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/
Home Products Support Community News


RE: [Xen-devel] [Q] Is qemu used when we use VTd?

To: "Akio Takebe" <takebe_akio@xxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] [Q] Is qemu used when we use VTd?
From: "Tian, Kevin" <kevin.tian@xxxxxxxxx>
Date: Fri, 12 Sep 2008 11:08:46 +0800
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Thu, 11 Sep 2008 20:09:23 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <48C9DB26.3000609@xxxxxxxxxxxxxx>
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: <48C8F6F2.20305@xxxxxxxxxxxxxx> <D470B4E54465E3469E2ABBC5AFAC390F024D97B1@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> <48C8FBB6.7070305@xxxxxxxxxxxxxx> <D470B4E54465E3469E2ABBC5AFAC390F024D97B9@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> <48C9DB26.3000609@xxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AckUg6dd9Ng0j1/ZSYO0NcOTL//UgAAAJG4w
Thread-topic: [Xen-devel] [Q] Is qemu used when we use VTd?
>From: Akio Takebe [mailto:takebe_akio@xxxxxxxxxxxxxx] 
>Sent: 2008年9月12日 11:00
>Tian, Kevin wrote:
>>> From: Akio Takebe [mailto:takebe_akio@xxxxxxxxxxxxxx] 
>>> Sent: 2008年9月11日 19:07
>>> Hi,
>>> Thank you.
>>> And mmio is traped by hypervisor,
>>> then hypervisor do mmio instead of HVM guest, Right?
>> Which mmio are you actually talking? If you mean MMIO
>> ranges in PCI BARs of passthrough device, they can be
>> directly accessed by HVM with p2m entry setup accord-
>> ingly, if MMIO range falls in 4k page granularity.
>Thank you very much. I talked about MMIO ranges
>in PCI BARs of pass through device using VT-d.
>Does hypervisor trap only MMIO by APIC access?

Hypervisor traps all MMIOs which, if passthrough to HVM,
would generate unexpected result. In other word, you may
simply consider all MMIOs outside of passthrough devices,
including MMIOs of emulated devices, MMIOs of emulated
chispet, and MMIOs from emulated cpus, etc. are trapped
by hypervisor for virtualization. :-)


Xen-devel mailing list