[PATCH i-g-t v4 2/2] tests/intel/xe_fault_injection: Inject errors during xe_guc_ct_send_recv

[Satyanarayana K V P <satyanarayana.k.v.p@intel.com>]

Use the kernel fault injection infrastructure to test error handling
of xe at enabling of VFs stage when executing xe_guc_ct_send_recv()
so that more code paths are tested, such as error handling and unwinding.

Error can be injected using:
igt@xe_fault_injection@enable-vfs-fail-xe_guc_ct_send_recv

v2: Updated guc_fail_* to enable_vfs_*
Added igt_skip_on(!igt_sriov_is_pf(fd)) to skip test when run without
enabling sriov.

v3: Fixed documentation build error
ERROR: Missing documentation for igt@xe_fault_injection@enable-vfs-fail-xe_guc_ct_send_recv
ERROR: Unneeded documentation for igt@xe_fault_injection@guc-fail-xe_guc_ct_send_recv

v4: Fixed review comments.
Updated igt_skip_on to igt_require.

Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Michał Wajdeczko <michal.wajdeczko@intel.com>
Cc: Francois Dugast <francois.dugast@intel.com>
Signed-off-by: Satyanarayana K V P <satyanarayana.k.v.p@intel.com>
Reviewed-by: Francois Dugast <francois.dugast@intel.com>
Reviewed-by: Marcin Bernatowicz <marcin.bernatowicz@linux.intel.com>
---
 tests/intel/xe_fault_injection.c | 62 ++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/tests/intel/xe_fault_injection.c b/tests/intel/xe_fault_injection.c
index 3a0e2aa29..f92f955cd 100644
--- a/tests/intel/xe_fault_injection.c
+++ b/tests/intel/xe_fault_injection.c
@@ -19,12 +19,14 @@
 #include "igt_sysfs.h"
 #include "lib/igt_syncobj.h"
 #include "lib/intel_pat.h"
+#include "lib/igt_sriov_device.h"
 #include "xe/xe_ioctl.h"
 #include "xe/xe_query.h"
 
 #define INJECT_ERRNO	-ENOMEM
 #define BO_ADDR		0x1a0000
 #define BO_SIZE		(1024*1024)
+#define NUM_VFS		1
 
 enum injection_list_action {
 	INJECTION_LIST_ADD,
@@ -281,6 +283,55 @@ vm_bind_fail(int fd, const char function_name[])
 	igt_assert_eq(simple_vm_bind(fd, vm), 0);
 }
 
+static int sriov_enable_vfs(int fd, int num_vfs)
+{
+	int sysfs;
+	bool ret;
+
+	sysfs = igt_sysfs_open(fd);
+	igt_assert_fd(sysfs);
+
+	ret = __igt_sysfs_set_u32(sysfs, "device/sriov_numvfs", num_vfs);
+	close(sysfs);
+
+	return ret;
+}
+
+/**
+ * SUBTEST: enable-vfs-fail-%s
+ * Description: inject an error in function %arg[1] used when xe interacts with guc to make it fail
+ * Functionality: fault
+ *
+ * arg[1]:
+ * @xe_guc_ct_send_recv:               xe_guc_ct_send_recv
+ */
+
+static void
+enable_vfs_fail(int fd, int num_vfs, const char function_name[])
+{
+	bool autoprobe = 0;
+
+	ignore_faults_in_dmesg(function_name);
+	injection_list_do(INJECTION_LIST_ADD, function_name);
+	set_retval(function_name, INJECT_ERRNO);
+
+	autoprobe = igt_sriov_is_driver_autoprobe_enabled(fd);
+
+	if (autoprobe)
+		igt_sriov_disable_driver_autoprobe(fd);
+
+	/* igt_sriov_enable_vfs can't be used here as it is causing abort on any error.
+	 * Since error in this test is expected, we have written our own static function here.
+	 */
+	sriov_enable_vfs(fd, num_vfs);
+
+	igt_assert_eq(-errno, INJECT_ERRNO);
+	injection_list_do(INJECTION_LIST_REMOVE, function_name);
+
+	if (autoprobe)
+		igt_sriov_enable_driver_autoprobe(fd);
+}
+
 igt_main
 {
 	int fd;
@@ -319,6 +370,10 @@ igt_main
 		{ "xe_vma_ops_alloc" },
 		{ }
 	};
+	const struct section enable_vfs_fail_functions[] = {
+		{ "xe_guc_ct_send_recv" },
+		{ }
+	};
 
 	igt_fixture {
 		igt_require(fail_function_injection_enabled());
@@ -335,6 +390,13 @@ igt_main
 		igt_subtest_f("vm-bind-fail-%s", s->name)
 			vm_bind_fail(fd, s->name);
 
+	for (const struct section *s = enable_vfs_fail_functions; s->name; s++)
+		igt_subtest_f("enable-vfs-fail-%s", s->name) {
+			/* Skip the test if not running with SRIOV */
+			igt_require(igt_sriov_is_pf(fd));
+			enable_vfs_fail(fd, NUM_VFS, s->name);
+		}
+
 	igt_fixture {
 		xe_sysfs_driver_do(fd, pci_slot, XE_SYSFS_DRIVER_UNBIND);
 	}
-- 
2.35.3