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RE: [Xen-devel] [RFC] Pass-through Interdomain Interrupts Sharing(HVM/Do

To: "Keir Fraser" <keir@xxxxxxxxxxxxx>, "Guy Zana" <guy@xxxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] [RFC] Pass-through Interdomain Interrupts Sharing(HVM/Dom0)
From: "Tian, Kevin" <kevin.tian@xxxxxxxxx>
Date: Fri, 10 Aug 2007 15:15:04 +0800
Cc: Alex Novik <alex@xxxxxxxxxxxx>
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Thread-topic: [Xen-devel] [RFC] Pass-through Interdomain Interrupts Sharing(HVM/Dom0)
>From: Keir raser
>Sent: 2007年8月10日 15:05
>On 10/8/07 08:01, "Keir Fraser" <keir@xxxxxxxxxxxxx> wrote:
>> On 9/8/07 18:45, "Guy Zana" <guy@xxxxxxxxxxxx> wrote:
>>> The main idea here is to inject the interrupt into Dom0 when we don't
>>> know what to do with it. If Dom0 takes the ownership, then let it
>>> the interrupt. If not, we inject it into the HVM. We recognize that all
>>> of the PT devices are not asserting the line by PLINE deassertion or
>>> Dom0 taking the ownership back to it.
>> This needs dom0 kernel changes and does not solve the general
>> problem (among multiple HVM domains, or among HVM domains and
>PV domains
>> other than dom0). Could you somehow track which guest is most likely
>> handle the interrupt, deliver to it first, and then detect the immediate
>> re-interrupt if it EOIs without handling? Plus have a timeout if it does
>> EOI in reasonable time?
>My thought here is a simple priority list with move-to-back of the
>domain when we deliver him the interrupt but he does not deassert the
>either in reasonable time or by the time he EOIs the interrupt. This is
>simple generic logic needing no PV guest changes.
> -- Keir

How is the priority defined?

What's reasonable time for different device requirement?

PV irq sharing takes response from all shared side, and Guy's RFC 
only takes dom0's response. Now your suggestion is much simpler 
toward timeout only, but what do you expect the final performance 
to be?


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