Re: [Qemu-devel] [PATCH v2 0/5] fw_cfg_test refactor and add two test cases

[Li Qiang]

Li Qiang <address@hidden> 于2019年4月25日周四 下午10:29写道：

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> Thomas Huth <address@hidden> 于2019年4月25日周四 下午5:57写道：
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>> On 24/04/2019 16.06, Li Qiang wrote:
>> > In the disscuss of adding reboot timeout test case:
>> > https://lists.gnu.org/archive/html/qemu-devel/2019-04/msg03304.html
>> >
>> > Philippe suggested we should uses the only related option for one
>> > specific test. However currently we uses one QTestState for all the
>> > test cases. In order to achieve Philippe's idea, I split the test case
>> > for its own QTestState. As this patchset has changed a lot, I don't bump
>> > the version.
>> >
>> > Change since v1:
>> > Add a patch to store the reboot_timeout as little endian
>> > Fix the endian issue per Thomas's review
>>
>> The test still aborts on a big endian host:
>>
>> $ QTEST_QEMU_BINARY=x86_64-softmmu/qemu-system-x86_64 tests/fw_cfg-test
>> /x86_64/fw_cfg/signature: OK
>> /x86_64/fw_cfg/id: OK
>> /x86_64/fw_cfg/uuid: OK
>> /x86_64/fw_cfg/ram_size: OK
>> /x86_64/fw_cfg/nographic: OK
>> /x86_64/fw_cfg/nb_cpus: OK
>> /x86_64/fw_cfg/max_cpus: OK
>> /x86_64/fw_cfg/numa: OK
>> /x86_64/fw_cfg/boot_menu: OK
>> /x86_64/fw_cfg/reboot_timeout: **
>>
>> ERROR:/home/thuth/devel/qemu/tests/fw_cfg-test.c:190:test_fw_cfg_reboot_timeout:
>> assertion failed (reboot_timeout == 15): (251658240 == 15)
>> Aborted
>>
>> 251658240 is 0x0F000000, i.e. a byte-swapped 0xf = 15 ... i.e. you still
>> got an endianess issue somewhere in the code.
>>
>
>
> Hmmmm,
>
> I have thought a long time, still can't point where is wrong.
>
> Let's from the result:
> 0x0f000000 in the big endian laid as this:
> low ---> high
> 0x0f 00 00 00
>
> As I have swapped before the compare so it is read as this:
> low ---> high
> 00 00 00 0x0f
>
> However from the store side:
> the 15 in big endian is:
> low ---> high
> 00 00 00 0x0f
>
> But Before I store it, I convert it to little endian, so following should
> be stored:
> low ---> high
> 0x0f 00 00 00
>
> Do you apply the patch 3 and recompile the qemu binary?
>


Hello Thomas,
I have tested again this and just store it as big endian(so that the
store/load has different endianness),
I don't see any error.

Also, can we add these test sceneries(big-endian host) in our CI? so that
the bot can report for every commit.


Thanks,
Li Qiang



If it is, I may need your help as I have no big endian host device.
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> You can debug and  inspect the memory layout and point out where is wrong.
>
> Thanks,
> Li Qiang
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>>
>>  Thomas
>>
>