOMMU_IOAS_MAP_WRITEABLE |       \
+						  IOMMU_IOAS_MAP_READABLE))
+
+#define test_err_ioctl_ioas_map(_errno, buffer, length, iova_p)            \
+	EXPECT_ERRNO(_errno,                                               \
+		     _test_ioctl_ioas_map(self->fd, self->ioas_id, buffer, \
+					  length, iova_p,                  \
+					  IOMMU_IOAS_MAP_WRITEABLE |       \
+						  IOMMU_IOAS_MAP_READABLE))
+
+#define test_ioctl_ioas_map_id(ioas_id, buffer, length, iova_p)              \
+	ASSERT_EQ(0, _test_ioctl_ioas_map(self->fd, ioas_id, buffer, length, \
+					  iova_p,                            \
+					  IOMMU_IOAS_MAP_WRITEABLE |         \
+						  IOMMU_IOAS_MAP_READABLE))
+
+#define test_ioctl_ioas_map_fixed(buffer, length, iova)                       \
+	({                                                                    \
+		__u64 __iova = iova;                                          \
+		ASSERT_EQ(0, _test_ioctl_ioas_map(                            \
+				     self->fd, self->ioas_id, buffer, length, \
+				     &__iova,                                 \
+				     IOMMU_IOAS_MAP_FIXED_IOVA |              \
+					     IOMMU_IOAS_MAP_WRITEABLE |       \
+					     IOMMU_IOAS_MAP_READABLE));       \
+	})
+
+#define test_err_ioctl_ioas_map_fixed(_errno, buffer, length, iova)           \
+	({                                                                    \
+		__u64 __iova = iova;                                          \
+		EXPECT_ERRNO(_errno,                                          \
+			     _test_ioctl_ioas_map(                            \
+				     self->fd, self->ioas_id, buffer, length, \
+				     &__iova,                                 \
+				     IOMMU_IOAS_MAP_FIXED_IOVA |              \
+					     IOMMU_IOAS_MAP_WRITEABLE |       \
+					     IOMMU_IOAS_MAP_READABLE));       \
+	})
+
+static int _test_ioctl_ioas_unmap(int fd, unsigned int ioas_id, uint64_t iova,
+				  size_t length, uint64_t *out_len)
+{
+	struct iommu_ioas_unmap cmd = {
+		.size = sizeof(cmd),
+		.ioas_id = ioas_id,
+		.iova = iova,
+		.length = length,
+	};
+	int ret;
+
+	ret = ioctl(fd, IOMMU_IOAS_UNMAP, &cmd);
+	if (out_len)
+		*out_len = cmd.length;
+	return ret;
+}
+#define test_ioctl_ioas_unmap(iova, length)                                \
+	ASSERT_EQ(0, _test_ioctl_ioas_unmap(self->fd, self->ioas_id, iova, \
+					    length, NULL))
+
+#define test_ioctl_ioas_unmap_id(ioas_id, iova, length)                      \
+	ASSERT_EQ(0, _test_ioctl_ioas_unmap(self->fd, ioas_id, iova, length, \
+					    NULL))
+
+#define test_err_ioctl_ioas_unmap(_errno, iova, length)                      \
+	EXPECT_ERRNO(_errno, _test_ioctl_ioas_unmap(self->fd, self->ioas_id, \
+						    iova, length, NULL))
+
+static int _test_ioctl_set_temp_memory_limit(int fd, unsigned int limit)
+{
+	struct iommu_test_cmd memlimit_cmd = {
+		.size = sizeof(memlimit_cmd),
+		.op = IOMMU_TEST_OP_SET_TEMP_MEMORY_LIMIT,
+		.memory_limit = { .limit = limit },
+	};
+
+	return ioctl(fd, _IOMMU_TEST_CMD(IOMMU_TEST_OP_SET_TEMP_MEMORY_LIMIT),
+		     &memlimit_cmd);
+}
+
+#define test_ioctl_set_temp_memory_limit(limit) \
+	ASSERT_EQ(0, _test_ioctl_set_temp_memory_limit(self->fd, limit))
+
+#define test_ioctl_set_default_memory_limit() \
+	test_ioctl_set_temp_memory_limit(65536)
+
+static void teardown_iommufd(int fd, struct __test_metadata *_metadata)
+{
+	struct iommu_test_cmd test_cmd = {
+		.size = sizeof(test_cmd),
+		.op = IOMMU_TEST_OP_MD_CHECK_REFS,
+		.check_refs = { .length = BUFFER_SIZE,
+				.uptr = (uintptr_t)buffer },
+	};
+
+	if (fd == -1)
+		return;
+
+	EXPECT_EQ(0, close(fd));
+
+	fd = open("/dev/iommu", O_RDWR);
+	EXPECT_NE(-1, fd);
+	EXPECT_EQ(0, ioctl(fd, _IOMMU_TEST_CMD(IOMMU_TEST_OP_MD_CHECK_REFS),
+			   &test_cmd));
+	EXPECT_EQ(0, close(fd));
+}
+
+#define EXPECT_ERRNO(expected_errno, cmd)         \
+	({                                        \
+		ASSERT_EQ(-1, cmd);               \
+		EXPECT_EQ(expected_errno, errno); \
+	})
+
+#endif