Re: [Xen-devel] [PATCH] xen/arm: vgic-v3: Fix the typo of GICD IRQ active status range

[Wei Xu <xuwei5@hisilicon.com>]

Hi Julien,

On 2020/1/7 18:51, Julien Grall wrote:
>
>
> On 07/01/2020 09:28, Wei Xu wrote:
>> Hi Julien,
>>
>> On 2020/1/7 17:10, Julien Grall wrote:
>>>
>>>
>>> On 07/01/2020 08:39, Wei Xu wrote:
>>>> Hi Stefano,
>>>>
>>>> On 2020/1/7 6:01, Stefano Stabellini wrote:
>>>>> On Sat, 28 Dec 2019, Wei Xu wrote:
>>>>>> Hi Julien,
>>>>>>
>>>>>> On 2019/12/28 16:09, Julien Grall wrote:
>>>>>>> Hi,
>>>>>>>
>>>>>>> On 28/12/2019 03:08, Wei Xu wrote:
>>>>>>>> This patch fixes the typo about the active status range of an IRQ
>>>>>>>> via GICD. Otherwise it will be failed to handle the mmio access 
>>>>>>>> and
>>>>>>>> inject a data abort.
>>>>>>> I have seen a patch similar from NXP a month ago and I disagreed 
>>>>>>> on the
>>>>>>> approach.
>>>>>>>
>>>>>>> If you look at the context you modifed, it says that reading 
>>>>>>> ACTIVER is not
>>>>>>> supported. While I agree the behavior is not consistent accross 
>>>>>>> ACTIVER,
>>>>>>> injecting a data abort is a perfectly fine behavior to me 
>>>>>>> (though not spec
>>>>>>> compliant) as we don't implement the registers correctly.
>>>>>>>
>>>>>>> I guess you are sending this patch, because you tried Linux 5.4 
>>>>>>> (or later)
>>>>>>> on Xen, right? Linux has recently began to read ACTIVER to check 
>>>>>>> whether an
>>>>>>> IRQ is active at the HW level during the synchronizing of the 
>>>>>>> IRQS. From my
>>>>>>> understanding, this is used because there is a window where the 
>>>>>>> interrupt is
>>>>>>> active at the HW level but the Linux IRQ subsystem is not aware 
>>>>>>> of it.
>>>>>>>
>>>>>>> While the patch below will allow Linux 5.4 to not crash, it is 
>>>>>>> not going to
>>>>>>> make it fly very far because of the above. So I am rather not 
>>>>>>> happy with
>>>>>>> persuing with returning 0.
>>>>>>>
>>>>>> Yes, I am using Linux 5.5-rc2 :)
>>>>>> Got it and thanks for the explanation.
>>>>>> I am not insistent on this and OK to wait for the update.
>>>>>> Thanks and have a very happy new year!
>>>>> Hi Wei,
>>>>>
>>>>> what do you do to reproduce the issue? Are you just booting Linux
>>>>> 5.5-rc2 as dom0 and seeing the issue during boot, or are you doing
>>>>> something specific?
>>>>>
>>>>> .
>>>>>
>>>>
>>>> I directly tested the mainline kernel with defconfig.
>>>> And the 5.5-rc5 kernel booting log is as below:
>>>>
>>>>      root@ubuntu:~# dmesg | more
>>>>      [    0.000000] Booting Linux on physical CPU 0x0000000000 
>>>> [0x481fd010]
>>>>      [    0.000000] Linux version 5.5.0-rc5 (joyx@Turing-Arch-b) 
>>>> (gcc version 4.9.1 2
>>>>      0140505 (prerelease) (crosstool-NG linaro-1.13.1-4.9-2014.05 - 
>>>> Linaro GCC 4.9-20
>>>>      14.05)) #132 SMP PREEMPT Tue Jan 7 15:43:06 CST 2020
>>>>      [    0.000000] Xen XEN_VERSION.XEN_SUBVERSION support found
>>>>      [    0.000000] efi: Getting EFI parameters from FDT:
>>>>      [    0.000000] efi: EFI v2.50 by Xen
>>>>      [    0.000000] efi:  ACPI 2.0=0x181d0e70
>>>>      [    0.000000] cma: Reserved 32 MiB at 0x000000007e000000
>>>>      [    0.000000] ACPI: Early table checksum verification disabled
>>>>      [    0.000000] ACPI: RSDP 0x00000000181D0E70 000024 (v02 HISI  )
>>>>      [    0.000000] ACPI: XSDT 0x00000000181D0DB0 0000BC (v01 HISI 
>>>> HIP08    0000000
>>>>      0      01000013)
>>>
>>> Is that the full log from Linux? If not, can you post it in full?
>>
>> I will reply the other questions in another mail since the below log 
>> is too big.
>
> Maybe I am missing something, but Linux seems to be running fine and I 
> can't spot any error related to read the active status register. By 
> any chance, did you build Xen with your patch?
>

Yes, I built Xen with my patch.

Best Regards,
Wei

> Cheers,
>



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