x86/xen: no need to explicitly register an NMI callback

commit ea9f9274bf4337ba7cbab241c780487651642d63 upstream.

Remove xen_enable_nmi() to fix a 64-bit guest crash when registering
the NMI callback on Xen 3.1 and earlier.

It's not needed since the NMI callback is set by a set_trap_table
hypercall (in xen_load_idt() or xen_write_idt_entry()).

It's also broken since it only set the current VCPU's callback.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 0982233..a6a72ce 100644 (file)
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -574,13 +574,7 @@ void xen_enable_syscall(void)
        }
 #endif /* CONFIG_X86_64 */
 }
-void xen_enable_nmi(void)
-{
-#ifdef CONFIG_X86_64
-       if (register_callback(CALLBACKTYPE_nmi, (char *)nmi))
-               BUG();
-#endif
-}
+
 void __init xen_pvmmu_arch_setup(void)
 {
        HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
@@ -595,7 +589,6 @@ void __init xen_pvmmu_arch_setup(void)
 
        xen_enable_sysenter();
        xen_enable_syscall();
-       xen_enable_nmi();
 }
 
 /* This function is not called for HVM domains */