Question: PV and HVM device list

Question: PV and HVM device list

[Hu Jia Yi]

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I have two questions about xen. Hope I can find answers/hints in this
mailing list.

 

1. how PV and HVM know about what physical devices are in the PC? 

2. If a USB disk is plugged in, how does xen notify this to PV and HVM
so that the guest domains can do things as there were no virtualization
layer.

 

Best regards,

Hu Jia Yi

Ext: 20430

Tel: 65-67510430

 


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Re: Question: PV and HVM device list

[Daniel P. Berrange]

On Wed, Sep 05, 2007 at 02:13:58PM +0800, Hu Jia Yi wrote:
> I have two questions about xen. Hope I can find answers/hints in this
> mailing list.
> 
> 1. how PV and HVM know about what physical devices are in the PC? 

They typically don't know anything about physical hardware. Normal practice
is to only assign virtual devices to guests - virtual network / disk or
sound & USB devices are most common (the latter two for HVM only).

> 2. If a USB disk is plugged in, how does xen notify this to PV and HVM
> so that the guest domains can do things as there were no virtualization
> layer.

Xen doesn't do anything when USB disks are plugged in. It is possible use
admin tools to explicitly map a USB disk through to a guest as a virtual
disk, or in HVM case to hand-off the entire USB device to the guest. This
is a manual admin config step though - nothing automatic occurrs.

Dan.
-- 
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RE: Question: PV and HVM device list

[Hu Jia Yi]

May I know which source files I should read if I want to know how 
Xen assigns virtual devices to guest? I suspect "the asms file is
needed"
problem in installing winxp is because CD-rom is not assigned to winxp
when the winxp HVM domain is restarted.

Best regards,
Hu Jia Yi
Ext: 20430
Tel: 65-67510430

-----Original Message-----
From: Daniel P. Berrange [mailto:berrange@redhat.com] 
Sent: Wednesday, September 05, 2007 11:43 PM
To: Hu Jia Yi
Cc: xen-devel@lists.xensource.com
Subject: Re: [Xen-devel] Question: PV and HVM device list

On Wed, Sep 05, 2007 at 02:13:58PM +0800, Hu Jia Yi wrote:
> I have two questions about xen. Hope I can find answers/hints in this
> mailing list.
> 
> 1. how PV and HVM know about what physical devices are in the PC? 

They typically don't know anything about physical hardware. Normal
practice
is to only assign virtual devices to guests - virtual network / disk or
sound & USB devices are most common (the latter two for HVM only).

> 2. If a USB disk is plugged in, how does xen notify this to PV and HVM
> so that the guest domains can do things as there were no
virtualization
> layer.

Xen doesn't do anything when USB disks are plugged in. It is possible
use
admin tools to explicitly map a USB disk through to a guest as a virtual
disk, or in HVM case to hand-off the entire USB device to the guest.
This
is a manual admin config step though - nothing automatic occurrs.
553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505  -=|