From 540299d7c8e1946f3af29a632661e3b49cd12fd5 Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Fri, 4 Apr 2014 14:48:04 -0400 Subject: [PATCH] xen/spinlock: Don't enable them unconditionally. commit e0fc17a936334c08b2729fff87168c03fdecf5b6 upstream. The git commit a945928ea2709bc0e8e8165d33aed855a0110279 ('xen: Do not enable spinlocks before jump_label_init() has executed') was added to deal with the jump machinery. Earlier the code that turned on the jump label was only called by Xen specific functions. But now that it had been moved to the initcall machinery it gets called on Xen, KVM, and baremetal - ouch!. And the detection machinery to only call it on Xen wasn't remembered in the heat of merge window excitement. This means that the slowpath is enabled on baremetal while it should not be. Reported-by: Waiman Long Acked-by: Steven Rostedt CC: Boris Ostrovsky Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: David Vrabel Signed-off-by: Greg Kroah-Hartman --- arch/x86/xen/spinlock.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c index 581521c843a5..c570feab9fa2 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -274,7 +274,7 @@ void __init xen_init_spinlocks(void) printk(KERN_DEBUG "xen: PV spinlocks disabled\n"); return; } - + printk(KERN_DEBUG "xen: PV spinlocks enabled\n"); pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(xen_lock_spinning); pv_lock_ops.unlock_kick = xen_unlock_kick; } @@ -290,6 +290,9 @@ static __init int xen_init_spinlocks_jump(void) if (!xen_pvspin) return 0; + if (!xen_domain()) + return 0; + static_key_slow_inc(¶virt_ticketlocks_enabled); return 0; } -- 2.39.2