From e2a81baf6604a2e08e10c7405b0349106f77c8af Mon Sep 17 00:00:00 2001
From: Jeremy Fitzhardinge <jeremy@goop.org>
Date: Mon, 17 Mar 2008 16:37:17 -0700
Subject: xen: support sysenter/sysexit if hypervisor does

64-bit Xen supports sysenter for 32-bit guests, so support its
use.  (sysenter is faster than int $0x80 in 32-on-64.)

sysexit is still not supported, so we fake it up using iret.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 arch/x86/xen/smp.c | 1 +
 1 file changed, 1 insertion(+)

(limited to 'arch/x86/xen/smp.c')

diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index e340ff92f6b6..d61e4f8b07c7 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -72,6 +72,7 @@ static __cpuinit void cpu_bringup_and_idle(void)
 	int cpu = smp_processor_id();
 
 	cpu_init();
+	xen_enable_sysenter();
 
 	preempt_disable();
 	per_cpu(cpu_state, cpu) = CPU_ONLINE;
-- 
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