Re: [igt-dev] [PATCH i-g-t] lib/xe/xe_query: Extern xe_supports_faults()

[Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>]

On Fri, Mar 24, 2023 at 07:12:46AM +0100, Mauro Carvalho Chehab wrote:
>On Thu, 23 Mar 2023 22:02:53 -0700
>Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com> wrote:
>
>> Do not check for supports_faults in xe_device_get() as
>> it creates a VM in fault mode which prohibits creation
>> of any other VM in non-fault mode until this fault mode
>> VM is closed. This leads to test failures in multi threaded
>> cases.
>
>Hmm...
>
>>
>> Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
>> ---
>>  lib/xe/xe_query.c | 51 ++++++++++++++++++++++-------------------------
>>  lib/xe/xe_query.h |  3 ---
>>  2 files changed, 24 insertions(+), 30 deletions(-)
>>
>> diff --git a/lib/xe/xe_query.c b/lib/xe/xe_query.c
>> index 183523280..dc91d59bc 100644
>> --- a/lib/xe/xe_query.c
>> +++ b/lib/xe/xe_query.c
>> @@ -160,23 +160,6 @@ static uint32_t __mem_default_alignment(struct drm_xe_query_mem_usage *mem_usage
>>  	return alignment;
>>  }
>>
>> -static bool xe_check_supports_faults(int fd)
>> -{
>> -	bool supports_faults;
>> -
>> -	struct drm_xe_vm_create create = {
>> -		.flags = DRM_XE_VM_CREATE_ASYNC_BIND_OPS |
>> -			 DRM_XE_VM_CREATE_FAULT_MODE,
>> -	};
>> -
>> -	supports_faults = !igt_ioctl(fd, DRM_IOCTL_XE_VM_CREATE, &create);
>> -
>> -	if (supports_faults)
>> -		xe_vm_destroy(fd, create.vm_id);
>
>Weren't the VM supposed to be closed here?
>

Yes, but before it does destroy the VM, some other thread can try
to create a VM in non-fault mode and fail because we have created
a fault mode VM here. This happens in multi-threaded test like
xe_exec_threads.

Niranjana


>
>Regards,
>Mauro