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Date: Wed, 28 Feb 2018 16:20:45 +0000
From: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
To: "Tian, Kevin" <kevin.tian@intel.com>,
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Subject: Re: [PATCH 01/37] iommu: Introduce Shared Virtual Addressing API
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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

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