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From: Eric Pilmore <epilmore@gigaio.com>
To: linux-pci@vger.kernel.org
Subject: IOAT DMA w/IOMMU
Date: Thu, 9 Aug 2018 11:14:13 -0700	[thread overview]
Message-ID: <CAOQPn8soxubJxb=vp7kz+AM6LbPH5y+_Nx0Vzv7rjV_nMMqEmA@mail.gmail.com> (raw)

Didn't get any response on the IRC channel so trying here.

Was wondering if anybody here has used IOAT DMA engines with an
IOMMU turned on (Xeon based system)? My specific question is really
whether it is possible to DMA (w/IOAT) to a PCI BAR address as the
destination without having to map that address to the IOVA space of the
DMA engine first (assuming the IOMMU is on)?

I am encountering issues where I see PTE Errors reported from DMAR in this
scenario, but I do not if I use a different DMA engine that's sitting downstream
off the PCI tree. I'm wondering if the IOAT DMA failure is some
artifact of these
engines sitting behind the Host Bridge.

Thanks in advance!
Eric

             reply	other threads:[~2018-08-09 20:40 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-09 18:14 Eric Pilmore [this message]
2018-08-09 18:43 ` IOAT DMA w/IOMMU Bjorn Helgaas
2018-08-09 18:51   ` Eric Pilmore
2018-08-09 19:35     ` Logan Gunthorpe
2018-08-09 19:47       ` Kit Chow
2018-08-09 20:11         ` Logan Gunthorpe
2018-08-09 20:57           ` Kit Chow
2018-08-09 21:11             ` Logan Gunthorpe
2018-08-09 21:47               ` Kit Chow
2018-08-09 22:40                 ` Jiang, Dave
2018-08-09 22:48                   ` Kit Chow
2018-08-09 22:50                     ` Logan Gunthorpe
2018-08-09 23:00                       ` Kit Chow
2018-08-10 16:02                         ` Kit Chow
2018-08-10 16:23                           ` Kit Chow
2018-08-10 16:24                             ` Logan Gunthorpe
2018-08-10 16:24                           ` Logan Gunthorpe
2018-08-10 16:31                             ` Dave Jiang
2018-08-10 16:33                               ` Logan Gunthorpe
2018-08-10 17:01                                 ` Dave Jiang
2018-08-10 17:15                                   ` Logan Gunthorpe
2018-08-10 17:46                                     ` Dave Jiang
2018-08-11  0:53                                       ` Kit Chow
2018-08-11  2:10                                         ` Logan Gunthorpe
2018-08-13 14:23                                           ` Kit Chow
2018-08-13 14:59                                             ` Robin Murphy
2018-08-13 15:21                                               ` Kit Chow
2018-08-13 23:30                                                 ` Kit Chow
2018-08-13 23:39                                                   ` Logan Gunthorpe
2018-08-13 23:48                                                     ` Kit Chow
2018-08-13 23:50                                                       ` Logan Gunthorpe
2018-08-14 13:47                                                         ` Kit Chow
2018-08-14 14:03                                                         ` Robin Murphy
2018-08-13 23:36                                                 ` Kit Chow
2018-08-09 21:31       ` Eric Pilmore
2018-08-09 21:36         ` Logan Gunthorpe
2018-08-16 17:16           ` Kit Chow
2018-08-16 17:21             ` Logan Gunthorpe
2018-08-16 18:53               ` Kit Chow
2018-08-16 18:56                 ` Logan Gunthorpe
2018-08-21 23:18                   ` Eric Pilmore
2018-08-21 23:20                     ` Logan Gunthorpe
2018-08-21 23:28                       ` Eric Pilmore
2018-08-21 23:35                         ` Logan Gunthorpe
2018-08-21 23:45                           ` Eric Pilmore
2018-08-21 23:53                             ` Logan Gunthorpe
2018-08-21 23:59                               ` Eric Pilmore
2018-08-21 23:30                       ` Eric Pilmore

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