Re: [Xen-devel] VT-d flush timeout

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 25/09/14 11:55, Jan Beulich wrote:
>>>> On 25.09.14 at 12:44, <andrew.cooper3@xxxxxxxxxx> wrote:
>> The AMD code will wait for a period of time for the COMMAND_WAIT to
>> start, but not panic() on a timeout.
>>
>> By my reading of the code, amd_iommu_flush_iotlb() can complete without
>> confirming that the iotlbs have actually been flushed, and all that is
>> left behind is an AMD_IOMMU_DEBUG() message.
> Now that you say this I recall having stumbled across this questionable
> behavior in the past (and perhaps even more than once). Certainly
> something for our AMD IOMMU maintainers to look into...
>
> Jan
>

Agreed, although for now I think it is safer to leave ATS disabled.

~Andrew

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