WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

RE: [Xen-devel] [PATCH 2/3][RFC] MSI/MSI-X support fordom0/driverdomain

To: "Tian, Kevin" <kevin.tian@xxxxxxxxx>, "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx>, "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] [PATCH 2/3][RFC] MSI/MSI-X support fordom0/driverdomain
From: "Tian, Kevin" <kevin.tian@xxxxxxxxx>
Date: Mon, 28 May 2007 20:12:37 +0800
Delivery-date: Mon, 28 May 2007 05:11:00 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <D470B4E54465E3469E2ABBC5AFAC390F013B1E7C@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: Aceg/mz7PRs/d4jlSeu7V67d+hYswQACriSgAACTnuAAAZF9OQAB6/ZAAAEo6AYAAAay8AAAsQtA
Thread-topic: [Xen-devel] [PATCH 2/3][RFC] MSI/MSI-X support fordom0/driverdomain
>From: Tian, Kevin
>Sent: 2007年5月28日 20:04
>
>>From: Keir Fraser [mailto:Keir.Fraser@xxxxxxxxxxxx]
>>Sent: 2007年5月28日 19:48
>>
>>Xen doesn't give a crap about the pirq namespace, except for subtle
>>semantics associated with legacy isa irqs 0-15. Or at least, what little
>>care it does have can (and likely will) be removed. So it's up to dom0
>>whether it wants its pirq namespace to correspond to BIOS-assigned
>>scheme,
>>usual Linux allocation scheme, GSI space, or whatever. This interface
>>will
>>let dom0 control how MSI and INTx is plumbed into its pirq space, if
>>that's
>>what it wants. Other domUs will have no need for an association
>>between
>>their pirq namespace and physical hardware/bios irq numbering -- in
>this
>>case it may make sense to leave it to Xen to do the allocation. But even
>>here, the interface as I described it would allow dom0 to have control
>>over
>>domU allocation too if it wants it.
>>
>> -- Keir
>
>OK, I agree it's flexible and extensible. But is there any real usage
>model pushing on this? For example, is it better for pciback instance
>to allocate pirq space for domU? Pciback can select whether
>passthrough real irq number or allocate from a new space for
>target domain. To let Xen allocate instead makes it complex.

My point is:
        - Xen itself doesn't take any usage of per-domain pirq namespace
        - Dom0 can stick to BIOS-scheme or a new pirq namespace scheme
        - Dom0 can also decide the scheme of domU by pciback

So why not let dom0 to own allocation for pirq namespace of all domains?

Thanks,
Kevin

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel