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] HVM windows - PCI IRQ firing on both CPU's

To: "Keir Fraser" <keir.fraser@xxxxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] HVM windows - PCI IRQ firing on both CPU's
From: "James Harper" <james.harper@xxxxxxxxxxxxxxxx>
Date: Mon, 18 Aug 2008 22:32:02 +1000
Cc:
Delivery-date: Mon, 18 Aug 2008 05:32:24 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <C4CF291A.26177%keir.fraser@xxxxxxxxxxxxx>
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/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <AEC6C66638C05B468B556EA548C1A77D01490333@trantor> <C4CF291A.26177%keir.fraser@xxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AckBIKaFdOX6QU6hSgaQozLRUZxMrQACj3ysAABk+0AAAE37LgAACjsw
Thread-topic: [Xen-devel] HVM windows - PCI IRQ firing on both CPU's
> 
> On 18/8/08 13:19, "James Harper" <james.harper@xxxxxxxxxxxxxxxx>
wrote:
> 
> > Just so I understand, even if I see the IRQ on CPU1, I should always
> > treat it as if it came in on CPU0?
> 
> Yes. Only vcpu0's event-channel logic is wired into the virtual
> PIC/IOAPIC.
> Even if the IOAPIC then forwards the interrupt to a different VCPU,
it's
> still vcpu0's event-channel status that initiated the interrupt. Other
> vcpus' event-channel statuses do not cause interrupts in HVM.
> 

I'm not sure if this is a general or a windows specific question, but I
can approach this in one of two ways...

1. Make sure the interrupt is only ever delivered to CPU0 by specifying
the affinity when I call IoConnectInterrupt
2. Accept the interrupt on any CPU but always use vcpu_info[0] to check
the flags etc.

Does the hypervisor make any scheduling assumptions upon delivering an
event to a domain? (eg does it schedule CPU0 on the basis that that CPU
is going to be handling the event?)

Thanks

James

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