vfio: selftests: Add test to reset vfio device.

Add a test to vfio_pci_device_test which resets the device. If reset is
not supported by the device, the test is skipped.

Signed-off-by: Josh Hilke <jrhilke@google.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20250822212518.4156428-7-dmatlack@google.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

tools/testing/selftests/vfio/lib/include/vfio_util.h

@@ -83,6 +83,7 @@ const char *vfio_selftests_get_bdf(int *argc, char *argv[]);
 
 struct vfio_pci_device *vfio_pci_device_init(const char *bdf, int iommu_type);
 void vfio_pci_device_cleanup(struct vfio_pci_device *device);
+void vfio_pci_device_reset(struct vfio_pci_device *device);
 
 void vfio_pci_dma_map(struct vfio_pci_device *device, u64 iova, u64 size,
 		      void *vaddr);

tools/testing/selftests/vfio/lib/vfio_pci_device.c

@@ -202,6 +202,11 @@ void vfio_pci_config_access(struct vfio_pci_device *device, bool write,
 		       write ? "write to" : "read from", config);
 }
 
+void vfio_pci_device_reset(struct vfio_pci_device *device)
+{
+	ioctl_assert(device->fd, VFIO_DEVICE_RESET, NULL);
+}
+
 static unsigned int vfio_pci_get_group_from_dev(const char *bdf)
 {
 	char dev_iommu_group_path[PATH_MAX] = {0};

tools/testing/selftests/vfio/vfio_pci_device_test.c

@@ -155,6 +155,14 @@ TEST_F(vfio_pci_irq_test, enable_trigger_disable)
 	vfio_pci_irq_disable(self->device, variant->irq_index);
 }
 
+TEST_F(vfio_pci_device_test, reset)
+{
+	if (!(self->device->info.flags & VFIO_DEVICE_FLAGS_RESET))
+		SKIP(return, "Device does not support reset\n");
+
+	vfio_pci_device_reset(self->device);
+}
+
 int main(int argc, char *argv[])
 {
 	device_bdf = vfio_selftests_get_bdf(&argc, argv);