vfio: selftests: Add tests to validate SR-IOV UAPI

Add a selftest, vfio_pci_sriov_uapi_test.c, to validate the
SR-IOV UAPI, including the following cases, iterating over
all the IOMMU modes currently supported:
 - Setting correct/incorrect/NULL tokens during device init.
 - Close the PF device immediately after setting the token.
 - Change/override the PF's token after device init.

Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Reviewed-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Tested-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20260505212838.1698034-9-rananta@google.com
Signed-off-by: Alex Williamson <alex@shazbot.org>

tools/testing/selftests/vfio/Makefile

@@ -12,6 +12,7 @@ TEST_GEN_PROGS += vfio_iommufd_setup_test
 TEST_GEN_PROGS += vfio_pci_device_test
 TEST_GEN_PROGS += vfio_pci_device_init_perf_test
 TEST_GEN_PROGS += vfio_pci_driver_test
+TEST_GEN_PROGS += vfio_pci_sriov_uapi_test
 
 TEST_FILES += scripts/cleanup.sh
 TEST_FILES += scripts/lib.sh

tools/testing/selftests/vfio/vfio_pci_sriov_uapi_test.c

@@ -0,0 +1,217 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include "lib/include/libvfio/assert.h"
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <linux/limits.h>
+
+#include <libvfio.h>
+
+#include "../kselftest_harness.h"
+
+#define UUID_1 "52ac9bff-3a88-4fbd-901a-0d767c3b6c97"
+#define UUID_2 "88594674-90a0-47a9-aea8-9d9b352ac08a"
+
+static const char *pf_bdf;
+static char *vf_bdf;
+
+static pid_t main_pid;
+
+static int container_setup(struct vfio_pci_device *device, const char *bdf,
+			   const char *vf_token)
+{
+	vfio_pci_group_setup(device, bdf);
+	vfio_container_set_iommu(device);
+	__vfio_pci_group_get_device_fd(device, bdf, vf_token);
+
+	/* The device fd will be -1 in case of mismatched tokens */
+	return (device->fd < 0);
+}
+
+static int iommufd_setup(struct vfio_pci_device *device, const char *bdf,
+			 const char *vf_token)
+{
+	vfio_pci_cdev_open(device, bdf);
+	return __vfio_device_bind_iommufd(device->fd,
+					  device->iommu->iommufd, vf_token);
+}
+
+static int device_init(const char *bdf, struct iommu *iommu,
+		       const char *vf_token, struct vfio_pci_device **out_dev)
+{
+	struct vfio_pci_device *device = vfio_pci_device_alloc(bdf, iommu);
+	int ret;
+
+	if (iommu->mode->container_path)
+		ret = container_setup(device, bdf, vf_token);
+	else
+		ret = iommufd_setup(device, bdf, vf_token);
+
+	*out_dev = device;
+	return ret;
+}
+
+static void device_cleanup(struct vfio_pci_device *device)
+{
+	if (!device)
+		return;
+
+	if (device->fd > 0)
+		VFIO_ASSERT_EQ(close(device->fd), 0);
+
+	if (device->group_fd)
+		VFIO_ASSERT_EQ(close(device->group_fd), 0);
+
+	vfio_pci_device_free(device);
+}
+
+FIXTURE(vfio_pci_sriov_uapi_test) {
+	struct vfio_pci_device *pf;
+	struct vfio_pci_device *vf;
+	struct iommu *iommu;
+	char *pf_token;
+};
+
+FIXTURE_VARIANT(vfio_pci_sriov_uapi_test) {
+	const char *iommu_mode;
+	char *vf_token;
+};
+
+#define FIXTURE_VARIANT_ADD_IOMMU_MODE(_iommu_mode, _name, _vf_token)		\
+FIXTURE_VARIANT_ADD(vfio_pci_sriov_uapi_test, _iommu_mode ## _ ## _name) {	\
+	.iommu_mode = #_iommu_mode,						\
+	.vf_token = (_vf_token),						\
+}
+
+FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(same_uuid, UUID_1);
+FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(diff_uuid, UUID_2);
+FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(null_uuid, NULL);
+
+FIXTURE_SETUP(vfio_pci_sriov_uapi_test)
+{
+	self->iommu = iommu_init(variant->iommu_mode);
+
+	self->pf_token = UUID_1;
+	ASSERT_EQ(device_init(pf_bdf, self->iommu, self->pf_token, &self->pf), 0);
+}
+
+FIXTURE_TEARDOWN(vfio_pci_sriov_uapi_test)
+{
+	device_cleanup(self->vf);
+	device_cleanup(self->pf);
+	iommu_cleanup(self->iommu);
+}
+
+/*
+ * This asserts if the VF device is successfully created if its token matches
+ * with the token used to create/override the PF or fails during a mismatch.
+ */
+#define ASSERT_COND_VF_CREATION(_ret) do {					\
+	if (!variant->vf_token || strcmp(self->pf_token, variant->vf_token)) {	\
+		ASSERT_NE((_ret), 0);						\
+	} else {								\
+		ASSERT_EQ((_ret), 0);						\
+	}									\
+} while (0)
+
+/*
+ * Validate if the UAPI handles correctly and incorrectly set token on the VF.
+ */
+TEST_F(vfio_pci_sriov_uapi_test, init_token_match)
+{
+	int ret;
+
+	ret = device_init(vf_bdf, self->iommu, variant->vf_token, &self->vf);
+	ASSERT_COND_VF_CREATION(ret);
+}
+
+/*
+ * After closing the PF, validate if the VF access still needs the right token.
+ */
+TEST_F(vfio_pci_sriov_uapi_test, pf_early_close)
+{
+	int ret;
+
+	device_cleanup(self->pf);
+
+	/* Clean the 'pf' to avoid calling device_cleanup() again. */
+	self->pf = NULL;
+
+	ret = device_init(vf_bdf, self->iommu, variant->vf_token, &self->vf);
+	ASSERT_COND_VF_CREATION(ret);
+}
+
+/*
+ * After PF device init, override the existing token and validate if the newly
+ * set token is the one that's active.
+ */
+TEST_F(vfio_pci_sriov_uapi_test, override_token)
+{
+	int ret;
+
+	self->pf_token = UUID_2;
+	vfio_device_set_vf_token(self->pf->fd, self->pf_token);
+
+	ret = device_init(vf_bdf, self->iommu, variant->vf_token, &self->vf);
+	ASSERT_COND_VF_CREATION(ret);
+}
+
+static void vf_teardown(void)
+{
+	/*
+	 * The child processes, created by TEST_F()s, inherits this atexit()
+	 * handler. Hence, check and destroy the VF only when the main/parent
+	 * process exits.
+	 */
+	if (getpid() != main_pid)
+		return;
+
+	free(vf_bdf);
+	sysfs_sriov_numvfs_set(pf_bdf, 0);
+}
+
+static void vf_setup(void)
+{
+	char *vf_driver;
+	int nr_vfs;
+
+	nr_vfs = sysfs_sriov_totalvfs_get(pf_bdf);
+	if (nr_vfs <= 0)
+		ksft_exit_skip("SR-IOV may not be supported by the PF: %s\n", pf_bdf);
+
+	nr_vfs = sysfs_sriov_numvfs_get(pf_bdf);
+	if (nr_vfs != 0)
+		ksft_exit_skip("SR-IOV already configured for the PF: %s\n", pf_bdf);
+
+	/* Create only one VF for testing */
+	sysfs_sriov_numvfs_set(pf_bdf, 1);
+
+	/*
+	 * Setup an exit handler to destroy the VF in case of failures
+	 * during further setup at the end of the test run.
+	 */
+	main_pid = getpid();
+	VFIO_ASSERT_EQ(atexit(vf_teardown), 0);
+
+	vf_bdf = sysfs_sriov_vf_bdf_get(pf_bdf, 0);
+
+	/*
+	 * The VF inherits the driver from the PF.
+	 * Ensure this is 'vfio-pci' before proceeding.
+	 */
+	vf_driver = sysfs_driver_get(vf_bdf);
+	VFIO_ASSERT_NE(vf_driver, NULL);
+	VFIO_ASSERT_EQ(strcmp(vf_driver, "vfio-pci"), 0);
+	free(vf_driver);
+
+	printf("Created 1 VF (%s) under the PF: %s\n", vf_bdf, pf_bdf);
+}
+
+int main(int argc, char *argv[])
+{
+	pf_bdf = vfio_selftests_get_bdf(&argc, argv);
+	vf_setup();
+
+	return test_harness_run(argc, argv);
+}