Re: [PATCH] kvm fix: Enable pvspinlock after jump_label_init() to avoid VM hang

Gleb Natapov
2013-10-13T08:11:16Z

On Sun, Oct 13, 2013 at 01:38:57PM +0530, Raghavendra K T wrote:
> On 10/09/2013 02:33 PM, Raghavendra K T wrote:
> >We use jump label to enable pv-spinlock. With the changes in
> >(442e0973e927 Merge branch 'x86/jumplabel'), the jump label behaviour has changed
> >that would result in evntual hang of the VM since we would end up in a situation
> >where slowpath locks would halt the vcpus but we will not be able to wakeup the
> >vcpu by lock releaser using unlock kick.
> >
> >Similar problem in Xen and more detailed description is available in
> >a945928ea270 (xen: Do not enable spinlocks before jump_label_init() has executed)
> >
> >This patch splits kvm_spinlock_init to separate jump label changes with pvops
> >patching and also make jump label enabling after jump_label_init().
> >
> >Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
>
> Ingo,
> Could you please take this fix?
> This is reviewed by Paolo and Steven.
It's KVM, I'll take it.

--
Gleb.