Re: [Xen-devel] QCOW2 goes corrupted when using GPLPV drivers

[James Harper <james.harper@xxxxxxxxxxxxxxxx>]

> 
> QCOW2 disk image gets corrupted when you try to install Service Pack 1
> AFTER installing GPLPV drivers.
> 
> This means, without the pv drivers, everything works fine.
> 
> I tested both RAW and QCOW2 without GPLPV drivers and the installation
> has completed without any error, and the image (at least qcow2) has no
> errors too.
> 
> How to reproduce:
> - Install Windows 7 32-bit guest
> - Check the image with "qemu-img check -f qcow2 -r all" to ensure that
> there still no problems.
> - Install GPLPV drivers 0.11.0.356
> - Try to install Service Pack 1
> - Get an "unknown error" from the installer
> - Check the qcow2 image with "qemu-img check -f qcow2 -r all" and gets
> TONS of integrity errors.
> 

I can't test this just now, but are you saying that the qcow2 volume itself 
goes corrupt as opposed to, say, the filesystem going corrupt?

If 'qemu-img check' is reporting corruption then I guess it has to be the qcow2 
volume... afaik no VM should ever be able to corrupt this so it must be a bug 
in qemu or some other layer like that. I don't know what would be special about 
gplpv that could bring this behaviour out though.

What's your feeling on the sp1 side of things? Do you think it could be just a 
coincidence that it happens during the sp1 install (sp1 install is a pretty big 
operation), or are you confident that it is the installation of sp1 that 
triggers it?

Can you run the debug version of gplpv and try it again then send me the output 
of /var/log/xen/qemu-dm-<domu name>.log?

Also, before you install sp1, please post the output of:

fsutil fsinfo ntfsinfo c:

Someone else may be able to comment on if there is a potential security issue 
with a DomU being able to 'escape' its box and corrupt it's storage container.

Thanks

James


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