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authorGleb Natapov <gleb@redhat.com>2011-05-04 16:31:04 +0300
committerAvi Kivity <avi@redhat.com>2011-05-22 08:48:09 -0400
commit8fa2206821953a50a3a02ea33fcfb3ced2fd9997 (patch)
treef4f773a0501f0fd8d3bfe30dd4851c9f0095911d /include
parente3aa52d665ec1a962d1cf025a2e5ee84b3b33406 (diff)
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: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'include')
-rw-r--r--include/linux/kvm_host.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 0bc3d372e3c..b9c3299c6a5 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)