3 files changed, 25 insertions, 4 deletions

diff --git a/arch/x86/kernel/cpu/hypervisor.c b/arch/x86/kernel/cpu/hypervisor.c
index 755f64fb0743..a8f8fa9769d6 100644
--- a/arch/x86/kernel/cpu/hypervisor.c
+++ b/arch/x86/kernel/cpu/hypervisor.c
@@ -37,6 +37,9 @@ static const __initconst struct hypervisor_x86 * const hypervisors[] =
 #endif
 	&x86_hyper_vmware,
 	&x86_hyper_ms_hyperv,
+#ifdef CONFIG_KVM_GUEST
+	&x86_hyper_kvm,
+#endif
 };
 
 const struct hypervisor_x86 *x86_hyper;
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 9473e8772fd1..5e095f873e3e 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -60,8 +60,6 @@ static DEFINE_MUTEX(mce_chrdev_read_mutex);
 
 int mce_disabled __read_mostly;
 
-#define MISC_MCELOG_MINOR	227
-
 #define SPINUNIT 100	/* 100ns */
 
 atomic_t mce_entry;
@@ -2346,7 +2344,7 @@ static __init int mcheck_init_device(void)
 
 	return err;
 }
-device_initcall(mcheck_init_device);
+device_initcall_sync(mcheck_init_device);
 
 /*
  * Old style boot options parsing. Only for compatibility.
diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
index 671b95a2ffb5..c4e916d77378 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
@@ -759,4 +759,24 @@ static __init int threshold_init_device(void)
 
 	return 0;
 }
-device_initcall(threshold_init_device);
+/*
+ * there are 3 funcs which need to be _initcalled in a logic sequence:
+ * 1. xen_late_init_mcelog
+ * 2. mcheck_init_device
+ * 3. threshold_init_device
+ *
+ * xen_late_init_mcelog must register xen_mce_chrdev_device before
+ * native mce_chrdev_device registration if running under xen platform;
+ *
+ * mcheck_init_device should be inited before threshold_init_device to
+ * initialize mce_device, otherwise a NULL ptr dereference will cause panic.
+ *
+ * so we use following _initcalls
+ * 1. device_initcall(xen_late_init_mcelog);
+ * 2. device_initcall_sync(mcheck_init_device);
+ * 3. late_initcall(threshold_init_device);
+ *
+ * when running under xen, the initcall order is 1,2,3;
+ * on baremetal, we skip 1 and we do only 2 and 3.
+ */
+late_initcall(threshold_init_device);