Re: [PATCH 1/4] s390/kvm: Handle hosts not supporting s390-virtio.

[Cornelia Huck <cornelia.huck@de.ibm.com>]

On Thu, 09 Aug 2012 13:03:57 +0300
Avi Kivity <avi@redhat.com> wrote:

> On 08/07/2012 05:52 PM, Cornelia Huck wrote:
> > Running under a kvm host does not necessarily imply the presence of
> > a page mapped above the main memory with the virtio information;
> > however, the code includes a hard coded access to that page.
> > 
> > Instead, check for the presence of the page and exit gracefully
> > before we hit an addressing exception if it does not exist.
> > 
> >  /*
> >   * Init function for virtio
> >   * devices are in a single page above top of "normal" mem
> > @@ -443,6 +458,12 @@ static int __init kvm_devices_init(void)
> >  	}
> >  
> >  	kvm_devices = (void *) real_memory_size;
> > +	if (test_devices_support() < 0) {
> > +		vmem_remove_mapping(real_memory_size, PAGE_SIZE);
> > +		root_device_unregister(kvm_root);
> > +		/* No error. */
> > +		return 0;
> > +	}
> >  
> 
> Cleaner to defer root_device_register() until after the mapping has been
> verified.

OK, will reorder.