KVM does not hold any references to rcu protected data when it switches CPU into a guest mode. In fact switching to a guest mode is very similar to exiting to userspase from rcu point of view. In addition CPU may stay in a guest mode for quite a long time (up to one time slice). Lets treat guest mode as quiescent state, just like we do with user-mode execution.
Signed-off-by: Gleb Natapov <[email protected]> --- include/linux/kvm_host.h | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 0bc3d37..244413f 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -591,8 +591,17 @@ static inline int kvm_deassign_device(struct kvm *kvm, static inline void kvm_guest_enter(void) { + BUG_ON(preemptible()); account_system_vtime(current); current->flags |= PF_VCPU; + /* KVM does not hold any references to rcu protected data when it + * switches CPU into a guest mode. In fact switching to a guest mode + * is very similar to exiting to userspase from rcu point of view. In + * addition CPU may stay in a guest mode for quite a long time (up to + * one time slice). Lets treat guest mode as quiescent state, just like + * we do with user-mode execution. + */ + rcu_virt_note_context_switch(smp_processor_id()); } static inline void kvm_guest_exit(void) -- 1.7.4.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
