[0/2] iommu: Fix the longstanding probe issues

Message

Robin Murphy Feb. 13, 2025, 11:48 p.m. UTC

Hi all,

Finally, it's that thing I've been mentioning on and off for the last 5
years or so! After far too much thinking about "clean" ways to refactor
everything towards an eventual goal of working properly, I finally gave
up and decided to see how bad it would be to just get it working, then
worry about cleaning up afterwards. Frankly I still can't quiet believe
how small the patch turned out to be...

Patch #1 is a fix for what I think is the only "expected" race in the
core API design - we knew we had that window where a default domain is
NULL, but the potential consequences weren't clear until Charan figured
it out the hard way. That should be good to go already, and it's not
strictly a dependency for patch #2, but it seemed worth posting them
together on the common theme.

Patch #2 is then the first big bite out of the problem I feel compelled
to fix because it's my name on d7b0558230e4 ("iommu/of: Prepare for
deferred IOMMU configuration") which, in hindsight, started it. I hope
this will be the only patch which has to touch absolutely everything all
at once. I've not got very far with the follow-up patches yet, but I do
foresee being able to tackle the driver core, firmware subsystems and
bus drivers more independently. I don't expect anyone to love it, but I
hope you can at least see where I'm going and give a bit of leeway for
now :)

I also do rather expect that WARN_ON to be hit, but the intent is that
I'd like to get the attention of any of_dma_configure() abusers so they
can help me figure out what the heck their code *should* be doing...

Thanks,
Robin.


Robin Murphy (2):
  iommu: Handle race with default domain setup
  iommu: Get DT/ACPI parsing into the proper probe path

 drivers/acpi/arm64/dma.c        |  5 ++++
 drivers/acpi/scan.c             | 10 +++----
 drivers/amba/bus.c              |  2 +-
 drivers/base/platform.c         |  2 +-
 drivers/bus/fsl-mc/fsl-mc-bus.c |  2 +-
 drivers/cdx/cdx.c               |  2 +-
 drivers/iommu/iommu.c           | 48 +++++++++++++++++++++++++--------
 drivers/iommu/of_iommu.c        | 10 ++++++-
 drivers/of/device.c             |  7 ++++-
 drivers/pci/pci-driver.c        |  2 +-
 10 files changed, 65 insertions(+), 25 deletions(-)