[Libguestfs] virt-v2v should add kernel console= to Xen->KVM converted guest's grub.conf

[Chuck Anderson]

On Mon, Jan 09, 2012 at 09:18:15AM +0000, Matthew Booth wrote:
> On 01/06/2012 11:48 PM, Chuck Anderson wrote:
>> On Thu, Jan 05, 2012 at 07:10:38PM -0500, Chuck Anderson wrote:
>> --- RedHat.pm.orig	2011-12-08 18:09:16.000000000 -0500
>> +++ RedHat.pm	2012-01-06 18:38:33.224309303 -0500
>> @@ -383,6 +383,15 @@
>>           }
>>       }
>>
>> +    # Add console to any kernel line that doesn't have one
>> +    foreach my $augpath
>> +        ($g->aug_match("/files$grub_conf/title[count(kernel/console) = 0]"))
>> +    {
>> +	my $console_augpath = "$augpath/kernel/console";
>> +	my $console = "ttyS0,115200";
>> +	$g->aug_set($console_augpath, $console);
>> +    }
>> +
>>       eval {
>>           $g->aug_save();
>>       };
>>
>> Would you consider taking such a patch?
>
> We discussed this on IRC on Friday. I don't think we can be quite this  
> simple, because this would be a surprising change for a user  
> intentionally using the graphical console on Xen HVM or VMWare. This is  
> pretty common (in fact I believe most users do this).
>
> We therefore need to special case a Xen PV guest with no kernel console  
> line. This unfortunately won't be as straightforward as this patch  
> because there are currently no hooks in V2V to direct particular  
> features to be enabled during conversion. I agree that we should be  
> doing something like this, though.

We could search for this line in /var/log/dmesg on the guest:

Xen virtual console successfully installed as xvc0

I don't know of any other way to detect the console device in Linux...