Re: linux 3.3-pre-rc1: Starting domU fails with Error: Failed to query current memory allocation of dom0.

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Thu, Jan 12, 2012 at 05:05:34PM +0100, Kay Sievers wrote:
> On Thu, Jan 12, 2012 at 16:46, Konrad Rzeszutek Wilk
> <konrad.wilk@oracle.com> wrote:
> > On Thu, Jan 12, 2012 at 01:38:32PM +0100, Sander Eikelenboom wrote:
> 
> >> Today i tried linuses tree of today (last commit is 4c4d285ad5665bfbd983b95fde8d7a477d24a361).
> >>
> >> It boots dom0 fine, but it fails to start any domU with: "Error: Failed to query current memory allocation of dom0."
> >> With my previous 3.1.5 kernel everything is fine, nothing else changed in config in between.
> > Your patch that converts the xen-balloon to use the regular device bus driver
> > (070680218379e15c1901f4bf21b98e3cbf12b527) has some not-so-happy consequences.
> >
> > The toolstack (xen-tools) use:
> >
> > /sys/devices/system/xen_memory/xen_memory0
> >
> > But with the change, it is now:
> >
> > /sys/devices/xen_memory0/target_kb
> 
> Urks, seems like a mistake on my side.
> 
> Please try if changing:
>   bus_unregister(&balloon_subsys);
> to:
>   subsys_system_register(&balloon_subsys, NULL);
> in:
>   drivers/xen/xen-balloon.c
> fixes the issue.

Heh. I was *just* looking at d369a5d8fc70710236ae2d06a0e42dce483712df
("clocksource: convert sysdev_class to a regular subsystem") and typed up this patch
to try it out:


diff --git a/drivers/xen/xen-balloon.c b/drivers/xen/xen-balloon.c
index 3832e30..f0b206e 100644
--- a/drivers/xen/xen-balloon.c
+++ b/drivers/xen/xen-balloon.c
@@ -221,13 +221,13 @@ static int register_balloon(struct device *dev)
 {
 	int i, error;
 
-	error = bus_register(&balloon_subsys);
+	error = subsys_system_register(&balloon_subsys, NULL);
 	if (error)
 		return error;
-
+/*
 	dev->id = 0;
 	dev->bus = &balloon_subsys;
-
+*/
 	error = device_register(dev);
 	if (error) {
 		bus_unregister(&balloon_subsys);
> 
> Sorry for that,

That is OK. That is what rc0 is for.

Anyhow, let me see if that fixes the issue. Thanks for your quick reply.