[PATCH v2 3/3] RFC drm/xe: add fault injection for lmem init check
Riana Tauro
riana.tauro at intel.com
Tue Mar 19 04:46:47 UTC 2024
Hi Rodrigo
On 3/19/2024 2:45 AM, Rodrigo Vivi wrote:
> On Fri, Mar 15, 2024 at 03:35:30PM +0530, Riana Tauro wrote:
>> add a boot time fault injection for lmem init check.
>> This can be triggered by adding a modparam fail_lmem_init
>>
>> xe.fail_lmem_init=<interval>,<probability>,<space>,<times>
>
> Please let's avoid module parameters as much as we can.
>
> Let's use the CONFIG_FAULT_INJECTION_DEBUG_FS
> similarly to
>
> fault_create_debugfs_attr("fail_gt_reset", root, >_reset_f\
> ailure);
>
lmem init check is done during early probe. We cannot set debugfs before
probe completes. So i added the module parameter.
I can try to set static values before injecting fault if module param is
not needed.
lmem_init_fail.times = 1;
lmem_init_fail.probability = 100;
Thanks
Riana
> And then use it like this:
>
> https://lore.kernel.org/all/20240315010843.194335-1-rodrigo.vivi@intel.com/
>
>>
>> Adding this causes the lmem init check to fail causing
>> the probe to defer.
>>
>> v2: add fault injection (Lucas)
>>
>> Signed-off-by: Riana Tauro <riana.tauro at intel.com>
>> ---
>> drivers/gpu/drm/xe/xe_device.c | 21 +++++++++++++++++++++
>> drivers/gpu/drm/xe/xe_module.c | 5 +++++
>> drivers/gpu/drm/xe/xe_module.h | 3 +++
>> 3 files changed, 29 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
>> index 50473329cce7..393610e95bd1 100644
>> --- a/drivers/gpu/drm/xe/xe_device.c
>> +++ b/drivers/gpu/drm/xe/xe_device.c
>> @@ -51,6 +51,10 @@ struct lockdep_map xe_device_mem_access_lockdep_map = {
>> };
>> #endif
>>
>> +#ifdef CONFIG_FAULT_INJECTION
>> +DECLARE_FAULT_ATTR(lmem_init_fail);
>> +#endif
>> +
>> static int xe_file_open(struct drm_device *dev, struct drm_file *file)
>> {
>> struct xe_device *xe = to_xe_device(dev);
>> @@ -431,6 +435,23 @@ static int wait_for_lmem_ready(struct xe_device *xe)
>> if (IS_SRIOV_VF(xe))
>> return 0;
>>
>> +#ifdef CONFIG_FAULT_INJECTION
>> + /*
>> + * use fault injection to cause a lmem init failure to validate
>> + * deferred probe. Set the verbose to 0 to avoid dump stack
>> + */
>> + if (xe_modparam.fail_lmem_init) {
>> + setup_fault_attr(&lmem_init_fail, xe_modparam.fail_lmem_init);
>> + lmem_init_fail.verbose = 0;
>> + if (should_fail(&lmem_init_fail, 1)) {
>> + /* add delay to reduce the number of deferred probe attempts */
>> + msleep(500);
>> + drm_dbg(&xe->drm, "Fault Injection lmem init failure\n");
>> + return -EPROBE_DEFER;
>> + }
>> + }
>> +#endif
>> +
>> if (verify_lmem_ready(gt))
>> return 0;
>>
>> diff --git a/drivers/gpu/drm/xe/xe_module.c b/drivers/gpu/drm/xe/xe_module.c
>> index 110b69864656..c4efbab430a7 100644
>> --- a/drivers/gpu/drm/xe/xe_module.c
>> +++ b/drivers/gpu/drm/xe/xe_module.c
>> @@ -48,6 +48,11 @@ module_param_named_unsafe(force_probe, xe_modparam.force_probe, charp, 0400);
>> MODULE_PARM_DESC(force_probe,
>> "Force probe options for specified devices. See CONFIG_DRM_XE_FORCE_PROBE for details.");
>>
>> +#ifdef CONFIG_FAULT_INJECTION
>> +module_param_named_unsafe(fail_lmem_init, xe_modparam.fail_lmem_init, charp, 0400);
>> +MODULE_PARM_DESC(fail_lmem_init, "Fault injection. fail_lmem_init=<interval>,<probability>,<space>,<times>");
>> +#endif
>> +
>> struct init_funcs {
>> int (*init)(void);
>> void (*exit)(void);
>> diff --git a/drivers/gpu/drm/xe/xe_module.h b/drivers/gpu/drm/xe/xe_module.h
>> index 88ef0e8b2bfd..ccbeacbc3efb 100644
>> --- a/drivers/gpu/drm/xe/xe_module.h
>> +++ b/drivers/gpu/drm/xe/xe_module.h
>> @@ -18,6 +18,9 @@ struct xe_modparam {
>> char *huc_firmware_path;
>> char *gsc_firmware_path;
>> char *force_probe;
>> +#if IS_ENABLED(CONFIG_FAULT_INJECTION)
>> + char *fail_lmem_init;
>> +#endif /* CONFIG_FAULT_INJECTION */
>> };
>>
>> extern struct xe_modparam xe_modparam;
>> --
>> 2.40.0
>>
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