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] x2apic mode vs. interrupt remapping

To: Jan Beulich <JBeulich@xxxxxxxxxx>
Subject: RE: [Xen-devel] x2apic mode vs. interrupt remapping
From: "Zhang, Xiantao" <xiantao.zhang@xxxxxxxxx>
Date: Wed, 3 Mar 2010 22:09:12 +0800
Accept-language: en-US
Acceptlanguage: en-US
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, "Cui, Dexuan" <dexuan.cui@xxxxxxxxx>
Delivery-date: Wed, 03 Mar 2010 06:10:07 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4B8E775E0200007800032723@xxxxxxxxxxxxxxxxxx>
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: <4B8E6E3802000078000326ED@xxxxxxxxxxxxxxxxxx> <EB8593BCECAB3D40A8248BE0B6400A38462564F7@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx> <4B8E775E0200007800032723@xxxxxxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: Acq62J6oL1L6CkWIS/uUct5LNFEy6wAAPOjQ
Thread-topic: [Xen-devel] x2apic mode vs. interrupt remapping
When iommu_supports_eim is called in enable_x2apic, drhd is already parsed in 
acpi_boot_init, so iommu_supports_eim should return hardware's real capability. 
That is to say, if eim is no supported on platform, x2apic shouldn't be enabled 
at all. 
Xiantao


Jan Beulich wrote:
>>>> "Zhang, Xiantao" <xiantao.zhang@xxxxxxxxx> 03.03.10 14:32 >>>
>> According to the #Cset20168, x2apic is only enabled when all VT-d
>> engines support IR and EIM support, so the policy should be same
>> with Linux's.
> 
> I would say that c/s has the intended behavior you describe, but since
> iommu_setup() runs after enable_x2apic(), the call to
> iommu_supports_eim() still returns true (iommu_enabled, iommu_qinval,
> and iommu_inremap all have an initial value of 1, and with no drhd
> present the function returns 1.
> 
> Jan


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