[PATCH v10 1/2] selftests/vfio: Add NO_SEND_MSI feature flag and MSI helper macros

Rubin Du
2026-03-25T21:43:35Z

Add a features bitmask to struct vfio_pci_driver and define
VFIO_PCI_DRIVER_F_NO_SEND_MSI for drivers that cannot trigger MSI
interrupts via send_msi(). Drivers that lack MSI support opt-in by
setting this flag in their init() callback.

Change vfio_pci_driver_send_msi() to return int, checking the flag
internally and returning -EOPNOTSUPP when set.

Add fcntl_set_msi_nonblock(self) and update ASSERT_NO_MSI(self)
to check the flag internally.

Signed-off-by: Rubin Du <rubind@nvidia.com>
---
.../lib/include/libvfio/vfio_pci_driver.h | 5 ++-
.../selftests/vfio/lib/vfio_pci_driver.c | 6 ++-
.../selftests/vfio/vfio_pci_driver_test.c | 41 +++++++++++--------
3 files changed, 33 insertions(+), 19 deletions(-)

diff --git a/tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_driver.h b/tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_driver.h
index e5ada209b1d1..f2cf2608f757 100644
--- a/tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_driver.h
+++ b/tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_driver.h
@@ -6,6 +6,8 @@

struct vfio_pci_device;

+#define VFIO_PCI_DRIVER_F_NO_SEND_MSI (1UL << 0) /* Device cannot trigger MSI */
+
struct vfio_pci_driver_ops {
const char *name;

@@ -69,6 +71,7 @@ struct vfio_pci_driver {
const struct vfio_pci_driver_ops *ops;
bool initialized;
bool memcpy_in_progress;
+ unsigned long features;

/* Region to be used by the driver (e.g. for in-memory descriptors) */
struct dma_region region;
@@ -92,6 +95,6 @@ void vfio_pci_driver_memcpy_start(struct vfio_pci_device *device,
iova_t src, iova_t dst, u64 size,
u64 count);
int vfio_pci_driver_memcpy_wait(struct vfio_pci_device *device);
-void vfio_pci_driver_send_msi(struct vfio_pci_device *device);
+int vfio_pci_driver_send_msi(struct vfio_pci_device *device);

#endif /* SELFTESTS_VFIO_LIB_INCLUDE_LIBVFIO_VFIO_PCI_DRIVER_H */
diff --git a/tools/testing/selftests/vfio/lib/vfio_pci_driver.c b/tools/testing/selftests/vfio/lib/vfio_pci_driver.c
index 6827f4a6febe..b72df578717a 100644
--- a/tools/testing/selftests/vfio/lib/vfio_pci_driver.c
+++ b/tools/testing/selftests/vfio/lib/vfio_pci_driver.c
@@ -67,13 +67,17 @@ void vfio_pci_driver_remove(struct vfio_pci_device *device)
driver->initialized = false;
}

-void vfio_pci_driver_send_msi(struct vfio_pci_device *device)
+int vfio_pci_driver_send_msi(struct vfio_pci_device *device)
{
struct vfio_pci_driver *driver = &device->driver;

+ if (driver->features & VFIO_PCI_DRIVER_F_NO_SEND_MSI)
+ return -EOPNOTSUPP;
+
VFIO_CHECK_DRIVER_OP(driver, send_msi);

driver->ops->send_msi(device);
+ return 0;
}

void vfio_pci_driver_memcpy_start(struct vfio_pci_device *device,
diff --git a/tools/testing/selftests/vfio/vfio_pci_driver_test.c b/tools/testing/selftests/vfio/vfio_pci_driver_test.c
index afa0480ddd9b..491ac631b108 100644
--- a/tools/testing/selftests/vfio/vfio_pci_driver_test.c
+++ b/tools/testing/selftests/vfio/vfio_pci_driver_test.c
@@ -11,11 +11,18 @@

static const char *device_bdf;

-#define ASSERT_NO_MSI(_eventfd) do { \
- u64 __value; \
- \
- ASSERT_EQ(-1, read(_eventfd, &__value, 8)); \
- ASSERT_EQ(EAGAIN, errno); \
+#define fcntl_set_msi_nonblock(_self) do { \
+ if (!(_self->device->driver.features & VFIO_PCI_DRIVER_F_NO_SEND_MSI)) \
+ fcntl_set_nonblock(_self->msi_fd); \
+} while (0)
+
+#define ASSERT_NO_MSI(_self) do { \
+ u64 __value; \
+ \
+ if (_self->device->driver.features & VFIO_PCI_DRIVER_F_NO_SEND_MSI) \
+ break; \
+ ASSERT_EQ(-1, read(_self->msi_fd, &__value, 8)); \
+ ASSERT_EQ(EAGAIN, errno); \
} while (0)

static void region_setup(struct iommu *iommu,
@@ -129,7 +136,7 @@ TEST_F(vfio_pci_driver_test, init_remove)

TEST_F(vfio_pci_driver_test, memcpy_success)
{
- fcntl_set_nonblock(self->msi_fd);
+ fcntl_set_msi_nonblock(self);

memset(self->src, 'x', self->size);
memset(self->dst, 'y', self->size);
@@ -140,12 +147,12 @@ TEST_F(vfio_pci_driver_test, memcpy_success)
self->size));

ASSERT_EQ(0, memcmp(self->src, self->dst, self->size));
- ASSERT_NO_MSI(self->msi_fd);
+ ASSERT_NO_MSI(self);
}

TEST_F(vfio_pci_driver_test, memcpy_from_unmapped_iova)
{
- fcntl_set_nonblock(self->msi_fd);
+ fcntl_set_msi_nonblock(self);

/*
* Ignore the return value since not all devices will detect and report
@@ -153,13 +160,12 @@ TEST_F(vfio_pci_driver_test, memcpy_from_unmapped_iova)
*/
vfio_pci_driver_memcpy(self->device, self->unmapped_iova,
self->dst_iova, self->size);
-
- ASSERT_NO_MSI(self->msi_fd);
+ ASSERT_NO_MSI(self);
}

TEST_F(vfio_pci_driver_test, memcpy_to_unmapped_iova)
{
- fcntl_set_nonblock(self->msi_fd);
+ fcntl_set_msi_nonblock(self);

/*
* Ignore the return value since not all devices will detect and report
@@ -167,15 +173,15 @@ TEST_F(vfio_pci_driver_test, memcpy_to_unmapped_iova)
*/
vfio_pci_driver_memcpy(self->device, self->src_iova,
self->unmapped_iova, self->size);
-
- ASSERT_NO_MSI(self->msi_fd);
+ ASSERT_NO_MSI(self);
}

TEST_F(vfio_pci_driver_test, send_msi)
{
u64 value;

- vfio_pci_driver_send_msi(self->device);
+ if (vfio_pci_driver_send_msi(self->device))
+ SKIP(return, "Device does not support MSI\n");
ASSERT_EQ(8, read(self->msi_fd, &value, 8));
ASSERT_EQ(1, value);
}
@@ -201,7 +207,8 @@ TEST_F(vfio_pci_driver_test, mix_and_match)
self->dst_iova,
self->size);

- vfio_pci_driver_send_msi(self->device);
+ if (vfio_pci_driver_send_msi(self->device))
+ continue;
ASSERT_EQ(8, read(self->msi_fd, &value, 8));
ASSERT_EQ(1, value);
}
@@ -213,7 +220,7 @@ TEST_F_TIMEOUT(vfio_pci_driver_test, memcpy_storm, 60)
u64 total_size;
u64 count;

- fcntl_set_nonblock(self->msi_fd);
+ fcntl_set_msi_nonblock(self);

/*
* Perform up to 250GiB worth of DMA reads and writes across several
@@ -230,7 +237,7 @@ TEST_F_TIMEOUT(vfio_pci_driver_test, memcpy_storm, 60)
self->size, count);

ASSERT_EQ(0, vfio_pci_driver_memcpy_wait(self->device));
- ASSERT_NO_MSI(self->msi_fd);
+ ASSERT_NO_MSI(self);
}

static bool device_has_selftests_driver(const char *bdf)
--
2.43.0