Re: [PATCH v6 3/6] x86/e820: Refactor range_update and range_remove

From: Martin Fernandez
Date: Fri Mar 04 2022 - 15:34:06 EST

On 2/7/22, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> Something I think would be really amazing here is if you could add KUnit
> tests here to exercise the corner cases and validate the changes. It
> should be pretty easy to add. Here's a quick example for the boilerplate
> and testing a bit of __e820__range_add():
>
> #ifdef CONFIG_E820_KUNIT_TEST
> #include <kunit/test.h>
>
> static void __init test_e820_range_add(struct kunit *context)
> {
> struct e820_table table;
> u32 full;
>
> full = ARRAY_SIZE(table.entries);
> /* Add last entry. */
> table->nr_entries = full - 1;
> __e820__range_add(&table, 0, 15, 0);
> KUNIT_EXPECT_EQ(table->nr_entries, full)
> /* Skip new entry when full. */
> __e820__range_add(&table, 0, 15, 0);
> KUNIT_EXPECT_EQ(table->nr_entries, full)
> }
>
> static void __init test_e820_update(struct kunit *context)
> {
> ...
> }
>
> static struct kunit_case __refdata e820_test_cases[] = {
> KUNIT_CASE(test_e820_range_add),
> KUNIT_CASE(test_e820_update),
> ...
> {}
> };
>
> static struct kunit_suite e820_test_suite = {
> .name = "e820",
> .test_cases = e820_test_cases,
> };
>
> kunit_test_suites(&e820_test_suite);
> #endif

I almost got it. Although when added the tests I have a warning
when compiling, because KUnit doens't want to deal with __init things:

WARNING: modpost: vmlinux.o(.data+0x26800): Section mismatch in
reference from the variable __UNIQUE_ID_array286 to the variable
.init.data:e820_test_suite
The variable __UNIQUE_ID_array286 references
the variable __initdata e820_test_suite
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

I need to test __init functions. I couldn't find any other similar
cases in existant code. Is there a nice way to solve this?

I'm adding the file that contains the tests just in case..


#include <kunit/test.h>

#include <asm/e820/api.h>
#include <asm/setup.h>

#define KUNIT_EXPECT_E820_ENTRY_EQ(test, entry, _addr, _size, _type, \
_crypto_capable) \
do { \
KUNIT_EXPECT_EQ((test), (entry).addr, (_addr)); \
KUNIT_EXPECT_EQ((test), (entry).size, (_size)); \
KUNIT_EXPECT_EQ((test), (entry).type, (_type)); \
KUNIT_EXPECT_EQ((test), (entry).crypto_capable, \
(_crypto_capable)); \
} while (0)

struct e820_table test_table __initdata;

static void __init test_e820_range_add(struct kunit *test)
{
u32 full;

full = ARRAY_SIZE(test_table.entries);
/* Add last entry. */
test_table.nr_entries = full - 1;
__e820__range_add(&test_table, 0, 15, 0, 0);
KUNIT_EXPECT_EQ(test, test_table.nr_entries, full);
/* Skip new entry when full. */
__e820__range_add(&test_table, 0, 15, 0, 0);
KUNIT_EXPECT_EQ(test, test_table.nr_entries, full);
}

static void __init test_e820_range_update(struct kunit *test)
{
u64 entry_size = 15;
u64 updated_size = 0;
/* Initialize table */
test_table.nr_entries = 0;
__e820__range_add(&test_table, 0, entry_size, E820_TYPE_RAM,
E820_NOT_CRYPTO_CAPABLE);
__e820__range_add(&test_table, entry_size, entry_size, E820_TYPE_RAM,
E820_NOT_CRYPTO_CAPABLE);
__e820__range_add(&test_table, entry_size * 2, entry_size,
E820_TYPE_ACPI, E820_NOT_CRYPTO_CAPABLE);

updated_size = __e820__range_update(&test_table, 0, entry_size * 2,
E820_TYPE_RAM, E820_TYPE_RESERVED);
/* The first 2 regions were updated */
KUNIT_EXPECT_EQ(test, updated_size, entry_size * 2);
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[0], 0, entry_size,
E820_TYPE_RESERVED, E820_NOT_CRYPTO_CAPABLE);
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[1], entry_size,
entry_size, E820_TYPE_RESERVED,
E820_NOT_CRYPTO_CAPABLE);
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[2], entry_size * 2,
entry_size, E820_TYPE_ACPI,
E820_NOT_CRYPTO_CAPABLE);

updated_size = __e820__range_update(&test_table, 0, entry_size * 3,
E820_TYPE_RESERVED, E820_TYPE_RAM);
/* Only the first 2 regions were updated */
KUNIT_EXPECT_EQ(test, updated_size, entry_size * 2);
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[0], 0, entry_size,
E820_TYPE_RAM, E820_NOT_CRYPTO_CAPABLE);
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[1], entry_size,
entry_size, E820_TYPE_RAM,
E820_NOT_CRYPTO_CAPABLE);
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[2], entry_size * 2,
entry_size, E820_TYPE_ACPI,
E820_NOT_CRYPTO_CAPABLE);
}

static void __init test_e820_range_remove(struct kunit *test)
{
u64 entry_size = 15;
u64 removed_size = 0;

struct e820_entry_updater updater = {
.should_update = remover__should_update,
.update = remover__update,
.new = remover__new
};

struct e820_remover_data data = {
.check_type = true,
.old_type = E820_TYPE_RAM
};

/* Initialize table */
test_table.nr_entries = 0;
__e820__range_add(&test_table, 0, entry_size, E820_TYPE_RAM,
E820_NOT_CRYPTO_CAPABLE);
__e820__range_add(&test_table, entry_size, entry_size, E820_TYPE_RAM,
E820_NOT_CRYPTO_CAPABLE);
__e820__range_add(&test_table, entry_size * 2, entry_size,
E820_TYPE_ACPI, E820_NOT_CRYPTO_CAPABLE);

/*
* Need to use __e820__handle_range_update because
* e820__range_remove doesn't ask for the table
*/
removed_size = __e820__handle_range_update(&test_table,
0, entry_size * 2,
&updater, &data);
/* The first two regions were removed */
KUNIT_EXPECT_EQ(test, removed_size, entry_size * 2);
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[0], 0, 0, 0, 0);
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[1], 0, 0, 0, 0);

removed_size = __e820__handle_range_update(&test_table,
0, entry_size * 3,
&updater, &data);
/* Nothing was removed */
KUNIT_EXPECT_EQ(test, removed_size, 0);
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[0], 0, 0, 0, 0);
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[1], 0, 0, 0, 0);
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[2], entry_size * 2,
entry_size, E820_TYPE_ACPI,
E820_NOT_CRYPTO_CAPABLE);
}

static void __init test_e820_range_crypto_update(struct kunit *test)
{
u64 entry_size = 15;
u64 updated_size = 0;
/* Initialize table */
test_table.nr_entries = 0;
__e820__range_add(&test_table, 0, entry_size, E820_TYPE_RAM,
E820_CRYPTO_CAPABLE);
__e820__range_add(&test_table, entry_size, entry_size, E820_TYPE_RAM,
E820_NOT_CRYPTO_CAPABLE);
__e820__range_add(&test_table, entry_size * 2, entry_size,
E820_TYPE_RAM, E820_CRYPTO_CAPABLE);

updated_size = __e820__range_update_crypto(&test_table, 0, entry_size * 3,
E820_CRYPTO_CAPABLE);
/* Only the region in the middle was updated */
KUNIT_EXPECT_EQ(test, updated_size, entry_size);
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[0], 0, entry_size,
E820_TYPE_RAM, E820_CRYPTO_CAPABLE);
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[1], entry_size,
entry_size, E820_TYPE_RAM,
E820_CRYPTO_CAPABLE);
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[2], entry_size * 2,
entry_size, E820_TYPE_RAM,
E820_CRYPTO_CAPABLE);
}

static void __init test_e820_handle_range_update_intersection(struct
kunit *test)
{
struct e820_entry_updater updater = {
.should_update = type_updater__should_update,
.update = type_updater__update,
.new = type_updater__new
};

struct e820_type_updater_data data = {
.old_type = E820_TYPE_RAM,
.new_type = E820_TYPE_RESERVED
};

u64 entry_size = 15;
u64 updated_size = 0;
/* Initialize table */
test_table.nr_entries = 0;
__e820__range_add(&test_table, 0, entry_size, E820_TYPE_RAM,
E820_NOT_CRYPTO_CAPABLE);

updated_size = __e820__handle_range_update(&test_table,
0, entry_size - 2,
&updater, &data);

KUNIT_EXPECT_EQ(test, updated_size, entry_size - 2);

/* There is a new entry */
KUNIT_EXPECT_EQ(test, test_table.nr_entries, 2);

/* The original entry now is moved */
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[0], entry_size - 2,
2, E820_TYPE_RAM, E820_NOT_CRYPTO_CAPABLE);

/* The new entry has the correct values */
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[1], 0, 13,
E820_TYPE_RESERVED, E820_NOT_CRYPTO_CAPABLE);
}

static void __init test_e820_handle_range_update_inside(struct kunit *test)
{
struct e820_entry_updater updater = {
.should_update = type_updater__should_update,
.update = type_updater__update,
.new = type_updater__new
};

struct e820_type_updater_data data = {
.old_type = E820_TYPE_RAM,
.new_type = E820_TYPE_RESERVED
};

u64 entry_size = 15;
u64 updated_size = 0;
/* Initialize table */
test_table.nr_entries = 0;
__e820__range_add(&test_table, 0, entry_size, E820_TYPE_RAM,
E820_NOT_CRYPTO_CAPABLE);

updated_size = __e820__handle_range_update(&test_table,
5, entry_size - 10,
&updater, &data);

KUNIT_EXPECT_EQ(test, updated_size, entry_size - 10);

/* There are two new entrie */
KUNIT_EXPECT_EQ(test, test_table.nr_entries, 3);

/* The original entry now shrinked */
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[0], 0, 5,
E820_TYPE_RAM, E820_NOT_CRYPTO_CAPABLE);

/* The new entries have the correct values */
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[1], 5,
entry_size - 10, E820_TYPE_RESERVED,
E820_NOT_CRYPTO_CAPABLE);
/* Left over of the original region */
KUNIT_EXPECT_E820_ENTRY_EQ(test, test_table.entries[2], entry_size - 5,
5, E820_TYPE_RAM, E820_NOT_CRYPTO_CAPABLE);
}

static struct kunit_case e820_test_cases[] __initdata = {
KUNIT_CASE(test_e820_range_add),
KUNIT_CASE(test_e820_range_update),
KUNIT_CASE(test_e820_range_remove),
KUNIT_CASE(test_e820_range_crypto_update),
KUNIT_CASE(test_e820_handle_range_update_intersection),
KUNIT_CASE(test_e820_handle_range_update_inside),
{}
};

static struct kunit_suite e820_test_suite __initdata = {
.name = "e820",
.test_cases = e820_test_cases,
};

kunit_test_suite(e820_test_suite);