[vfio-users] VM doesn't boot, hangs with R9 Fury passthrough

[Matti Niemenmaa]

On 2015-09-02 20:31, Alex Williamson wrote:
> On Wed, Sep 2, 2015 at 11:22 AM, Matti Niemenmaa <
> matti.niemenmaa+vfio at iki.fi> wrote:
>
>>
>> The source code line pointed to is the WARN_ON in the following snippet in
>> vfio_unmap_unpin (presumably inlined into vfio_remove_dma, which is why
>> only that shows in the trace):
>>
>>                  phys = iommu_iova_to_phys(domain->domain, iova);
>>                  if (WARN_ON(!phys)) {
>>                          iova += PAGE_SIZE;
>>                          continue;
>>                  }
>>
>> As I'm lacking the required low-level knowledge I'll once again simply say
>> that any assistance would be welcomed. I'm glad I made at least some
>> progress, though. :-)
>
> The vfio IOMMU code is being asked to unmap an I/O virtual address (IOVA)
> that was never mapped, which should never happen.  Something is pretty
> broken in the VM or IOMMU if this happens.

Thanks for the insight. Can anything be done about it? What about the 
earlier DMAR error?