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Commit 8fa22068 authored by Gleb Natapov's avatar Gleb Natapov Committed by Avi Kivity
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KVM: make guest mode entry to be rcu quiescent state 



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: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent e3aa52d6

include/linux/kvm_host.h

+9 −0
Original line number Diff line number Diff line
@@ -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)