[PATCH v4 05/16] iommu: Move bus setup to IOMMU device registration
Baolu Lu
baolu.lu at linux.intel.com
Wed Oct 12 18:08:05 PDT 2022
Hi Alex,
On 2022/10/13 0:28, Alex Williamson wrote:
> On Mon, 15 Aug 2022 17:20:06 +0100
> Robin Murphy<robin.murphy at arm.com> wrote:
>
>> Move the bus setup to iommu_device_register(). This should allow
>> bus_iommu_probe() to be correctly replayed for multiple IOMMU instances,
>> and leaves bus_set_iommu() as a glorified no-op to be cleaned up next.
>>
>> At this point we can also handle cleanup better than just rolling back
>> the most-recently-touched bus upon failure - which may release devices
>> owned by other already-registered instances, and still leave devices on
>> other buses with dangling pointers to the failed instance. Now it's easy
>> to clean up the exact footprint of a given instance, no more, no less.
>>
>> Tested-by: Marek Szyprowski<m.szyprowski at samsung.com>
>> Reviewed-By: Krishna Reddy<vdumpa at nvidia.com>
>> Reviewed-by: Kevin Tian<kevin.tian at intel.com>
>> Tested-by: Matthew Rosato<mjrosato at linux.ibm.com> # s390
>> Tested-by: Niklas Schnelle<schnelle at linux.ibm.com> # s390
>> Signed-off-by: Robin Murphy<robin.murphy at arm.com>
>> ---
>>
>> v4: Factor out the ops check in iommu_device_register() to keep the loop
>> even simpler, and comment the nominal change in behaviour
>>
>> drivers/iommu/iommu.c | 55 +++++++++++++++++++++++--------------------
>> 1 file changed, 30 insertions(+), 25 deletions(-)
> This introduces the below lockdep spat regression, bisected to commit:
>
> 57365a04c921 ("iommu: Move bus setup to IOMMU device registration")
>
> This can be reproduced with simple vfio-pci device assignment to a VM
> on x86_64 with VT-d. Thanks,
Thank you for reporting this. I have proposed below fix:
https://lore.kernel.org/all/20220927053109.4053662-1-baolu.lu@linux.intel.com/
Does it work for you?
Best regards,
baolu
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