From: David Vrabel <david.vrabel@citrix.com>
Date: Mon, 16 Jun 2014 11:07:00 +0000 (+0200)
Subject: x86/xen: no need to explicitly register an NMI callback
X-Git-Tag: v4.9.8~6022^2~4
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ea9f9274bf4337ba7cbab241c780487651642d63;p=platform%2Fkernel%2Flinux-rpi3.git

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

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>
---

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index bdd22ec..e366b98 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -594,13 +594,7 @@ 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);
@@ -615,7 +609,6 @@ void __init xen_pvmmu_arch_setup(void)
 
 	xen_enable_sysenter();
 	xen_enable_syscall();
-	xen_enable_nmi();
 }
 
 /* This function is not called for HVM domains */