Re: [PATCH kernel] powerpc/iommu: Add iommu_ops to report capabilities and allow blocking domains

On 7/12/22 04:46, Jason Gunthorpe wrote:
> On Mon, Jul 11, 2022 at 11:24:32PM +1000, Alexey Kardashevskiy wrote:
> 
>> I really think that for 5.19 we should really move this blocked domain
>> business to Type1 like this:
>>
>> https://github.com/aik/linux/commit/96f80c8db03b181398ad355f6f90e574c3ada4bf
> 
> This creates the same security bug for power we are discussing here. If you

How so? attach_dev() on power makes uninitalizes DMA setup for the group 
on the hardware level, any other DMA user won't be able to initiate DMA.


> don't want to fix it then lets just merge this iommu_ops patch as is rather than
> mangle the core code.

The core code should not be assuming iommu_ops != NULL, Type1 should, I 
thought it is the whole point of having Type1, why is not it the case 
anymore?


-- 
Alexey