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

From: Raghavendra K T
Date: Sun Oct 13 2013 - 04:09:42 EST


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@xxxxxxxxxxxxxxxxxx>

Ingo,
Could you please take this fix?
This is reviewed by Paolo and Steven.

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