cleanup swiotlb initialization

[Boris Ostrovsky]

On 2/24/22 11:39 AM, Christoph Hellwig wrote:
> On Thu, Feb 24, 2022 at 11:18:33AM -0500, Boris Ostrovsky wrote:
>> On 2/24/22 10:58 AM, Christoph Hellwig wrote:
>>> Thanks.
>>>
>>> This looks really strange as early_amd_iommu_init should not interact much
>>> with the changes.  I'll see if I can find a AMD system to test on.
>>
>> Just to be clear: this crashes only as dom0. Boots fine as baremetal.
> Ah.  I can gues what this might be.  On Xen the hypervisor controls the
> IOMMU and we should never end up initializing it in Linux, right?


Right, we shouldn't be in that code path.


-boris