Re: [Regression] "iommu/amd: Relax locking in dma_ops path" makes tg3 ethernet transmit queue timeout

From: Kai-Heng Feng
Date: Mon Jun 29 2020 - 18:39:46 EST



> On May 18, 2020, at 23:32, Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> wrote:
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>> On May 18, 2020, at 22:05, Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> wrote:
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>>> On May 18, 2020, at 21:32, Joerg Roedel <jroedel@xxxxxxx> wrote:
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>>> On Mon, May 18, 2020 at 05:06:45PM +0800, Kai-Heng Feng wrote:
>>>> Particularly, as soon as the spinlock is removed, the issue can be reproduced.
>>>> Function domain_flush_complete() doesn't seem to affect the status.
>>>>
>>>> However, the .map_page callback was removed by be62dbf554c5
>>>> ("iommu/amd: Convert AMD iommu driver to the dma-iommu api"), so
>>>> there's no easy revert for this issue.
>>>>
>>>> This is still reproducible as of today's mainline kernel, v5.7-rc6.
>>>
>>> Is there any error message from the IOMMU driver?
>>>
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>> As of mainline kernel, there's no error message from IOMMU driver.
>> There are some complains from v4.15-rc1:
>> https://pastebin.ubuntu.com/p/qn4TXkFxsc/
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> Just tested v5.7-rc6, the issue disappears as soon as kernel boots with "iommu=off".

I am still seeing the issue on v5.8-rc3. The issue goes away as soon as "iommu=off" is added.

Kai-Heng

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> Kai-Heng
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>> Kai-Heng
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