Re: [PATCH] Allow blktap to be able to be booted assystem volume for PV-on-HVM

["Daniel P. Berrange" <berrange@redhat.com>]

On Mon, Jul 09, 2007 at 02:09:47PM +0900, Kasai Takanori wrote:
> >It also doesn't take account of
> >fact that the device may be named 'xvda' rather than 'hda'.
> 
> I saw the presented patches. The xvdN was forcedly looked like the hdN.
> For example, the hdc is a special device named CDROM in qemu-dm.

No that is wrong. Any hdX device can be a CDROM - whether it is a CDROM
or not is determined by the :cdrom postfix, not the device name.

eg You can happily make hdc a harddisk:

   tap:aio:/var/lib/xen/images/dom.img,hdc,w

Or make hda a CDROM

   tap:aio:/var/lib/xen/images/dom.img,hda:cdrom,w


> Therefore, I think that it should not forcedly do it because it cannot take 
> the consistency.

Being able to use 'xvd*', as well as 'hd*' or 'sd*' as device names is 
important for consistency with paravirt guests, where xvd* is the 
recommended default.

> I think the HVM domain to be should boot on the hda as it is a 
> specification of qemu-dm.

It can do that. My patch made it possible to use either

   tap:aio:/var/lib/xen/images/dom.img,hda,w

Or

   tap:aio:/var/lib/xen/images/dom.img,xvda,w

At the user's choice. 

n/
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