[PATCH 01/37] iommu: Introduce Shared Virtual Addressing API

[Jean-Philippe Brucker]

On 27/02/18 06:21, Tian, Kevin wrote:
[...]
>> Technically nothing prevents it, but now the resv problem discussed on
>> patch 2/37 stands out. For example on x86 you'd probably need to carve
>> the
>> IOAPIC MSI range out of the process address space. On Arm you'd need to
>> create a write-only mapping for MSIs (IOMMU translates it to the IRQ chip
>> address, but thankfully accessing the doorbell from CPU side doesn't
>> trigger an MSI.)
> 
> so if overlap already exists when binding a process address space
> (since binding may happen much later than creating the process),
> I assume the call will simply fail since carve out at this point is not
> possible?

Yes in this case I think it's safer to abort the bind() call

Thanks,
Jean