linux-kernel - Re: [PATCH] selftests: iommu: add config needed for iommufd_fail

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Date: Thu, 4 Apr 2024 16:48:43 +0500
From: Muhammad Usama Anjum <usama.anjum@...labora.com>
To: Jason Gunthorpe <jgg@...pe.ca>, Joao Martins <joao.m.martins@...cle.com>
Cc: Muhammad Usama Anjum <usama.anjum@...labora.com>,
 Nicolin Chen <nicolinc@...dia.com>, kernel@...labora.com,
 iommu@...ts.linux.dev, linux-kselftest@...r.kernel.org,
 linux-kernel@...r.kernel.org, Kevin Tian <kevin.tian@...el.com>,
 Shuah Khan <shuah@...nel.org>
Subject: Re: [PATCH] selftests: iommu: add config needed for iommufd_fail_nth

On 3/28/24 1:13 AM, Muhammad Usama Anjum wrote:
> On 3/27/24 11:20 PM, Jason Gunthorpe wrote:
>> On Wed, Mar 27, 2024 at 06:09:37PM +0000, Joao Martins wrote:
>>> 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.
>>
>> Oh! 
>>
>> --- a/drivers/iommu/iommufd/Kconfig
>> +++ b/drivers/iommu/iommufd/Kconfig
>> @@ -37,6 +37,7 @@ config IOMMUFD_TEST
>>         depends on DEBUG_KERNEL
>>         depends on FAULT_INJECTION
>>         depends on RUNTIME_TESTING_MENU
>> +       select IOMMUFD_DRIVER
>>         default n
>>         help
>>           This is dangerous, do not enable unless running
>>
> Tested this patch on my system and it fixes all issues for ARM64. Please
> add tag for this Kconfig patch:
> Tested by: Muhammad Usama Anjum <usama.anjum@...labora.com>
> 
> Also please accept the patch in this current series.
Please let me know if you need me to send the config patch. Please accept
the config patch as well.

>>
>> ???
>>
>> Jason
> 

-- 
BR,
Muhammad Usama Anjum