Re: [PATCH v6 10/10] i386/pc: restrict AMD only enforcing of valid IOVAs to new machine type

[Joao Martins]

On 7/4/22 15:27, Dr. David Alan Gilbert wrote:
> * Joao Martins (joao.m.martins@oracle.com) wrote:
>> The added enforcing is only relevant in the case of AMD where the
>> range right before the 1TB is restricted and cannot be DMA mapped
>> by the kernel consequently leading to IOMMU INVALID_DEVICE_REQUEST
>> or possibly other kinds of IOMMU events in the AMD IOMMU.
>>
>> Although, there's a case where it may make sense to disable the
>> IOVA relocation/validation when migrating from a
>> non-valid-IOVA-aware qemu to one that supports it.
>>
>> Relocating RAM regions to after the 1Tb hole has consequences for
>> guest ABI because we are changing the memory mapping, so make
>> sure that only new machine enforce but not older ones.
>>
>> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> 
> Thanks for keeping the migration compatibility, so for migration:
> 
> Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> 

Thank you!