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SubjectRe: [PATCH v6 0/9] Fix kdump faults on system with amd iommu
On 11/04/16 at 01:14pm, Baoquan He wrote:
> Hi Joerg,
>
> Ping!
>
> About the v6 post, do you have any suggestions?
>
> Because of GCR3 special handling in patch 9/9, I spent several days to
> study the knowledge and change code. Then when I tried to post, the
> virtual interrupt remapping feature caused kernel hang with this pachset
> applied. So it took me days to study spec and find it out. Finally it's
> very late to post.
>
> Coule it be possibe that we review and merge patch 9/1~8, and leave the
> patch 9/9 which includes GCR3 special handling as 2nd step issue? Then
> I can back port patch 9/1~8 to our distro. Since this bug has been
> discussed so long time, and currently almost all system are deployed
> with amd iommu v1 hardware. It would be great if they can be accepted
~~~~~~~~~~~~~~~~~~~~~~~~~~~ Here I meant in our Redhat lab almost all
system are only deployed with amd iommu v1 support.

> into 4.9 or 4.10-rc phase.
>
> About patch 9/9, its code is a little complicated and not being
> reviewed, I am not sure if I understand your suggestion and GCR3 code
> well. What's your opinion?
>
> Thanks
> Baoquan
>
>
> On 10/20/16 at 07:37pm, Baoquan He wrote:
> > This is v6 post.
> >
> > The principle of the fix is similar to intel iommu. Just defer the assignment
> > of device to domain to device driver init. But there's difference than
> > intel iommu. AMD iommu create protection domain and assign device to
> > domain in iommu driver init stage. So in this patchset I just allow the
> > assignment of device to domain in software level, but defer updating the
> > domain info, especially the pte_root to dev table entry to device driver
> > init stage.
> >
> > v5:
> > bnx2 NIC can't reset itself during driver init. Post patch to reset
> > it during driver init. IO_PAGE_FAULT can't be seen anymore.
> >
> > Below is link of v5 post.
> > https://lists.linuxfoundation.org/pipermail/iommu/2016-September/018527.html
> >
> > v5->v6:
> > According to Joerg's comments made several below main changes:
> > - Add sanity check when copy old dev tables.
> >
> > - Discard the old patch 6/8.
> >
> > - If a device is set up with guest translations (DTE.GV=1), then don't
> > copy that information but move the device over to an empty guest-cr3
> > table and handle the faults in the PPR log (which just answer them
> > with INVALID).
> >
> > Issues need be discussed:
> > - Joerg suggested hooking the behaviour that updates domain info into
> > dte entry into the set_dma_mask call-back. I tried, but on my local
> > machine with amd iommu v2, an ohci pci device doesn't call set_dma_mask.
> > Then IO_PAGE_FAULT printing flooded.
> >
> > 00:12.0 USB controller: Advanced Micro Devices, Inc. [AMD] FCH USB OHCI Controller (rev 11)
> >
> > - About GCR3 root pointer copying issue, I don't know how to setup the
> > test environment and haven't tested yet. Hope Joerg or Zongshun can
> > tell what steps should be taken to test it, or help take a test in your
> > test environemnt.
> >
> > Baoquan He (9):
> > iommu/amd: Detect pre enabled translation
> > iommu/amd: add several helper function
> > iommu/amd: Define bit fields for DTE particularly
> > iommu/amd: Add function copy_dev_tables
> > iommu/amd: copy old trans table from old kernel
> > iommu/amd: Don't update domain info to dte entry at iommu init stage
> > iommu/amd: Update domain into to dte entry during device driver init
> > iommu/amd: Add sanity check of irq remap information of old dev table
> > entry
> > iommu/amd: Don't copy GCR3 table root pointer
> >
> > drivers/iommu/amd_iommu.c | 93 +++++++++++++-------
> > drivers/iommu/amd_iommu_init.c | 189 +++++++++++++++++++++++++++++++++++++---
> > drivers/iommu/amd_iommu_proto.h | 2 +
> > drivers/iommu/amd_iommu_types.h | 53 ++++++++++-
> > drivers/iommu/amd_iommu_v2.c | 18 +++-
> > 5 files changed, 307 insertions(+), 48 deletions(-)
> >
> > --
> > 2.5.5
> >

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