Re: [Xen-devel] [Draft F] Xen on ARM vITS Handling

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Ian,

On 12/06/2015 04:52, Ian Campbell wrote:
> On Fri, 2015-06-12 at 14:07 +0530, Vijay Kilari wrote:
> So pLPIs must be routed at device assignment time because in the vLPI
> configuration table trap there is no mapping back to a single pLPI.
I just remembered the exact reason that made use to differ SPI enabling.
When the device is assigned, the domain VCPUs are still down (even VCPU0).

If we receive an interrupt before the VCPU0 is unpaused, the interrupt 
will be lost. Same if the interrupt is not yet configured (i.e before 
the vITS setup correctly the table) with your proposal.
This could happen when the device is not quiescent. We had this issue on 
the vexpress at boot time when the network card was trying to send an 
interrupt before DOM0 is setup.
Regards,

--
Julien Grall

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