[PATCH 02/13] iommu: Move bus setup to IOMMU device registration
Lu Baolu
baolu.lu at linux.intel.com
Tue Apr 19 03:13:57 PDT 2022
On 2022/4/19 15:20, Robin Murphy wrote:
> On 2022-04-19 00:37, Lu Baolu wrote:
>> On 2022/4/19 6:09, Robin Murphy wrote:
>>> On 2022-04-16 01:04, Lu Baolu wrote:
>>>> On 2022/4/14 20:42, Robin Murphy wrote:
>>>>> @@ -1883,27 +1900,12 @@ static int iommu_bus_init(struct bus_type
>>>>> *bus)
>>>>> */
>>>>> int bus_set_iommu(struct bus_type *bus, const struct iommu_ops *ops)
>>>>> {
>>>>> - int err;
>>>>> -
>>>>> - if (ops == NULL) {
>>>>> - bus->iommu_ops = NULL;
>>>>> - return 0;
>>>>> - }
>>>>> -
>>>>> - if (bus->iommu_ops != NULL)
>>>>> + if (bus->iommu_ops && ops && bus->iommu_ops != ops)
>>>>> return -EBUSY;
>>>>> bus->iommu_ops = ops;
>>>>
>>>> Do we still need to keep above lines in bus_set_iommu()?
>>>
>>> It preserves the existing behaviour until each callsite and its
>>> associated error handling are removed later on, which seems like as
>>> good a thing to do as any. Since I'm already relaxing
>>> iommu_device_register() to a warn-but-continue behaviour while it
>>> keeps the bus ops on life-support internally, I figured not changing
>>> too much at once would make it easier to bisect any potential issues
>>> arising from this first step.
>>
>> Fair enough. Thank you for the explanation.
>>
>> Do you have a public tree that I could pull these patches and try them
>> on an Intel hardware? Or perhaps you have done this? I like the whole
>> idea of this series, but it's better to try it with a real hardware.
>
> I haven't bothered with separate branches since there's so many
> different pieces in-flight, but my complete (unstable) development
> branch can be found here:
>
> https://gitlab.arm.com/linux-arm/linux-rm/-/commits/iommu/bus
>
> For now I'd recommend winding the head back to "iommu: Clean up
> bus_set_iommu()" for testing - some of the patches above that have
> already been posted and picked up by their respective subsystems, but
> others are incomplete and barely compile-tested. I'll probably rearrange
> it later this week to better reflect what's happened so far.
Okay, thanks for sharing.
Best regards,
baolu
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