[PATCH v7 00/12] Fix kdump faults on system with amd iommu

From: Baoquan He
Date: Fri Nov 25 2016 - 00:14:42 EST

This is v7 post.

The principle of the fix is similar to intel iommu. Just defer the assignment
of device to domain to device driver init. In this version of post, a new
call-back is_attach_deferred is added to iommu-ops, it's used to check whether
we need defer the domain attach/detach in iommu-core code.

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.

According to Joerg's comments made several below main changes:
- Add sanity check when copy old dev tables.

- 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).

Two main changes are made according to Joerg's suggestion:
- Add is_attach_deferred call-back to iommu-ops. With this domain
can be deferred to device driver init cleanly.

- Allocate memory below 4G for dev table if translation pre-enabled.
AMD engineer pointed out that it's unsafe to update the device-table
while iommu is enabled. device-table pointer update is split up into
two 32bit writes in the IOMMU hardware. So updating it while the IOMMU
is enabled could have some nasty side effects.

Baoquan He (12):
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: Add is_attach_deferred call-back to iommu-ops
iommu/amd: Use is_attach_deferred call-back
iommu/amd: Add sanity check of irq remap information of old dev table
iommu/amd: Don't copy GCR3 table root pointer
iommu/amd: Clear out the GV flag when handle deferred domain attach
iommu: Assign the direct mapped domain to group->domain
iommu/amd: Allocate memory below 4G for dev table if translation

drivers/iommu/amd_iommu.c | 78 +++++++++-------
drivers/iommu/amd_iommu_init.c | 201 +++++++++++++++++++++++++++++++++++++---
drivers/iommu/amd_iommu_proto.h | 2 +
drivers/iommu/amd_iommu_types.h | 53 ++++++++++-
drivers/iommu/amd_iommu_v2.c | 18 +++-
drivers/iommu/iommu.c | 9 ++
include/linux/iommu.h | 1 +
7 files changed, 313 insertions(+), 49 deletions(-)