Re: loadvm: "Error -1 while loading VM state"

[Soren Hansen <soren@ubuntu.com>]

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On Tue, Jul 01, 2008 at 10:27:19PM +0300, Slohm Gadaburi wrote:
> I can't get qemu/kvm to loadvm a saved state.

This is a known issue. We applied a patch to fix a security problem in
kvm that allowed guests to write outside the boundaries of the
designated disk image. savevm works by writing the snapshot data at the
end of qcow2 files, which is conveniently located just outside
aforementioned boundary. This means that the savevm actually fails, but
that error is never reported back to the user and everythings seems to
be in working order. However, when you try to loadvm, you'll notice that
the snapshot was never actually saved.  

I fixed this in Ubuntu Intrepid (our upcoming release) and Debian
unstable by simply allowing writes outside the disk image boundaries if
the guest isn't running. I sent the updated security patch back to the
original source (Dan Berrange from RedHat), but I'm not sure what
happened after that.

FWIW, the preferred way to save VM state (or to use KVM at all, really)
in Ubuntu is through libvirt/virt-manager anyway, but this bug really
should be fixed. It's on my todo-queue somewhere, but that queue is
rather long, I'm afraid.

You're welcome on the ubuntu-server mailing list with these questions by
the way. You can see how to subscribe here:

   http://lists.ubuntu.com/ubuntu-server

-- 
Soren Hansen               | 
Virtualisation specialist  | Ubuntu Server Team
Canonical Ltd.             | http://www.ubuntu.com/

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