[PATCH v4 0/4] Move io-pgtable-arm selftest to KUnit

[PATCH v4 0/4] Move io-pgtable-arm selftest to KUnit

[Mostafa Saleh]

This is a small series to clean up the io-pgtable-arm library.

The first patch is a small clean up to reduce the depedencies of the
test before moving it.

The second patch was originally part of the SMMUv3 KVM driver support[1],
which needed to factor out the kernel code from the io-pgtable-arm
library, and based on Jason’s suggestion this can be taken out as a
cleanup, and a step further to convert it to kunit.

The second patch just moves the code to a new file with no other changes,
so it can be easier to review with “--color-moved”

The third patch converts the sefltest to be modular, that is useful as
kunit can be a module and it can run anytime after boot.

The fourth patch registers the test using kunit, and converges some of
the APIs, some notes about that:

Granularity of tests:
---------------------
To make the series easier to review, the series changes the test to run in
kunit without making intrusive changes to the test itself.
It’s possible to refactor the tests to have smaller granularity (although
I think that would make it less efficient as we might create the same io-pgtable
config multiple times) and integrate them in kunit as multiple tests, that
change would be more intrusive, if you think that is the right approach,
I can add a couple of more patches re-writing the tests.

Other changes:
--------------
- Also, to make the test changes minimal, and the fail messages similar,
  “KUNIT_FAIL()” is used to fail all tests instead of using KUNIT specific
  assertions.

- Instead of using faux device, we rely on kunit_device_register()

- The WARN is removed when a test fails, as that doesn’t seem to be a pattern
  used with kunit.


You can find the instructions on how to run kunit in the last patch commit message.

A failure at the test with the new implementation look as
[  191.675985]     # arm_lpae_do_selftests: selftest: pgsize_bitmap 0x20010000, IAS 40 OAS 48
[  191.676057]     # arm_lpae_do_selftests: EXPECTATION FAILED at drivers/iommu/io-pgtable-arm-selftests.c:91
[  191.676087]     # arm_lpae_do_selftests: selftest: test failed for fmt idx 0


Main changes in v4:
- Remove one missed __init.
- Change the kconfig dependencies back as it broke ARM
https://lore.kernel.org/all/202509201819.f369wBHc-lkp@intel.com/

v3: https://lore.kernel.org/all/20250919133316.2741279-1-smostafa@google.com/

Main changes in v3:
-------------------
- Move back unused code
- Simplify printing based on Jason comments + some renames
- Collect Jasons Rb
v2: https://lore.kernel.org/all/20250917191143.3847487-1-smostafa@google.com/

Main changes in v2:
-------------------
- Make the test modular
v1: https://lore.kernel.org/linux-iommu/20250917140216.2199055-1-smostafa@google.com/

[1] https://lore.kernel.org/all/20250819215156.2494305-5-smostafa@google.com/

Mostafa Saleh (4):
  iommu/io-pgtable-arm: Simplify error prints for selftests
  iommu/io-pgtable-arm: Move selftests to a separate file
  iommu/io-pgtable-arm-selftests: Modularize the test
  iommu/io-pgtable-arm-selftests: Use KUnit

 drivers/iommu/Kconfig                    |  11 +-
 drivers/iommu/Makefile                   |   1 +
 drivers/iommu/io-pgtable-arm-selftests.c | 222 +++++++++++++++++++++++
 drivers/iommu/io-pgtable-arm.c           | 204 ---------------------
 4 files changed, 229 insertions(+), 209 deletions(-)
 create mode 100644 drivers/iommu/io-pgtable-arm-selftests.c


base-commit: 07e27ad16399afcd693be20211b0dfae63e0615f
-- 
2.51.0.534.gc79095c0ca-goog

[PATCH v4 1/4] iommu/io-pgtable-arm: Simplify error prints for selftests

[Mostafa Saleh]

At the moment, if the self test fails it prints a lot of information
about the page table (size, levels...) this requires access to many
internals, which has to be exposed in the next patch moving the
tests out.

Instead, we can simplify the print, using ias, oas, pgsize_bitmap
and fmt is enough to identify the failed case, and the rest can
be deduced from the code.

Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
 drivers/iommu/io-pgtable-arm.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 7e8e2216c294..00218af5d5f7 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -1299,14 +1299,10 @@ static const struct iommu_flush_ops dummy_tlb_ops __initconst = {
 
 static void __init arm_lpae_dump_ops(struct io_pgtable_ops *ops)
 {
-	struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
-	struct io_pgtable_cfg *cfg = &data->iop.cfg;
+	struct io_pgtable_cfg *cfg = &io_pgtable_ops_to_pgtable(ops)->cfg;
 
-	pr_err("cfg: pgsize_bitmap 0x%lx, ias %u-bit\n",
-		cfg->pgsize_bitmap, cfg->ias);
-	pr_err("data: %d levels, 0x%zx pgd_size, %u pg_shift, %u bits_per_level, pgd @ %p\n",
-		ARM_LPAE_MAX_LEVELS - data->start_level, ARM_LPAE_PGD_SIZE(data),
-		ilog2(ARM_LPAE_GRANULE(data)), data->bits_per_level, data->pgd);
+	pr_err("cfg: pgsize_bitmap 0x%lx, ias %u-bit oas %u-bit\n",
+		cfg->pgsize_bitmap, cfg->ias, cfg->oas);
 }
 
 #define __FAIL(ops, i)	({						\
-- 
2.51.0.534.gc79095c0ca-goog

Re: [PATCH v4 1/4] iommu/io-pgtable-arm: Simplify error prints for selftests

[Jason Gunthorpe]

On Mon, Sep 22, 2025 at 08:59:25AM +0000, Mostafa Saleh wrote:
> At the moment, if the self test fails it prints a lot of information
> about the page table (size, levels...) this requires access to many
> internals, which has to be exposed in the next patch moving the
> tests out.
> 
> Instead, we can simplify the print, using ias, oas, pgsize_bitmap
> and fmt is enough to identify the failed case, and the rest can
> be deduced from the code.
> 
> Signed-off-by: Mostafa Saleh <smostafa@google.com>
> ---
>  drivers/iommu/io-pgtable-arm.c | 10 +++-------
>  1 file changed, 3 insertions(+), 7 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason

Re: [PATCH v4 1/4] iommu/io-pgtable-arm: Simplify error prints for selftests

[Pranjal Shrivastava]

On Mon, Sep 22, 2025 at 08:59:25AM +0000, Mostafa Saleh wrote:
> At the moment, if the self test fails it prints a lot of information
> about the page table (size, levels...) this requires access to many
> internals, which has to be exposed in the next patch moving the
> tests out.
> 
> Instead, we can simplify the print, using ias, oas, pgsize_bitmap
> and fmt is enough to identify the failed case, and the rest can
> be deduced from the code.
> 
> Signed-off-by: Mostafa Saleh <smostafa@google.com>
> ---
>  drivers/iommu/io-pgtable-arm.c | 10 +++-------
>  1 file changed, 3 insertions(+), 7 deletions(-)
> 

Reviewed-by: Pranjal Shrivastava <praan@google.com>

[PATCH v4 2/4] iommu/io-pgtable-arm: Move selftests to a separate file

[Mostafa Saleh]

Clean up the io-pgtable-arm library by moving the selftests out.
Next the tests will be registered with kunit.

This is useful also to factor out kernel specific code out, so
it can compiled as part of the hypervisor object.

Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
 drivers/iommu/Makefile                   |   1 +
 drivers/iommu/io-pgtable-arm-selftests.c | 208 +++++++++++++++++++++++
 drivers/iommu/io-pgtable-arm.c           | 200 ----------------------
 3 files changed, 209 insertions(+), 200 deletions(-)
 create mode 100644 drivers/iommu/io-pgtable-arm-selftests.c

diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index 355294fa9033..5250a2eea13f 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_IOMMU_DMA) += dma-iommu.o
 obj-$(CONFIG_IOMMU_IO_PGTABLE) += io-pgtable.o
 obj-$(CONFIG_IOMMU_IO_PGTABLE_ARMV7S) += io-pgtable-arm-v7s.o
 obj-$(CONFIG_IOMMU_IO_PGTABLE_LPAE) += io-pgtable-arm.o
+obj-$(CONFIG_IOMMU_IO_PGTABLE_LPAE_SELFTEST) += io-pgtable-arm-selftests.o
 obj-$(CONFIG_IOMMU_IO_PGTABLE_DART) += io-pgtable-dart.o
 obj-$(CONFIG_IOMMU_IOVA) += iova.o
 obj-$(CONFIG_OF_IOMMU)	+= of_iommu.o
diff --git a/drivers/iommu/io-pgtable-arm-selftests.c b/drivers/iommu/io-pgtable-arm-selftests.c
new file mode 100644
index 000000000000..17f48216647c
--- /dev/null
+++ b/drivers/iommu/io-pgtable-arm-selftests.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * CPU-agnostic ARM page table allocator.
+ *
+ * Copyright (C) 2014 ARM Limited
+ *
+ * Author: Will Deacon <will.deacon@arm.com>
+ */
+#include <linux/device/faux.h>
+#include <linux/io-pgtable.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+
+#include "io-pgtable-arm.h"
+
+static struct io_pgtable_cfg *cfg_cookie __initdata;
+
+static void __init dummy_tlb_flush_all(void *cookie)
+{
+	WARN_ON(cookie != cfg_cookie);
+}
+
+static void __init dummy_tlb_flush(unsigned long iova, size_t size,
+				   size_t granule, void *cookie)
+{
+	WARN_ON(cookie != cfg_cookie);
+	WARN_ON(!(size & cfg_cookie->pgsize_bitmap));
+}
+
+static void __init dummy_tlb_add_page(struct iommu_iotlb_gather *gather,
+				      unsigned long iova, size_t granule,
+				      void *cookie)
+{
+	dummy_tlb_flush(iova, granule, granule, cookie);
+}
+
+static const struct iommu_flush_ops dummy_tlb_ops __initconst = {
+	.tlb_flush_all	= dummy_tlb_flush_all,
+	.tlb_flush_walk	= dummy_tlb_flush,
+	.tlb_add_page	= dummy_tlb_add_page,
+};
+
+static void __init arm_lpae_dump_ops(struct io_pgtable_ops *ops)
+{
+	struct io_pgtable_cfg *cfg = &io_pgtable_ops_to_pgtable(ops)->cfg;
+
+	pr_err("cfg: pgsize_bitmap 0x%lx, ias %u-bit oas %u-bit\n",
+		cfg->pgsize_bitmap, cfg->ias, cfg->oas);
+}
+
+#define __FAIL(ops, i)	({						\
+		WARN(1, "selftest: test failed for fmt idx %d\n", (i));	\
+		arm_lpae_dump_ops(ops);					\
+		-EFAULT;						\
+})
+
+static int __init arm_lpae_run_tests(struct io_pgtable_cfg *cfg)
+{
+	static const enum io_pgtable_fmt fmts[] __initconst = {
+		ARM_64_LPAE_S1,
+		ARM_64_LPAE_S2,
+	};
+
+	int i, j;
+	unsigned long iova;
+	size_t size, mapped;
+	struct io_pgtable_ops *ops;
+
+	for (i = 0; i < ARRAY_SIZE(fmts); ++i) {
+		cfg_cookie = cfg;
+		ops = alloc_io_pgtable_ops(fmts[i], cfg, cfg);
+		if (!ops) {
+			pr_err("selftest: failed to allocate io pgtable ops\n");
+			return -ENOMEM;
+		}
+
+		/*
+		 * Initial sanity checks.
+		 * Empty page tables shouldn't provide any translations.
+		 */
+		if (ops->iova_to_phys(ops, 42))
+			return __FAIL(ops, i);
+
+		if (ops->iova_to_phys(ops, SZ_1G + 42))
+			return __FAIL(ops, i);
+
+		if (ops->iova_to_phys(ops, SZ_2G + 42))
+			return __FAIL(ops, i);
+
+		/*
+		 * Distinct mappings of different granule sizes.
+		 */
+		iova = 0;
+		for_each_set_bit(j, &cfg->pgsize_bitmap, BITS_PER_LONG) {
+			size = 1UL << j;
+
+			if (ops->map_pages(ops, iova, iova, size, 1,
+					   IOMMU_READ | IOMMU_WRITE |
+					   IOMMU_NOEXEC | IOMMU_CACHE,
+					   GFP_KERNEL, &mapped))
+				return __FAIL(ops, i);
+
+			/* Overlapping mappings */
+			if (!ops->map_pages(ops, iova, iova + size, size, 1,
+					    IOMMU_READ | IOMMU_NOEXEC,
+					    GFP_KERNEL, &mapped))
+				return __FAIL(ops, i);
+
+			if (ops->iova_to_phys(ops, iova + 42) != (iova + 42))
+				return __FAIL(ops, i);
+
+			iova += SZ_1G;
+		}
+
+		/* Full unmap */
+		iova = 0;
+		for_each_set_bit(j, &cfg->pgsize_bitmap, BITS_PER_LONG) {
+			size = 1UL << j;
+
+			if (ops->unmap_pages(ops, iova, size, 1, NULL) != size)
+				return __FAIL(ops, i);
+
+			if (ops->iova_to_phys(ops, iova + 42))
+				return __FAIL(ops, i);
+
+			/* Remap full block */
+			if (ops->map_pages(ops, iova, iova, size, 1,
+					   IOMMU_WRITE, GFP_KERNEL, &mapped))
+				return __FAIL(ops, i);
+
+			if (ops->iova_to_phys(ops, iova + 42) != (iova + 42))
+				return __FAIL(ops, i);
+
+			iova += SZ_1G;
+		}
+
+		/*
+		 * Map/unmap the last largest supported page of the IAS, this can
+		 * trigger corner cases in the concatednated page tables.
+		 */
+		mapped = 0;
+		size = 1UL << __fls(cfg->pgsize_bitmap);
+		iova = (1UL << cfg->ias) - size;
+		if (ops->map_pages(ops, iova, iova, size, 1,
+				   IOMMU_READ | IOMMU_WRITE |
+				   IOMMU_NOEXEC | IOMMU_CACHE,
+				   GFP_KERNEL, &mapped))
+			return __FAIL(ops, i);
+		if (mapped != size)
+			return __FAIL(ops, i);
+		if (ops->unmap_pages(ops, iova, size, 1, NULL) != size)
+			return __FAIL(ops, i);
+
+		free_io_pgtable_ops(ops);
+	}
+
+	return 0;
+}
+
+static int __init arm_lpae_do_selftests(void)
+{
+	static const unsigned long pgsize[] __initconst = {
+		SZ_4K | SZ_2M | SZ_1G,
+		SZ_16K | SZ_32M,
+		SZ_64K | SZ_512M,
+	};
+
+	static const unsigned int address_size[] __initconst = {
+		32, 36, 40, 42, 44, 48,
+	};
+
+	int i, j, k, pass = 0, fail = 0;
+	struct faux_device *dev;
+	struct io_pgtable_cfg cfg = {
+		.tlb = &dummy_tlb_ops,
+		.coherent_walk = true,
+		.quirks = IO_PGTABLE_QUIRK_NO_WARN,
+	};
+
+	dev = faux_device_create("io-pgtable-test", NULL, 0);
+	if (!dev)
+		return -ENOMEM;
+
+	cfg.iommu_dev = &dev->dev;
+
+	for (i = 0; i < ARRAY_SIZE(pgsize); ++i) {
+		for (j = 0; j < ARRAY_SIZE(address_size); ++j) {
+			/* Don't use ias > oas as it is not valid for stage-2. */
+			for (k = 0; k <= j; ++k) {
+				cfg.pgsize_bitmap = pgsize[i];
+				cfg.ias = address_size[k];
+				cfg.oas = address_size[j];
+				pr_info("selftest: pgsize_bitmap 0x%08lx, IAS %u OAS %u\n",
+					pgsize[i], cfg.ias, cfg.oas);
+				if (arm_lpae_run_tests(&cfg))
+					fail++;
+				else
+					pass++;
+			}
+		}
+	}
+
+	pr_info("selftest: completed with %d PASS %d FAIL\n", pass, fail);
+	faux_device_destroy(dev);
+
+	return fail ? -EFAULT : 0;
+}
+subsys_initcall(arm_lpae_do_selftests);
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 00218af5d5f7..aed18b3d277f 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -12,10 +12,7 @@
 #include <linux/atomic.h>
 #include <linux/bitops.h>
 #include <linux/io-pgtable.h>
-#include <linux/kernel.h>
-#include <linux/device/faux.h>
 #include <linux/sizes.h>
-#include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/dma-mapping.h>
 
@@ -1267,200 +1264,3 @@ struct io_pgtable_init_fns io_pgtable_arm_mali_lpae_init_fns = {
 	.alloc	= arm_mali_lpae_alloc_pgtable,
 	.free	= arm_lpae_free_pgtable,
 };
-
-#ifdef CONFIG_IOMMU_IO_PGTABLE_LPAE_SELFTEST
-
-static struct io_pgtable_cfg *cfg_cookie __initdata;
-
-static void __init dummy_tlb_flush_all(void *cookie)
-{
-	WARN_ON(cookie != cfg_cookie);
-}
-
-static void __init dummy_tlb_flush(unsigned long iova, size_t size,
-				   size_t granule, void *cookie)
-{
-	WARN_ON(cookie != cfg_cookie);
-	WARN_ON(!(size & cfg_cookie->pgsize_bitmap));
-}
-
-static void __init dummy_tlb_add_page(struct iommu_iotlb_gather *gather,
-				      unsigned long iova, size_t granule,
-				      void *cookie)
-{
-	dummy_tlb_flush(iova, granule, granule, cookie);
-}
-
-static const struct iommu_flush_ops dummy_tlb_ops __initconst = {
-	.tlb_flush_all	= dummy_tlb_flush_all,
-	.tlb_flush_walk	= dummy_tlb_flush,
-	.tlb_add_page	= dummy_tlb_add_page,
-};
-
-static void __init arm_lpae_dump_ops(struct io_pgtable_ops *ops)
-{
-	struct io_pgtable_cfg *cfg = &io_pgtable_ops_to_pgtable(ops)->cfg;
-
-	pr_err("cfg: pgsize_bitmap 0x%lx, ias %u-bit oas %u-bit\n",
-		cfg->pgsize_bitmap, cfg->ias, cfg->oas);
-}
-
-#define __FAIL(ops, i)	({						\
-		WARN(1, "selftest: test failed for fmt idx %d\n", (i));	\
-		arm_lpae_dump_ops(ops);					\
-		-EFAULT;						\
-})
-
-static int __init arm_lpae_run_tests(struct io_pgtable_cfg *cfg)
-{
-	static const enum io_pgtable_fmt fmts[] __initconst = {
-		ARM_64_LPAE_S1,
-		ARM_64_LPAE_S2,
-	};
-
-	int i, j;
-	unsigned long iova;
-	size_t size, mapped;
-	struct io_pgtable_ops *ops;
-
-	for (i = 0; i < ARRAY_SIZE(fmts); ++i) {
-		cfg_cookie = cfg;
-		ops = alloc_io_pgtable_ops(fmts[i], cfg, cfg);
-		if (!ops) {
-			pr_err("selftest: failed to allocate io pgtable ops\n");
-			return -ENOMEM;
-		}
-
-		/*
-		 * Initial sanity checks.
-		 * Empty page tables shouldn't provide any translations.
-		 */
-		if (ops->iova_to_phys(ops, 42))
-			return __FAIL(ops, i);
-
-		if (ops->iova_to_phys(ops, SZ_1G + 42))
-			return __FAIL(ops, i);
-
-		if (ops->iova_to_phys(ops, SZ_2G + 42))
-			return __FAIL(ops, i);
-
-		/*
-		 * Distinct mappings of different granule sizes.
-		 */
-		iova = 0;
-		for_each_set_bit(j, &cfg->pgsize_bitmap, BITS_PER_LONG) {
-			size = 1UL << j;
-
-			if (ops->map_pages(ops, iova, iova, size, 1,
-					   IOMMU_READ | IOMMU_WRITE |
-					   IOMMU_NOEXEC | IOMMU_CACHE,
-					   GFP_KERNEL, &mapped))
-				return __FAIL(ops, i);
-
-			/* Overlapping mappings */
-			if (!ops->map_pages(ops, iova, iova + size, size, 1,
-					    IOMMU_READ | IOMMU_NOEXEC,
-					    GFP_KERNEL, &mapped))
-				return __FAIL(ops, i);
-
-			if (ops->iova_to_phys(ops, iova + 42) != (iova + 42))
-				return __FAIL(ops, i);
-
-			iova += SZ_1G;
-		}
-
-		/* Full unmap */
-		iova = 0;
-		for_each_set_bit(j, &cfg->pgsize_bitmap, BITS_PER_LONG) {
-			size = 1UL << j;
-
-			if (ops->unmap_pages(ops, iova, size, 1, NULL) != size)
-				return __FAIL(ops, i);
-
-			if (ops->iova_to_phys(ops, iova + 42))
-				return __FAIL(ops, i);
-
-			/* Remap full block */
-			if (ops->map_pages(ops, iova, iova, size, 1,
-					   IOMMU_WRITE, GFP_KERNEL, &mapped))
-				return __FAIL(ops, i);
-
-			if (ops->iova_to_phys(ops, iova + 42) != (iova + 42))
-				return __FAIL(ops, i);
-
-			iova += SZ_1G;
-		}
-
-		/*
-		 * Map/unmap the last largest supported page of the IAS, this can
-		 * trigger corner cases in the concatednated page tables.
-		 */
-		mapped = 0;
-		size = 1UL << __fls(cfg->pgsize_bitmap);
-		iova = (1UL << cfg->ias) - size;
-		if (ops->map_pages(ops, iova, iova, size, 1,
-				   IOMMU_READ | IOMMU_WRITE |
-				   IOMMU_NOEXEC | IOMMU_CACHE,
-				   GFP_KERNEL, &mapped))
-			return __FAIL(ops, i);
-		if (mapped != size)
-			return __FAIL(ops, i);
-		if (ops->unmap_pages(ops, iova, size, 1, NULL) != size)
-			return __FAIL(ops, i);
-
-		free_io_pgtable_ops(ops);
-	}
-
-	return 0;
-}
-
-static int __init arm_lpae_do_selftests(void)
-{
-	static const unsigned long pgsize[] __initconst = {
-		SZ_4K | SZ_2M | SZ_1G,
-		SZ_16K | SZ_32M,
-		SZ_64K | SZ_512M,
-	};
-
-	static const unsigned int address_size[] __initconst = {
-		32, 36, 40, 42, 44, 48,
-	};
-
-	int i, j, k, pass = 0, fail = 0;
-	struct faux_device *dev;
-	struct io_pgtable_cfg cfg = {
-		.tlb = &dummy_tlb_ops,
-		.coherent_walk = true,
-		.quirks = IO_PGTABLE_QUIRK_NO_WARN,
-	};
-
-	dev = faux_device_create("io-pgtable-test", NULL, 0);
-	if (!dev)
-		return -ENOMEM;
-
-	cfg.iommu_dev = &dev->dev;
-
-	for (i = 0; i < ARRAY_SIZE(pgsize); ++i) {
-		for (j = 0; j < ARRAY_SIZE(address_size); ++j) {
-			/* Don't use ias > oas as it is not valid for stage-2. */
-			for (k = 0; k <= j; ++k) {
-				cfg.pgsize_bitmap = pgsize[i];
-				cfg.ias = address_size[k];
-				cfg.oas = address_size[j];
-				pr_info("selftest: pgsize_bitmap 0x%08lx, IAS %u OAS %u\n",
-					pgsize[i], cfg.ias, cfg.oas);
-				if (arm_lpae_run_tests(&cfg))
-					fail++;
-				else
-					pass++;
-			}
-		}
-	}
-
-	pr_info("selftest: completed with %d PASS %d FAIL\n", pass, fail);
-	faux_device_destroy(dev);
-
-	return fail ? -EFAULT : 0;
-}
-subsys_initcall(arm_lpae_do_selftests);
-#endif
-- 
2.51.0.534.gc79095c0ca-goog

Re: [PATCH v4 2/4] iommu/io-pgtable-arm: Move selftests to a separate file

[Jason Gunthorpe]

On Mon, Sep 22, 2025 at 08:59:26AM +0000, Mostafa Saleh wrote:
> Clean up the io-pgtable-arm library by moving the selftests out.
> Next the tests will be registered with kunit.
> 
> This is useful also to factor out kernel specific code out, so
> it can compiled as part of the hypervisor object.
> 
> Signed-off-by: Mostafa Saleh <smostafa@google.com>
> ---
>  drivers/iommu/Makefile                   |   1 +
>  drivers/iommu/io-pgtable-arm-selftests.c | 208 +++++++++++++++++++++++
>  drivers/iommu/io-pgtable-arm.c           | 200 ----------------------
>  3 files changed, 209 insertions(+), 200 deletions(-)
>  create mode 100644 drivers/iommu/io-pgtable-arm-selftests.c

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason

Re: [PATCH v4 2/4] iommu/io-pgtable-arm: Move selftests to a separate file

[Pranjal Shrivastava]

On Mon, Sep 22, 2025 at 08:59:26AM +0000, Mostafa Saleh wrote:
> Clean up the io-pgtable-arm library by moving the selftests out.
> Next the tests will be registered with kunit.
> 
> This is useful also to factor out kernel specific code out, so
> it can compiled as part of the hypervisor object.
> 
> Signed-off-by: Mostafa Saleh <smostafa@google.com>
> ---
>  drivers/iommu/Makefile                   |   1 +
>  drivers/iommu/io-pgtable-arm-selftests.c | 208 +++++++++++++++++++++++
>  drivers/iommu/io-pgtable-arm.c           | 200 ----------------------
>  3 files changed, 209 insertions(+), 200 deletions(-)

Reviewed-by: Pranjal Shrivastava <praan@google.com>

[PATCH v4 3/4] iommu/io-pgtable-arm-selftests: Modularize the test

[Mostafa Saleh]

Remove the __init constraint, as the test will be converted to KUnit,
it can run on-demand after later.

Also, as KUnit can be a module, make this test modular.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
 drivers/iommu/Kconfig                    |  2 +-
 drivers/iommu/io-pgtable-arm-selftests.c | 36 +++++++++++++++---------
 2 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 70d29b14d851..553522ef3ca9 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -41,7 +41,7 @@ config IOMMU_IO_PGTABLE_LPAE
 	  up to 48-bits in size.
 
 config IOMMU_IO_PGTABLE_LPAE_SELFTEST
-	bool "LPAE selftests"
+	tristate "LPAE selftests"
 	depends on IOMMU_IO_PGTABLE_LPAE
 	help
 	  Enable self-tests for LPAE page table allocator. This performs
diff --git a/drivers/iommu/io-pgtable-arm-selftests.c b/drivers/iommu/io-pgtable-arm-selftests.c
index 17f48216647c..50350e88d9b4 100644
--- a/drivers/iommu/io-pgtable-arm-selftests.c
+++ b/drivers/iommu/io-pgtable-arm-selftests.c
@@ -13,34 +13,34 @@
 
 #include "io-pgtable-arm.h"
 
-static struct io_pgtable_cfg *cfg_cookie __initdata;
+static struct io_pgtable_cfg *cfg_cookie;
 
-static void __init dummy_tlb_flush_all(void *cookie)
+static void dummy_tlb_flush_all(void *cookie)
 {
 	WARN_ON(cookie != cfg_cookie);
 }
 
-static void __init dummy_tlb_flush(unsigned long iova, size_t size,
-				   size_t granule, void *cookie)
+static void dummy_tlb_flush(unsigned long iova, size_t size,
+			    size_t granule, void *cookie)
 {
 	WARN_ON(cookie != cfg_cookie);
 	WARN_ON(!(size & cfg_cookie->pgsize_bitmap));
 }
 
-static void __init dummy_tlb_add_page(struct iommu_iotlb_gather *gather,
-				      unsigned long iova, size_t granule,
-				      void *cookie)
+static void dummy_tlb_add_page(struct iommu_iotlb_gather *gather,
+			       unsigned long iova, size_t granule,
+			       void *cookie)
 {
 	dummy_tlb_flush(iova, granule, granule, cookie);
 }
 
-static const struct iommu_flush_ops dummy_tlb_ops __initconst = {
+static const struct iommu_flush_ops dummy_tlb_ops = {
 	.tlb_flush_all	= dummy_tlb_flush_all,
 	.tlb_flush_walk	= dummy_tlb_flush,
 	.tlb_add_page	= dummy_tlb_add_page,
 };
 
-static void __init arm_lpae_dump_ops(struct io_pgtable_ops *ops)
+static void arm_lpae_dump_ops(struct io_pgtable_ops *ops)
 {
 	struct io_pgtable_cfg *cfg = &io_pgtable_ops_to_pgtable(ops)->cfg;
 
@@ -54,9 +54,9 @@ static void __init arm_lpae_dump_ops(struct io_pgtable_ops *ops)
 		-EFAULT;						\
 })
 
-static int __init arm_lpae_run_tests(struct io_pgtable_cfg *cfg)
+static int arm_lpae_run_tests(struct io_pgtable_cfg *cfg)
 {
-	static const enum io_pgtable_fmt fmts[] __initconst = {
+	static const enum io_pgtable_fmt fmts[] = {
 		ARM_64_LPAE_S1,
 		ARM_64_LPAE_S2,
 	};
@@ -157,15 +157,15 @@ static int __init arm_lpae_run_tests(struct io_pgtable_cfg *cfg)
 	return 0;
 }
 
-static int __init arm_lpae_do_selftests(void)
+static int arm_lpae_do_selftests(void)
 {
-	static const unsigned long pgsize[] __initconst = {
+	static const unsigned long pgsize[] = {
 		SZ_4K | SZ_2M | SZ_1G,
 		SZ_16K | SZ_32M,
 		SZ_64K | SZ_512M,
 	};
 
-	static const unsigned int address_size[] __initconst = {
+	static const unsigned int address_size[] = {
 		32, 36, 40, 42, 44, 48,
 	};
 
@@ -205,4 +205,12 @@ static int __init arm_lpae_do_selftests(void)
 
 	return fail ? -EFAULT : 0;
 }
+
+static void arm_lpae_exit_selftests(void)
+{
+}
+
 subsys_initcall(arm_lpae_do_selftests);
+module_exit(arm_lpae_exit_selftests);
+MODULE_DESCRIPTION("io-pgtable-arm library selftest");
+MODULE_LICENSE("GPL");
-- 
2.51.0.534.gc79095c0ca-goog

Re: [PATCH v4 3/4] iommu/io-pgtable-arm-selftests: Modularize the test

[Pranjal Shrivastava]

On Mon, Sep 22, 2025 at 08:59:27AM +0000, Mostafa Saleh wrote:
> Remove the __init constraint, as the test will be converted to KUnit,
> it can run on-demand after later.
> 
> Also, as KUnit can be a module, make this test modular.
> 
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Mostafa Saleh <smostafa@google.com>
> ---
>  drivers/iommu/Kconfig                    |  2 +-
>  drivers/iommu/io-pgtable-arm-selftests.c | 36 +++++++++++++++---------
>  2 files changed, 23 insertions(+), 15 deletions(-)
> 

Reviewed-by: Pranjal Shrivastava <praan@google.com>

[PATCH v4 4/4] iommu/io-pgtable-arm-selftests: Use KUnit

[Mostafa Saleh]

Integrate the selftests as part of kunit.

Now instead of the test only being run at boot, it can run:

- With CONFIG_IOMMU_IO_PGTABLE_LPAE_KUNIT_TEST=y
  It will automatically run at boot as before.

- Otherwise with CONFIG_IOMMU_IO_PGTABLE_KUNIT_TEST=m:
  1) on module load:
     Once the module load the self test will run
     # modprobe io-pgtable-arm-selftests

  2) debugfs
     With CONFIG_KUNIT_DEBUGFS=y You can run the test with
     # echo 1 > /sys/kernel/debug/kunit/io-pgtable-arm-test/run

  3) Using kunit.py
     You can also use the helper script which uses Qemu in the background

     # ./tools/testing/kunit/kunit.py run --build_dir build_kunit_arm64 --arch arm64 \
       --make_options LLVM=1 --kunitconfig ./kunit/kunitconfig
      [18:01:09] ============= io-pgtable-arm-test (1 subtest) ==============
      [18:01:09] [PASSED] arm_lpae_do_selftests
      [18:01:09] =============== [PASSED] io-pgtable-arm-test ===============
      [18:01:09] ============================================================

Suggested-by: Jason Gunthorpe <jgg@ziepe.ca>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
 drivers/iommu/Kconfig                    | 11 ++--
 drivers/iommu/Makefile                   |  2 +-
 drivers/iommu/io-pgtable-arm-selftests.c | 82 +++++++++++++-----------
 3 files changed, 51 insertions(+), 44 deletions(-)

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 553522ef3ca9..d50685433347 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -40,12 +40,13 @@ config IOMMU_IO_PGTABLE_LPAE
 	  sizes at both stage-1 and stage-2, as well as address spaces
 	  up to 48-bits in size.
 
-config IOMMU_IO_PGTABLE_LPAE_SELFTEST
-	tristate "LPAE selftests"
-	depends on IOMMU_IO_PGTABLE_LPAE
+config IOMMU_IO_PGTABLE_LPAE_KUNIT_TEST
+	tristate "KUnit tests for LPAE"
+	depends on IOMMU_IO_PGTABLE_LPAE && KUNIT
+	default KUNIT_ALL_TESTS
 	help
-	  Enable self-tests for LPAE page table allocator. This performs
-	  a series of page-table consistency checks during boot.
+	  Enable kunit tests for LPAE page table allocator. This performs
+	  a series of page-table consistency checks.
 
 	  If unsure, say N here.
 
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index 5250a2eea13f..ac3851570303 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -12,7 +12,7 @@ obj-$(CONFIG_IOMMU_DMA) += dma-iommu.o
 obj-$(CONFIG_IOMMU_IO_PGTABLE) += io-pgtable.o
 obj-$(CONFIG_IOMMU_IO_PGTABLE_ARMV7S) += io-pgtable-arm-v7s.o
 obj-$(CONFIG_IOMMU_IO_PGTABLE_LPAE) += io-pgtable-arm.o
-obj-$(CONFIG_IOMMU_IO_PGTABLE_LPAE_SELFTEST) += io-pgtable-arm-selftests.o
+obj-$(CONFIG_IOMMU_IO_PGTABLE_LPAE_KUNIT_TEST) += io-pgtable-arm-selftests.o
 obj-$(CONFIG_IOMMU_IO_PGTABLE_DART) += io-pgtable-dart.o
 obj-$(CONFIG_IOMMU_IOVA) += iova.o
 obj-$(CONFIG_OF_IOMMU)	+= of_iommu.o
diff --git a/drivers/iommu/io-pgtable-arm-selftests.c b/drivers/iommu/io-pgtable-arm-selftests.c
index 50350e88d9b4..fc18bd54a315 100644
--- a/drivers/iommu/io-pgtable-arm-selftests.c
+++ b/drivers/iommu/io-pgtable-arm-selftests.c
@@ -6,7 +6,8 @@
  *
  * Author: Will Deacon <will.deacon@arm.com>
  */
-#include <linux/device/faux.h>
+#include <kunit/device.h>
+#include <kunit/test.h>
 #include <linux/io-pgtable.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
@@ -48,13 +49,14 @@ static void arm_lpae_dump_ops(struct io_pgtable_ops *ops)
 		cfg->pgsize_bitmap, cfg->ias, cfg->oas);
 }
 
-#define __FAIL(ops, i)	({						\
-		WARN(1, "selftest: test failed for fmt idx %d\n", (i));	\
-		arm_lpae_dump_ops(ops);					\
-		-EFAULT;						\
+#define __FAIL(test, ops, i)	({						\
+		KUNIT_FAIL(test, "");						\
+		kunit_err(test, "selftest: test failed for fmt idx %d\n", (i));	\
+		arm_lpae_dump_ops(ops);						\
+		-EFAULT;							\
 })
 
-static int arm_lpae_run_tests(struct io_pgtable_cfg *cfg)
+static int arm_lpae_run_tests(struct kunit *test, struct io_pgtable_cfg *cfg)
 {
 	static const enum io_pgtable_fmt fmts[] = {
 		ARM_64_LPAE_S1,
@@ -70,7 +72,7 @@ static int arm_lpae_run_tests(struct io_pgtable_cfg *cfg)
 		cfg_cookie = cfg;
 		ops = alloc_io_pgtable_ops(fmts[i], cfg, cfg);
 		if (!ops) {
-			pr_err("selftest: failed to allocate io pgtable ops\n");
+			kunit_err(test, "selftest: failed to allocate io pgtable ops\n");
 			return -ENOMEM;
 		}
 
@@ -79,13 +81,13 @@ static int arm_lpae_run_tests(struct io_pgtable_cfg *cfg)
 		 * Empty page tables shouldn't provide any translations.
 		 */
 		if (ops->iova_to_phys(ops, 42))
-			return __FAIL(ops, i);
+			return __FAIL(test, ops, i);
 
 		if (ops->iova_to_phys(ops, SZ_1G + 42))
-			return __FAIL(ops, i);
+			return __FAIL(test, ops, i);
 
 		if (ops->iova_to_phys(ops, SZ_2G + 42))
-			return __FAIL(ops, i);
+			return __FAIL(test, ops, i);
 
 		/*
 		 * Distinct mappings of different granule sizes.
@@ -98,16 +100,16 @@ static int arm_lpae_run_tests(struct io_pgtable_cfg *cfg)
 					   IOMMU_READ | IOMMU_WRITE |
 					   IOMMU_NOEXEC | IOMMU_CACHE,
 					   GFP_KERNEL, &mapped))
-				return __FAIL(ops, i);
+				return __FAIL(test, ops, i);
 
 			/* Overlapping mappings */
 			if (!ops->map_pages(ops, iova, iova + size, size, 1,
 					    IOMMU_READ | IOMMU_NOEXEC,
 					    GFP_KERNEL, &mapped))
-				return __FAIL(ops, i);
+				return __FAIL(test, ops, i);
 
 			if (ops->iova_to_phys(ops, iova + 42) != (iova + 42))
-				return __FAIL(ops, i);
+				return __FAIL(test, ops, i);
 
 			iova += SZ_1G;
 		}
@@ -118,18 +120,18 @@ static int arm_lpae_run_tests(struct io_pgtable_cfg *cfg)
 			size = 1UL << j;
 
 			if (ops->unmap_pages(ops, iova, size, 1, NULL) != size)
-				return __FAIL(ops, i);
+				return __FAIL(test, ops, i);
 
 			if (ops->iova_to_phys(ops, iova + 42))
-				return __FAIL(ops, i);
+				return __FAIL(test, ops, i);
 
 			/* Remap full block */
 			if (ops->map_pages(ops, iova, iova, size, 1,
 					   IOMMU_WRITE, GFP_KERNEL, &mapped))
-				return __FAIL(ops, i);
+				return __FAIL(test, ops, i);
 
 			if (ops->iova_to_phys(ops, iova + 42) != (iova + 42))
-				return __FAIL(ops, i);
+				return __FAIL(test, ops, i);
 
 			iova += SZ_1G;
 		}
@@ -145,11 +147,11 @@ static int arm_lpae_run_tests(struct io_pgtable_cfg *cfg)
 				   IOMMU_READ | IOMMU_WRITE |
 				   IOMMU_NOEXEC | IOMMU_CACHE,
 				   GFP_KERNEL, &mapped))
-			return __FAIL(ops, i);
+			return __FAIL(test, ops, i);
 		if (mapped != size)
-			return __FAIL(ops, i);
+			return __FAIL(test, ops, i);
 		if (ops->unmap_pages(ops, iova, size, 1, NULL) != size)
-			return __FAIL(ops, i);
+			return __FAIL(test, ops, i);
 
 		free_io_pgtable_ops(ops);
 	}
@@ -157,7 +159,7 @@ static int arm_lpae_run_tests(struct io_pgtable_cfg *cfg)
 	return 0;
 }
 
-static int arm_lpae_do_selftests(void)
+static void arm_lpae_do_selftests(struct kunit *test)
 {
 	static const unsigned long pgsize[] = {
 		SZ_4K | SZ_2M | SZ_1G,
@@ -170,18 +172,19 @@ static int arm_lpae_do_selftests(void)
 	};
 
 	int i, j, k, pass = 0, fail = 0;
-	struct faux_device *dev;
+	struct device *dev;
 	struct io_pgtable_cfg cfg = {
 		.tlb = &dummy_tlb_ops,
 		.coherent_walk = true,
 		.quirks = IO_PGTABLE_QUIRK_NO_WARN,
 	};
 
-	dev = faux_device_create("io-pgtable-test", NULL, 0);
-	if (!dev)
-		return -ENOMEM;
+	dev = kunit_device_register(test, "io-pgtable-test");
+	KUNIT_EXPECT_NOT_ERR_OR_NULL(test, dev);
+	if (IS_ERR_OR_NULL(dev))
+		return;
 
-	cfg.iommu_dev = &dev->dev;
+	cfg.iommu_dev = dev;
 
 	for (i = 0; i < ARRAY_SIZE(pgsize); ++i) {
 		for (j = 0; j < ARRAY_SIZE(address_size); ++j) {
@@ -190,9 +193,9 @@ static int arm_lpae_do_selftests(void)
 				cfg.pgsize_bitmap = pgsize[i];
 				cfg.ias = address_size[k];
 				cfg.oas = address_size[j];
-				pr_info("selftest: pgsize_bitmap 0x%08lx, IAS %u OAS %u\n",
-					pgsize[i], cfg.ias, cfg.oas);
-				if (arm_lpae_run_tests(&cfg))
+				kunit_info(test, "selftest: pgsize_bitmap 0x%08lx, IAS %u OAS %u\n",
+					   pgsize[i], cfg.ias, cfg.oas);
+				if (arm_lpae_run_tests(test, &cfg))
 					fail++;
 				else
 					pass++;
@@ -200,17 +203,20 @@ static int arm_lpae_do_selftests(void)
 		}
 	}
 
-	pr_info("selftest: completed with %d PASS %d FAIL\n", pass, fail);
-	faux_device_destroy(dev);
-
-	return fail ? -EFAULT : 0;
+	kunit_info(test, "selftest: completed with %d PASS %d FAIL\n", pass, fail);
 }
 
-static void arm_lpae_exit_selftests(void)
-{
-}
+static struct kunit_case io_pgtable_arm_test_cases[] = {
+	KUNIT_CASE(arm_lpae_do_selftests),
+	{},
+};
+
+static struct kunit_suite io_pgtable_arm_test = {
+	.name = "io-pgtable-arm-test",
+	.test_cases = io_pgtable_arm_test_cases,
+};
+
+kunit_test_suite(io_pgtable_arm_test);
 
-subsys_initcall(arm_lpae_do_selftests);
-module_exit(arm_lpae_exit_selftests);
 MODULE_DESCRIPTION("io-pgtable-arm library selftest");
 MODULE_LICENSE("GPL");
-- 
2.51.0.534.gc79095c0ca-goog

Re: [PATCH v4 4/4] iommu/io-pgtable-arm-selftests: Use KUnit

[Pranjal Shrivastava]

On Mon, Sep 22, 2025 at 08:59:28AM +0000, Mostafa Saleh wrote:
> Integrate the selftests as part of kunit.
> 
> Now instead of the test only being run at boot, it can run:
> 
> - With CONFIG_IOMMU_IO_PGTABLE_LPAE_KUNIT_TEST=y
>   It will automatically run at boot as before.
> 
> - Otherwise with CONFIG_IOMMU_IO_PGTABLE_KUNIT_TEST=m:
>   1) on module load:
>      Once the module load the self test will run
>      # modprobe io-pgtable-arm-selftests
> 
>   2) debugfs
>      With CONFIG_KUNIT_DEBUGFS=y You can run the test with
>      # echo 1 > /sys/kernel/debug/kunit/io-pgtable-arm-test/run
> 
>   3) Using kunit.py
>      You can also use the helper script which uses Qemu in the background
> 
>      # ./tools/testing/kunit/kunit.py run --build_dir build_kunit_arm64 --arch arm64 \
>        --make_options LLVM=1 --kunitconfig ./kunit/kunitconfig
>       [18:01:09] ============= io-pgtable-arm-test (1 subtest) ==============
>       [18:01:09] [PASSED] arm_lpae_do_selftests
>       [18:01:09] =============== [PASSED] io-pgtable-arm-test ===============
>       [18:01:09] ============================================================
> 
> Suggested-by: Jason Gunthorpe <jgg@ziepe.ca>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Mostafa Saleh <smostafa@google.com>
> ---
>  drivers/iommu/Kconfig                    | 11 ++--
>  drivers/iommu/Makefile                   |  2 +-
>  drivers/iommu/io-pgtable-arm-selftests.c | 82 +++++++++++++-----------
>  3 files changed, 51 insertions(+), 44 deletions(-)
> 

Reviewed-by: Pranjal Shrivastava <praan@google.com>

Moving the io-pgtable selftests out of the main driver code and
the integration with the KUnit framework looks good to me.

I was able to apply, build and test the series with multiple configs on
QEMU virt. 

   # arm_lpae_do_selftests: selftest: pgsize_bitmap 0x20010000, IAS 40 OAS 44
   # arm_lpae_do_selftests: selftest: pgsize_bitmap 0x20010000, IAS 42 OAS 44
   # arm_lpae_do_selftests: selftest: pgsize_bitmap 0x20010000, IAS 44 OAS 44
   # arm_lpae_do_selftests: selftest: pgsize_bitmap 0x20010000, IAS 32 OAS 48
   # arm_lpae_do_selftests: selftest: pgsize_bitmap 0x20010000, IAS 36 OAS 48
   # arm_lpae_do_selftests: selftest: pgsize_bitmap 0x20010000, IAS 40 OAS 48
   # arm_lpae_do_selftests: selftest: pgsize_bitmap 0x20010000, IAS 42 OAS 48
   # arm_lpae_do_selftests: selftest: pgsize_bitmap 0x20010000, IAS 44 OAS 48
   # arm_lpae_do_selftests: selftest: pgsize_bitmap 0x20010000, IAS 48 OAS 48
   # arm_lpae_do_selftests: selftest: completed with 63 PASS 0 FAIL
   ok 1 arm_lpae_do_selftests
 ok 1 io-pgtable-arm-test

Thanks,
Praan