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Subject: Re: [PATCH v12 4/4] Documentation: add debugfs description for vfio
To:     Jason Gunthorpe <jgg@nvidia.com>
CC:     <alex.williamson@redhat.com>,
        <shameerali.kolothum.thodi@huawei.com>,
        <jonathan.cameron@huawei.com>, <cohuck@redhat.com>,
        <linux-kernel@vger.kernel.org>, <linuxarm@openeuler.org>
References: <20230728072104.64834-1-liulongfang@huawei.com>
 <20230728072104.64834-5-liulongfang@huawei.com> <ZM0SAfIHnMHndm8h@nvidia.com>
From:   liulongfang <liulongfang@huawei.com>
Message-ID: <3c557239-447f-116d-3687-cc6e419f2dcc@huawei.com>
Date:   Mon, 7 Aug 2023 09:33:07 +0800
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On 2023/8/4 22:58, Jason Gunthorpe wrote:
> On Fri, Jul 28, 2023 at 03:21:04PM +0800, liulongfang wrote:
>> From: Longfang Liu <liulongfang@huawei.com>
>>
>> 1.Add two debugfs document description file to help users understand
>> how to use the accelerator live migration driver's debugfs.
>> 2.Update the file paths that need to be maintained in MAINTAINERS
>>
>> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
>> ---
>>  .../ABI/testing/debugfs-hisi-migration        | 36 +++++++++++++++++++
>>  Documentation/ABI/testing/debugfs-vfio        | 25 +++++++++++++
>>  MAINTAINERS                                   |  2 ++
>>  3 files changed, 63 insertions(+)
>>  create mode 100644 Documentation/ABI/testing/debugfs-hisi-migration
>>  create mode 100644 Documentation/ABI/testing/debugfs-vfio
>>
>> diff --git a/Documentation/ABI/testing/debugfs-hisi-migration b/Documentation/ABI/testing/debugfs-hisi-migration
>> new file mode 100644
>> index 000000000000..791dd8a09575
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/debugfs-hisi-migration
>> @@ -0,0 +1,36 @@
>> +What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/data
>> +Date:		Aug 2023
>> +KernelVersion:  6.6
>> +Contact:	Longfang Liu <liulongfang@huawei.com>
>> +Description:	Read the live migration data of the vfio device.
>> +		These data include device status data, queue configuration
>> +		data and some task configuration data.
>> +		The output format of the data is defined by the live
>> +		migration driver.
>> +
>> +What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/attr
>> +Date:		Aug 2023
>> +KernelVersion:  6.6
>> +Contact:	Longfang Liu <liulongfang@huawei.com>
>> +Description:	Read the live migration attributes of the vfio device.
>> +		it include device status attributes and data length attributes
>> +		The output format of the attributes is defined by the live
>> +		migration driver.
>> +
>> +What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/io_test
>> +Date:		Aug 2023
>> +KernelVersion:  6.6
>> +Contact:	Longfang Liu <liulongfang@huawei.com>
>> +Description:	Trigger the HiSilicon accelerator device to perform
>> +		the io test through the read operation. If successful,
>> +		it returns the execution result of mailbox. If fails,
>> +		it returns error log result.
>> +
>> +What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/save
>> +Date:		Aug 2023
>> +KernelVersion:  6.6
>> +Contact:	Longfang Liu <liulongfang@huawei.com>
>> +Description:	Trigger the Hisilicon accelerator device to perform
>> +		the state saving operation of live migration through the read
>> +		operation, and output the operation log results.
> 
> I still very much do not like this use of debugfs.
> 
> If you want to test migration then make a test program and use the
> normal api
>
These debugfs are just to get internal state data.
The test function is no longer executed.
The store file with test function has been deleted.

Thanks,
Longfang.

> Creating some parallel backdoor to work the same API is just
> unneeded complexity.
> 
> Jason
> .
>