[PATCH 1/2 v3] kvm: notify host when guest panicked

[Wen Congyang <wency@cn.fujitsu.com>]

The implementation is the same as xen:
register panic notifier, and call hypercall when the guest
is paniced.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
 arch/x86/kernel/kvm.c    |   12 ++++++++++++
 include/linux/kvm_para.h |    1 +
 2 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index f0c6fd6..7f9afc5 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -331,6 +331,17 @@ static struct notifier_block kvm_pv_reboot_nb = {
 	.notifier_call = kvm_pv_reboot_notify,
 };
 
+static int
+kvm_pv_panic_notify(struct notifier_block *nb, unsigned long code, void *unused)
+{
+	kvm_hypercall0(KVM_HC_GUEST_PANICKED);
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block kvm_pv_panic_nb = {
+	.notifier_call = kvm_pv_panic_notify,
+};
+
 static u64 kvm_steal_clock(int cpu)
 {
 	u64 steal;
@@ -417,6 +428,7 @@ void __init kvm_guest_init(void)
 
 	paravirt_ops_setup();
 	register_reboot_notifier(&kvm_pv_reboot_nb);
+	atomic_notifier_chain_register(&panic_notifier_list, &kvm_pv_panic_nb);
 	for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++)
 		spin_lock_init(&async_pf_sleepers[i].lock);
 	if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF))
diff --git a/include/linux/kvm_para.h b/include/linux/kvm_para.h
index ff476dd..d030a22 100644
--- a/include/linux/kvm_para.h
+++ b/include/linux/kvm_para.h
@@ -19,6 +19,7 @@
 #define KVM_HC_MMU_OP			2
 #define KVM_HC_FEATURES			3
 #define KVM_HC_PPC_MAP_MAGIC_PAGE	4
+#define KVM_HC_GUEST_PANICKED		5
 
 /*
  * hypercalls use architecture specific
-- 
1.7.1