[Fedora-xen] 2.6.38-rc dom0 kernel and xen 4.1.0-rc2

[Pasi Kärkkäinen]

On Thu, Jan 27, 2011 at 05:03:57PM -0600, W. Michael Petullo wrote:
> >> Now, the last issue remaining for me is the backend drivers. My
> >> understanding is that, in the absence of backends being accepted
> >> upstream, we can use QEMU-based drivers. This would be acceptable for
> >> our work. Has anyone been using these with Fedora 15?
>  
> > In theory the block driver should work in 4.1.0, though I am not
> > sure about the net driver. In practise I have failed so far to get
> > the block driver working so far. This post today
> > http://lists.xensource.com/archives/html/xen-devel/2011-01/msg01847.html
> > talks about what block driver configurations should work.
> 
> I have written the following domain config (to try to force the QEMU
> block backend):
> 
> kernel   =   '/tmp/openwrt-x86-xen_domu-vmlinuz'
> memory   =    32
> # NOTE: Generated with qemu-img convert -f raw -O qcow2 input.img output.qcow2
> disk     = [ 'tap:qcow2:/tmp/openwrt-x86-xen_domu-rootfs-ext2.qcow2,xvda,r', ]
> vif      = [ 'bridge=virbr0' ]
> name     =   '2.6.38-DomU-Test'
> root     =   '/dev/xvda1'
> on_crash =   'destroy'
> 
> When I boot, I get:
> 
> [...]
> NET: Registered protocol family 17
> 802.1Q VLAN Support v1.8 Ben Greear <greearb at candelatech.com>
> All bugs added by David S. Miller <davem at redhat.com>
> Using IPI No-Shortcut mode
> XENBUS: Waiting for devices to initialise: 295s...290s...285s...280s...
> 
> When I try to use:
> 
> disk     = [ 'file:/tmp/openwrt-x86-xen_domu-rootfs-ext2.img,xvda,r', ]
> 
> I get:
> 
> [No boot]
> Error: Device 51712 (vbd) could not be connected. Path closed or removed during hotplug add: backend/vbd/13/51712 state: 1
> 

Just making sure.. you're running Xen 4.1 ?
The userspace qemu blkback implementation is *only* in Xen 4.1 ..

And it should get used automatically if dom0 kernel blkback is not available.

-- Pasi