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

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

On Fri, 2015-06-12 at 09:09 -0400, Julien Grall wrote:
> 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.

I can't parse this sentence, differ how?

> 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.

Is this any different to booting with the ITT not setup?

(SPIs are a slightly different case because they don't need h/w routing)

> 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.

I don't fully understand the issue you are trying to describe, but do
you want to propose a change to the spec?

Ian.


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