Merge branch 'kvm-updates/2.6.33' of git://git.kernel.org/pub/scm/virt/kvm/kvm

* 'kvm-updates/2.6.33' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (84 commits)
  KVM: VMX: Fix comparison of guest efer with stale host value
  KVM: s390: Fix prefix register checking in arch/s390/kvm/sigp.c
  KVM: Drop user return notifier when disabling virtualization on a cpu
  KVM: VMX: Disable unrestricted guest when EPT disabled
  KVM: x86 emulator: limit instructions to 15 bytes
  KVM: s390: Make psw available on all exits, not just a subset
  KVM: x86: Add KVM_GET/SET_VCPU_EVENTS
  KVM: VMX: Report unexpected simultaneous exceptions as internal errors
  KVM: Allow internal errors reported to userspace to carry extra data
  KVM: Reorder IOCTLs in main kvm.h
  KVM: x86: Polish exception injection via KVM_SET_GUEST_DEBUG
  KVM: only clear irq_source_id if irqchip is present
  KVM: x86: disallow KVM_{SET,GET}_LAPIC without allocated in-kernel lapic
  KVM: x86: disallow multiple KVM_CREATE_IRQCHIP
  KVM: VMX: Remove vmx->msr_offset_efer
  KVM: MMU: update invlpg handler comment
  KVM: VMX: move CR3/PDPTR update to vmx_set_cr3
  KVM: remove duplicated task_switch check
  KVM: powerpc: Fix BUILD_BUG_ON condition
  KVM: VMX: Use shared msr infrastructure
  ...

Trivial conflicts due to new Kconfig options in arch/Kconfig and kernel/Makefile

1 files changed, 46 insertions, 0 deletions

diff --git a/kernel/user-return-notifier.c b/kernel/user-return-notifier.c
new file mode 100644
index 000000000000..03e2d6fd9b18
--- /dev/null
+++ b/kernel/user-return-notifier.c
@@ -0,0 +1,46 @@
+
+#include <linux/user-return-notifier.h>
+#include <linux/percpu.h>
+#include <linux/sched.h>
+#include <linux/module.h>
+
+static DEFINE_PER_CPU(struct hlist_head, return_notifier_list);
+
+#define URN_LIST_HEAD per_cpu(return_notifier_list, raw_smp_processor_id())
+
+/*
+ * Request a notification when the current cpu returns to userspace.  Must be
+ * called in atomic context.  The notifier will also be called in atomic
+ * context.
+ */
+void user_return_notifier_register(struct user_return_notifier *urn)
+{
+	set_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY);
+	hlist_add_head(&urn->link, &URN_LIST_HEAD);
+}
+EXPORT_SYMBOL_GPL(user_return_notifier_register);
+
+/*
+ * Removes a registered user return notifier.  Must be called from atomic
+ * context, and from the same cpu registration occured in.
+ */
+void user_return_notifier_unregister(struct user_return_notifier *urn)
+{
+	hlist_del(&urn->link);
+	if (hlist_empty(&URN_LIST_HEAD))
+		clear_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY);
+}
+EXPORT_SYMBOL_GPL(user_return_notifier_unregister);
+
+/* Calls registered user return notifiers */
+void fire_user_return_notifiers(void)
+{
+	struct user_return_notifier *urn;
+	struct hlist_node *tmp1, *tmp2;
+	struct hlist_head *head;
+
+	head = &get_cpu_var(return_notifier_list);
+	hlist_for_each_entry_safe(urn, tmp1, tmp2, head, link)
+		urn->on_user_return(urn);
+	put_cpu_var(return_notifier_list);
+}