From: David Matlack <dmatlack@google.com>
To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-kselftest@vger.kernel.org
Cc: Alex Williamson <alex@shazbot.org>,
David Matlack <dmatlack@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Shuah Khan <shuah@kernel.org>
Subject: [PATCH 2/3] vfio: selftests: Skip tests when the IOMMU mode is not available
Date: Thu, 29 Oct 2026 22:17:09 +0000 [thread overview]
Message-ID: <20261029221710.1871112-3-dmatlack@google.com> (raw)
In-Reply-To: <20261029221710.1871112-1-dmatlack@google.com>
Skip tests when the IOMMU mode they need is not available on the current
system, instead of failing. Add iommu_mode_is_available() to check whether
a given IOMMU mode (or, if NULL, any IOMMU mode) is available, and
SKIP_IF_IOMMU_MODE_UNAVAILABLE() to skip a kselftest harness test if not.
On a kernel without iommufd, for example, all of the iommufd and
iommufd_compat test variants currently fail on an assert in iommu_init().
Skip them instead, with a message that explains why:
ok 33 vfio_pci_driver_test.iommufd.send_msi # SKIP IOMMU mode not available: iommufd
Use SKIP_IF_IOMMU_MODE_UNAVAILABLE() in all tests that run across multiple
IOMMU modes, and in the tests that let the library pick the mode by
passing NULL to iommu_init(). Also skip vfio_pci_driver_test, which calls
iommu_init() from main() to probe the device, if no IOMMU mode is
available.
Skip from the test via the kselftest harness's SKIP(), rather than from
within iommu_init() via ksft_exit_skip(). ksft_exit_skip() is not aware of
the harness, and so would emit a bogus "1..0 # SKIP" plan line in the
middle of the TAP output, and the harness would report the reason for the
skip as "unknown".
Signed-off-by: David Matlack <dmatlack@google.com>
---
.../vfio/lib/include/libvfio/iommu.h | 26 ++++++++++++++++++-
tools/testing/selftests/vfio/lib/iommu.c | 8 ++++++
.../vfio/vfio_dma_mapping_mmio_test.c | 2 ++
.../selftests/vfio/vfio_dma_mapping_test.c | 4 +++
.../vfio/vfio_pci_device_init_perf_test.c | 2 ++
.../selftests/vfio/vfio_pci_device_test.c | 4 +++
.../selftests/vfio/vfio_pci_driver_test.c | 7 +++++
.../selftests/vfio/vfio_pci_sriov_uapi_test.c | 4 +++
8 files changed, 56 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/vfio/lib/include/libvfio/iommu.h b/tools/testing/selftests/vfio/lib/include/libvfio/iommu.h
index fb0a681ecc72..04b0377a0f8f 100644
--- a/tools/testing/selftests/vfio/lib/include/libvfio/iommu.h
+++ b/tools/testing/selftests/vfio/lib/include/libvfio/iommu.h
@@ -32,11 +32,18 @@ struct iommu {
/*
* Pass NULL for iommu_mode to automatically pick the mode most likely to work
- * on the current system.
+ * on the current system. Use iommu_mode_is_available() to check that the mode
+ * is available before calling iommu_init(), e.g. to skip the test if not.
*/
struct iommu *iommu_init(const char *iommu_mode);
void iommu_cleanup(struct iommu *iommu);
+/*
+ * Returns true if the given IOMMU mode is usable on the current system. If
+ * iommu_mode is NULL, returns true if any IOMMU mode is usable.
+ */
+bool iommu_mode_is_available(const char *iommu_mode);
+
int __iommu_map(struct iommu *iommu, struct dma_region *region);
static inline void iommu_map(struct iommu *iommu, struct dma_region *region)
@@ -81,4 +88,21 @@ FIXTURE_VARIANT_ADD_IOMMU_MODE(iommufd_compat_type1, ##__VA_ARGS__); \
FIXTURE_VARIANT_ADD_IOMMU_MODE(iommufd_compat_type1v2, ##__VA_ARGS__); \
FIXTURE_VARIANT_ADD_IOMMU_MODE(iommufd, ##__VA_ARGS__)
+/*
+ * Skip the current kselftest harness test if the given IOMMU mode is not
+ * available on the current system, or if no IOMMU mode is available if
+ * _iommu_mode is NULL. Like SKIP(), statement is executed after marking the
+ * test as skipped (e.g. "return"), and this can be used anywhere SKIP() can be
+ * used.
+ */
+#define SKIP_IF_IOMMU_MODE_UNAVAILABLE(statement, _iommu_mode) do { \
+ const char *__iommu_mode = (_iommu_mode); \
+ \
+ if (!iommu_mode_is_available(__iommu_mode)) \
+ SKIP(statement, "%s%s", \
+ __iommu_mode ? "IOMMU mode not available: " : \
+ "No IOMMU mode is available", \
+ __iommu_mode ?: ""); \
+} while (0)
+
#endif /* SELFTESTS_VFIO_LIB_INCLUDE_LIBVFIO_IOMMU_H */
diff --git a/tools/testing/selftests/vfio/lib/iommu.c b/tools/testing/selftests/vfio/lib/iommu.c
index 535e6c7cf260..2c7cf6dc919a 100644
--- a/tools/testing/selftests/vfio/lib/iommu.c
+++ b/tools/testing/selftests/vfio/lib/iommu.c
@@ -107,6 +107,14 @@ static const struct iommu_mode *iommu_mode_lookup(const char *iommu_mode)
VFIO_FAIL("Unrecognized IOMMU mode: %s\n", iommu_mode);
}
+bool iommu_mode_is_available(const char *iommu_mode)
+{
+ if (!iommu_mode)
+ return iommu_mode_detect();
+
+ return iommu_mode_probe(iommu_mode_lookup(iommu_mode));
+}
+
int __iommu_hva2iova(struct iommu *iommu, void *vaddr, iova_t *iova)
{
struct dma_region *region;
diff --git a/tools/testing/selftests/vfio/vfio_dma_mapping_mmio_test.c b/tools/testing/selftests/vfio/vfio_dma_mapping_mmio_test.c
index d7f25ef77671..add7d3881930 100644
--- a/tools/testing/selftests/vfio/vfio_dma_mapping_mmio_test.c
+++ b/tools/testing/selftests/vfio/vfio_dma_mapping_mmio_test.c
@@ -64,6 +64,8 @@ FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES();
FIXTURE_SETUP(vfio_dma_mapping_mmio_test)
{
+ SKIP_IF_IOMMU_MODE_UNAVAILABLE(return, variant->iommu_mode);
+
self->iommu = iommu_init(variant->iommu_mode);
self->device = vfio_pci_device_init(device_bdf, self->iommu);
self->iova_allocator = iova_allocator_init(self->iommu);
diff --git a/tools/testing/selftests/vfio/vfio_dma_mapping_test.c b/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
index 7d0de8c79de1..e42170aecf6e 100644
--- a/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
+++ b/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
@@ -119,6 +119,8 @@ FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(anonymous_hugetlb_1gb, SZ_1G, MAP_HUGETLB |
FIXTURE_SETUP(vfio_dma_mapping_test)
{
+ SKIP_IF_IOMMU_MODE_UNAVAILABLE(return, variant->iommu_mode);
+
self->iommu = iommu_init(variant->iommu_mode);
self->device = vfio_pci_device_init(device_bdf, self->iommu);
self->iova_allocator = iova_allocator_init(self->iommu);
@@ -228,6 +230,8 @@ FIXTURE_SETUP(vfio_dma_map_limit_test)
iova_t last_iova;
u32 nranges;
+ SKIP_IF_IOMMU_MODE_UNAVAILABLE(return, variant->iommu_mode);
+
/*
* Over-allocate mmap by double the size to provide enough backing vaddr
* for overflow tests
diff --git a/tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c b/tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c
index e1a54e153cd3..8a98c86096be 100644
--- a/tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c
+++ b/tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c
@@ -44,6 +44,8 @@ FIXTURE_SETUP(vfio_pci_device_init_perf_test)
{
int i;
+ SKIP_IF_IOMMU_MODE_UNAVAILABLE(return, variant->iommu_mode);
+
self->iommu = iommu_init(variant->iommu_mode);
self->threads = calloc_assert(nr_devices, sizeof(self->threads[0]));
self->thread_args = calloc_assert(nr_devices, sizeof(self->thread_args[0]));
diff --git a/tools/testing/selftests/vfio/vfio_pci_device_test.c b/tools/testing/selftests/vfio/vfio_pci_device_test.c
index 59a7c1f71804..1b1baa1e1c85 100644
--- a/tools/testing/selftests/vfio/vfio_pci_device_test.c
+++ b/tools/testing/selftests/vfio/vfio_pci_device_test.c
@@ -29,6 +29,8 @@ FIXTURE(vfio_pci_device_test) {
FIXTURE_SETUP(vfio_pci_device_test)
{
+ SKIP_IF_IOMMU_MODE_UNAVAILABLE(return, NULL);
+
self->iommu = iommu_init(NULL);
self->device = vfio_pci_device_init(device_bdf, self->iommu);
}
@@ -121,6 +123,8 @@ FIXTURE_VARIANT_ADD(vfio_pci_irq_test, msix) {
FIXTURE_SETUP(vfio_pci_irq_test)
{
+ SKIP_IF_IOMMU_MODE_UNAVAILABLE(return, NULL);
+
self->iommu = iommu_init(NULL);
self->device = vfio_pci_device_init(device_bdf, self->iommu);
}
diff --git a/tools/testing/selftests/vfio/vfio_pci_driver_test.c b/tools/testing/selftests/vfio/vfio_pci_driver_test.c
index f8f99ee6bb1a..710f9e7684d9 100644
--- a/tools/testing/selftests/vfio/vfio_pci_driver_test.c
+++ b/tools/testing/selftests/vfio/vfio_pci_driver_test.c
@@ -80,6 +80,8 @@ FIXTURE_SETUP(vfio_pci_driver_test)
{
struct vfio_pci_driver *driver;
+ SKIP_IF_IOMMU_MODE_UNAVAILABLE(return, variant->iommu_mode);
+
self->iommu = iommu_init(variant->iommu_mode);
self->device = vfio_pci_device_init(device_bdf, self->iommu);
self->iova_allocator = iova_allocator_init(self->iommu);
@@ -270,6 +272,11 @@ int main(int argc, char *argv[])
{
device_bdf = vfio_selftests_get_bdf(&argc, argv);
+ if (!iommu_mode_is_available(NULL)) {
+ fprintf(stderr, "No IOMMU mode is available\n");
+ return KSFT_SKIP;
+ }
+
if (!device_has_selftests_driver(device_bdf)) {
fprintf(stderr, "No driver found for device %s\n", device_bdf);
return KSFT_SKIP;
diff --git a/tools/testing/selftests/vfio/vfio_pci_sriov_uapi_test.c b/tools/testing/selftests/vfio/vfio_pci_sriov_uapi_test.c
index f3a018b8699d..32a1e651c815 100644
--- a/tools/testing/selftests/vfio/vfio_pci_sriov_uapi_test.c
+++ b/tools/testing/selftests/vfio/vfio_pci_sriov_uapi_test.c
@@ -90,6 +90,8 @@ FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(null_uuid, NULL);
FIXTURE_SETUP(vfio_pci_sriov_uapi_test)
{
+ SKIP_IF_IOMMU_MODE_UNAVAILABLE(return, variant->iommu_mode);
+
self->iommu = iommu_init(variant->iommu_mode);
self->pf_token = UUID_1;
@@ -163,6 +165,8 @@ TEST(failed_second_open_does_not_clobber_token)
struct iommu *iommu;
int ret;
+ SKIP_IF_IOMMU_MODE_UNAVAILABLE(return, MODE_IOMMUFD);
+
iommu = iommu_init(MODE_IOMMUFD);
/* Create and bind PF using UUID_1 */
--
2.56.0.317.g454f8302e1-goog
next prev parent reply other threads:[~2026-10-29 22:17 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-29 22:17 [PATCH 0/3] vfio: selftests: Automatically detect the IOMMU mode David Matlack
2026-10-29 22:17 ` [PATCH 1/3] vfio: selftests: Automatically detect the IOMMU mode in iommu_init() David Matlack
2026-10-29 22:17 ` David Matlack [this message]
2026-10-29 22:17 ` [PATCH 3/3] KVM: selftests: Use VFIO selftests library to pick IOMMU mode in IRQ test David Matlack
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