[i-g-t,v4,2/3] tests/intel/xe_fault_injection: Inject errors during xe_guc_ct_send_recv & xe_guc_mmio_send_recv.
K V P, Satyanarayana
satyanarayana.k.v.p at intel.com
Fri Apr 4 06:04:59 UTC 2025
> From: Laguna, Lukasz <lukasz.laguna at intel.com>
> Sent: Thursday, April 3, 2025 7:05 PM
> To: K V P, Satyanarayana <satyanarayana.k.v.p at intel.com>; igt-
> dev at lists.freedesktop.org
> Cc: De Marchi, Lucas <lucas.demarchi at intel.com>; Wajdeczko, Michal
> <Michal.Wajdeczko at intel.com>; Dugast, Francois
> <francois.dugast at intel.com>
> Subject: Re: [i-g-t,v4,2/3] tests/intel/xe_fault_injection: Inject errors during
> xe_guc_ct_send_recv & xe_guc_mmio_send_recv.
>
>
> On 3/28/2025 12:15, Satyanarayana K V P wrote:
> > Use the kernel fault injection infrastructure to test error handling
> > of xe during driver probe when executing xe_guc_ct_send_recv() /
> > xe_guc_mmio_send_recv() so that more code paths are tested, such as
> > error handling and unwinding.
> >
> > All xe_init() kind of functions are called just once during driver probe,
> > so it is sufficient to fail first/all calls to them. Driver communicates
> > with the GuC multiple times, and the real failure can happen at different
> > call, hence the need to inject failure in GuC communication functions,
> > like guc_mmio_send() or guc_ct_send(), but it can't be just first call or
> > all calls, but we need to be able to select specific iteration to fail.
> >
> > To address this problem, the environmental variable
> IGT_FAULT_INJECT_ITERATION
>
> I think it'd be better to use test parameter instead of environment
> variable. Please check igt_main_args() and consider using it.
>
Hi Lukasz,
The intention of test is to inject error 0-100 iterations for guc_ct and guc_mmio functions.
The environment variable is used to inject error at specific iteration in case we want to debug
Issue in case of any failure. So, not used test parameter.
-Satya.
> > is used. If the IGT_FAULT_INJECT_ITERATION is not exported, an error will
> > be injected in every possible function call starting from first up to the
> > max number of iteration defined by INJECT_ITERATIONS, currently
> hardcoded
> > as 100. Also, using IGT_FAULT_INJECT_ITERATION, an error can be injected
> at
> > specific function call.
> >
> > Error can be injected using:
> > igt at xe_fault_injection@probe-fail-guc-xe_guc_ct_send_recv
> > igt at xe_fault_injection@probe-fail-guc-xe_guc_mmio_send_recv
> >
> > Signed-off-by: Satyanarayana K V P <satyanarayana.k.v.p at intel.com>
> > Cc: MichaĆ Wajdeczko <michal.wajdeczko at intel.com>
> > Cc: Francois Dugast <francois.dugast at intel.com>
> > Reviewed-by: Lucas De Marchi <lucas.demarchi at intel.com>
> > ---
> > tests/intel/xe_fault_injection.c | 61
> ++++++++++++++++++++++++++++++++
> > 1 file changed, 61 insertions(+)
> >
> > diff --git a/tests/intel/xe_fault_injection.c b/tests/intel/xe_fault_injection.c
> > index 1325a1716..a49070b4d 100644
> > --- a/tests/intel/xe_fault_injection.c
> > +++ b/tests/intel/xe_fault_injection.c
> > @@ -26,6 +26,7 @@
> > #define INJECT_ERRNO -ENOMEM
> > #define BO_ADDR 0x1a0000
> > #define BO_SIZE (1024*1024)
> > +#define INJECT_ITERATIONS 100
> >
> > enum injection_list_action {
> > INJECTION_LIST_ADD,
> > @@ -43,6 +44,24 @@ struct fault_injection_params {
> > uint32_t space;
> > };
> >
> > +/**
> > + * Introduce a new environmental variable IGT_FAULT_INJECT_ITERATION
> > + * using which an error can be injected at specific function call.
> > + * When unset test will run for INJECT_ITERATIONS iterations.
> > + * When set to <=0 or malformed - same as unset.
> > + * When set to >0 it will run single n-th iteration only.
> > + */
> > +static int get_fault_inject_iter(void)
> > +{
> > + const char *env = getenv("IGT_FAULT_INJECT_ITERATION");
> > +
> > + /* Return 0 if not exported / -ve value */
> > + if (!env || atoi(env) <= 0)
> > + return 0;
> > +
> > + return atoi(env);
> > +}
> > +
> > static int fail_function_open(void)
> > {
> > int debugfs_fail_function_dir_fd;
> > @@ -228,6 +247,34 @@ inject_fault_probe(int fd, char pci_slot[], const
> char function_name[])
> > injection_list_do(INJECTION_LIST_REMOVE, function_name);
> > }
> >
> > +/**
> > + * SUBTEST: probe-fail-guc-%s
> > + * Description: inject an error in the injectable function %arg[1] then
> reprobe driver
> > + * Functionality: fault
> > + *
> > + * arg[1]:
> > + * @xe_guc_mmio_send_recv: Inject an error when calling
> xe_guc_mmio_send_recv
> > + * @xe_guc_ct_send_recv: Inject an error when calling
> xe_guc_ct_send_recv
> > + */
> > +static void probe_fail_guc(int fd, char pci_slot[], const char
> function_name[],
> > + struct fault_injection_params *fault_params)
> > +{
> > + int iter_start = 0, iter_end = 0, iter = 0;
> > +
> > + igt_assert(fault_params);
> > +
> > + /* Get the iteration count from environment */
> > + iter = get_fault_inject_iter();
> > + iter_start = iter ? : 0;
>
> Can't it be just iter_start = iter; ?
>
> > + iter_end = iter ? iter + 1 : INJECT_ITERATIONS;
> > + for (int i = iter_start; i < iter_end; i++) {
> > + fault_params->space = i;
> > + setup_injection_fault(fault_params);
> > + inject_fault_probe(fd, pci_slot, function_name);
> > + igt_kmod_unbind("xe", pci_slot);
> > + }
> > +}
> > +
> > /**
> > * SUBTEST: exec-queue-create-fail-%s
> > * Description: inject an error in function %arg[1] used in exec queue create
> IOCTL to make it fail
> > @@ -406,6 +453,7 @@ igt_main
> > {
> > int fd, sysfs;
> > struct drm_xe_engine_class_instance *hwe;
> > + struct fault_injection_params fault_params;
> > static uint32_t devid;
> > char pci_slot[NAME_MAX];
> > const struct section {
> > @@ -463,6 +511,12 @@ igt_main
> > { }
> > };
> >
> > + const struct section guc_fail_functions[] = {
> > + { "xe_guc_mmio_send_recv" },
> > + { "xe_guc_ct_send_recv" },
> > + { }
> > + };
> > +
> > igt_fixture {
> > igt_require(fail_function_injection_enabled());
> > fd = drm_open_driver(DRIVER_XE);
> > @@ -505,6 +559,13 @@ igt_main
> > igt_subtest_f("inject-fault-probe-function-%s", s->name)
> > inject_fault_probe(fd, pci_slot, s->name);
> >
> > + for (const struct section *s = guc_fail_functions; s->name; s++)
> > + igt_subtest_f("probe-fail-guc-%s", s->name) {
> > + memcpy(&fault_params, &default_fault_params,
> > + sizeof(struct fault_injection_params));
> > + probe_fail_guc(fd, pci_slot, s->name, &fault_params);
> > + }
> > +
> > igt_fixture {
> > close(sysfs);
> > drm_close_driver(fd);
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