Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

[cascardo/linux.git] / arch / x86 / kernel / kvm.c

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index cc34cec..47190bd 100644 (file)
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -584,6 +584,39 @@ static void kvm_kick_cpu(int cpu)
        kvm_hypercall2(KVM_HC_KICK_CPU, flags, apicid);
 }
 
+
+#ifdef CONFIG_QUEUED_SPINLOCKS
+
+#include <asm/qspinlock.h>
+
+static void kvm_wait(u8 *ptr, u8 val)
+{
+       unsigned long flags;
+
+       if (in_nmi())
+               return;
+
+       local_irq_save(flags);
+
+       if (READ_ONCE(*ptr) != val)
+               goto out;
+
+       /*
+        * halt until it's our turn and kicked. Note that we do safe halt
+        * for irq enabled case to avoid hang when lock info is overwritten
+        * in irq spinlock slowpath and no spurious interrupt occur to save us.
+        */
+       if (arch_irqs_disabled_flags(flags))
+               halt();
+       else
+               safe_halt();
+
+out:
+       local_irq_restore(flags);
+}
+
+#else /* !CONFIG_QUEUED_SPINLOCKS */
+
 enum kvm_contention_stat {
        TAKEN_SLOW,
        TAKEN_SLOW_PICKUP,
@@ -817,6 +850,8 @@ static void kvm_unlock_kick(struct arch_spinlock *lock, __ticket_t ticket)
        }
 }
 
+#endif /* !CONFIG_QUEUED_SPINLOCKS */
+
 /*
  * Setup pv_lock_ops to exploit KVM_FEATURE_PV_UNHALT if present.
  */
@@ -828,8 +863,16 @@ void __init kvm_spinlock_init(void)
        if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT))
                return;
 
+#ifdef CONFIG_QUEUED_SPINLOCKS
+       __pv_init_lock_hash();
+       pv_lock_ops.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath;
+       pv_lock_ops.queued_spin_unlock = PV_CALLEE_SAVE(__pv_queued_spin_unlock);
+       pv_lock_ops.wait = kvm_wait;
+       pv_lock_ops.kick = kvm_kick_cpu;
+#else /* !CONFIG_QUEUED_SPINLOCKS */
        pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(kvm_lock_spinning);
        pv_lock_ops.unlock_kick = kvm_unlock_kick;
+#endif
 }
 
 static __init int kvm_spinlock_init_jump(void)