KVM: make guest mode entry to be rcu quiescent state (8fa22068) · Commits · 戴 / test

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 <gleb@redhat.com> Signed-off-by:

Avi Kivity <avi@redhat.com>

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)

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