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Subject: Re: [Regression] "iommu/amd: Relax locking in dma_ops path" makes tg3
 ethernet transmit queue timeout
From:   Kai-Heng Feng <kai.heng.feng@canonical.com>
In-Reply-To: <20200821134300.GM3354@suse.de>
Date:   Fri, 21 Aug 2020 21:50:33 +0800
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To:     Joerg Roedel <jroedel@suse.de>
Sender: linux-kernel-owner@vger.kernel.org
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Hi Joerg,

> On Aug 21, 2020, at 21:43, Joerg Roedel <jroedel@suse.de> wrote:
> 
> Hi Kai,
> 
> On Mon, Jun 29, 2020 at 08:33:22PM +0800, Kai-Heng Feng wrote:
>> I am still seeing the issue on v5.8-rc3. The issue goes away as soon
>> as "iommu=off" is added.
> 
> Can you probably help with debugging this issue? I've had no luck so far
> getting my hands on a machine with tg3 hardware and an AMD IOMMU.

Of course, I still have the system at my side.

The offending commit is 92d420ec028d ("iommu/amd: Relax locking in dma_ops path"), however be62dbf554c5 ("iommu/amd: Convert AMD iommu driver to the dma-iommu api") removed .map_page entirely so I don't know where to start.

Kai-Heng

> 
> Regards,
> 
> 	Joerg