Re: [Xen-devel] PCI-passthrough for 32 bit guests and high MMIO addresses

[David Vrabel <david.vrabel@xxxxxxxxxx>]

On 21/11/14 15:38, Jan Beulich wrote:
>>>> On 21.11.14 at 16:01, <andrew.cooper3@xxxxxxxxxx> wrote:
>> On 21/11/14 14:54, Jan Beulich wrote:
>>>>>> On 21.11.14 at 15:39, <JGross@xxxxxxxx> wrote:
>>>> Trying to do PCI-passthrough with a 32-bit pv-domain I passed the
>>>> wrong device to the domain. The MMIO address was too large for a
>>>> MFN of a 32-bit system (it was 380003200000-3800036fffff).
>>>>
>>>> Instead of rejecting the operation Xen tried to perform it resulting
>>>> in a (quite understandable) failure in the domU.
>>>>
>>>> I think either the hypervisor or the tools should refuse to do
>>>> PCI-passthrough in this case.
>>> What's wrong with this large an address?
>>
>> It is wider than 44 bits, so doesn't fit in a 32bit pfn for p2m/m2p
>> update operations.
> 
> MMIO regions don't go into these tables.

They do in upstream kernels.

David

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