Re: [PATCH] selftests: iommu: add config needed for iommufd_fail_nth

[Joao Martins <joao.m.martins@oracle.com>]

On 27/03/2024 17:49, Muhammad Usama Anjum wrote:
> On 3/27/24 7:59 PM, Joao Martins wrote:
>> On 27/03/2024 11:49, Jason Gunthorpe wrote:
>>> On Wed, Mar 27, 2024 at 03:14:25PM +0500, Muhammad Usama Anjum wrote:
>>>> On 3/26/24 8:03 PM, Jason Gunthorpe wrote:
>>>>> On Tue, Mar 26, 2024 at 06:09:34PM +0500, Muhammad Usama Anjum wrote:
>>>>>> Even after applying this config patch and following snippet (which doesn't
>>>>>> terminate the program if mmap doesn't allocate exactly as the hint), I'm
>>>>>> finding failed tests.
>>>>>>
>>>>>> @@ -1746,7 +1748,7 @@ FIXTURE_SETUP(iommufd_dirty_tracking)
>>>>>>         assert((uintptr_t)self->buffer % HUGEPAGE_SIZE == 0);
>>>>>>         vrc = mmap(self->buffer, variant->buffer_size, PROT_READ | PROT_WRITE,
>>>>>>                    mmap_flags, -1, 0);
>>>>>> -       assert(vrc == self->buffer);
>>>>>> +       assert(vrc == self->buffer);// ???
>>>>>>
>>>>>> On x86:
>>>>>> # Totals: pass:176 fail:4 xfail:0 xpass:0 skip:0 error:0
>>>>>> On ARM64:
>>>>>> # Totals: pass:166 fail:14 xfail:0 xpass:0 skip:0 error:0
>>>>>>
>>>>>> The log files are attached.
>>>>>
>>>>> You probably don't have enough transparent huge pages available to the process
>>>>>
>>>>>       echo 1024 > /proc/sys/vm/nr_hugepages
>>>> After making huge pages available, the iommufd test always passed on x86.
>>>> But there are still failures on arm64. I'm looking into the failures.
>>>
>>> Oh that is really strange. Joao? Nicolin?
>>>
>> Definitely strange, I'll have a look.
>>
>> So it set the expected number of dirty bits as that assert doesn't fail, but it
>> is failing when we check that even bits are set but not odd ones. Like it's
>> hasn't set those bits.
>>
>> For mock tests there should be no difference between x86 and ARM assuming the
>> typical 4K page-size. Maybe this is 64k base pages in ARM? That's the only thing
>> that I can think of that affected mock domain.
> The config is attached. The defaults are being used i.e., 4k page.

Looks like CONFIG_IOMMUFD_DRIVER is not defined :(

Thus no bits are being set.