From: Gary R Hook <ghook@amd.com>
To: Eric Pilmore <epilmore@gigaio.com>, "Mehta, Sanju" <Sanju.Mehta@amd.com>
Cc: S Taylor <staylor@gigaio.com>, D Meyer <dmeyer@gigaio.com>,
linux-ntb <linux-ntb@googlegroups.com>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
Subject: Re: Fwd: AMD IO_PAGE_FAULT w/NTB on Write ops?
Date: Thu, 9 May 2019 20:03:17 +0000 [thread overview]
Message-ID: <8e4ccf44-9e4f-8007-ddcc-431440f9d533@amd.com> (raw)
In-Reply-To: <CAOQPn8sQ+B97UptHpxJgdmcMxBZrqGynQR8qTc3q77fAODRH-A@mail.gmail.com>
On 4/24/19 5:04 PM, Eric Pilmore wrote:
> On Tue, Apr 23, 2019 at 4:00 AM Sanjay R Mehta <sanmehta@amd.com> wrote:
>>
>>
>>> AMD-Vi: Event logged [IO_PAGE_FAULT device=23:01.2 domain=0x0000
>>> address=0x00000000fde1c18c flags=0x0070]
>>
>> the address in the above log looks to be physical address of memory window. Am I Right?
>>
>> If yes then, the first parameter of dma_alloc_coherent() to be passed as below,
>>
>> dma_alloc_coherent(&ntb->pdev->dev, ...)instead of dma_alloc_coherent(&ntb->dev, ...).
>>
>> Hope this should solve your problem.
>
> Hi Sanjay,
>
> Thanks the for the response. We are using the correct device for the
> dma_alloc_coherent(). Upon further investigation what we are finding
> is that apparently the AMD IOMMU support can only manage one alias, as
> opposed to Intel IOMMU support which can support multiple. Not clear
> at this time if it's a software limitation in the AMD IOMMU kernel
> support or an imposed limitation of the hardware. Still investigating.
Please define 'alias'?
The IO_PAGE_FAULT error is described on page 142 of the AMD IOMMU spec,
document #48882. Easily found via a search.
The flags value of 0x0070 translates to PE, RW, PR. The page was
present, the transaction was a write, and the peripheral didn't have
permission. That implies that mapping hadn't been done.
Not being sure how that device presents, or what you're doing with IVHD
info, I can't comment further. I can say that the AMD IOMMU provides for
a single exclusion range, but as many unity ranges as you wish.
HTH
grh
next prev parent reply other threads:[~2019-05-09 20:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-20 9:06 AMD IO_PAGE_FAULT w/NTB on Write ops? Eric Pilmore
2019-04-22 17:14 ` Logan Gunthorpe
2019-04-22 17:31 ` Logan Gunthorpe
2019-09-06 23:48 ` AMD Epyc iperf perfomance issues over NTB Kit Chow
[not found] ` <CAADLhr49ke_3s25gW11qZ+H-Jjje-E00WMHiMDbKU=mcCQtb3g@mail.gmail.com>
2019-04-23 11:00 ` Fwd: AMD IO_PAGE_FAULT w/NTB on Write ops? Sanjay R Mehta
2019-04-24 22:04 ` Eric Pilmore
2019-05-09 20:03 ` Gary R Hook [this message]
2019-06-04 21:15 ` Eric Pilmore
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