Signed-off-by: Peter Zijlstra <pet...@infradead.org>
---
arch/x86/kernel/kvm.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++
kernel/Kconfig.locks | 2 -
2 files changed, 59 insertions(+), 1 deletion(-)
Index: linux-2.6/arch/x86/kernel/kvm.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/kvm.c
+++ linux-2.6/arch/x86/kernel/kvm.c
@@ -569,6 +569,7 @@ static void kvm_kick_cpu(int cpu)
kvm_hypercall2(KVM_HC_KICK_CPU, flags, apicid);
}
+#ifndef CONFIG_QUEUE_SPINLOCK
enum kvm_contention_stat {
TAKEN_SLOW,
TAKEN_SLOW_PICKUP,
@@ -796,6 +797,51 @@ static void kvm_unlock_kick(struct arch_
}
}
}
+#else /* QUEUE_SPINLOCK */
+
+#include <asm-generic/qspinlock.h>
+
+PV_CALLEE_SAVE_REGS_THUNK(__pv_init_node);
+PV_CALLEE_SAVE_REGS_THUNK(__pv_link_and_wait_node);
+PV_CALLEE_SAVE_REGS_THUNK(__pv_kick_node);
+
+PV_CALLEE_SAVE_REGS_THUNK(__pv_wait_head);
+PV_CALLEE_SAVE_REGS_THUNK(__pv_queue_unlock);
+
+void kvm_wait(int *ptr, int val)
+{
+ unsigned long flags;
+
+ if (in_nmi())
+ return;
+
+ /*
+ * Make sure an interrupt handler can't upset things in a
+ * partially setup state.
+ */
+ local_irq_save(flags);
+
+ /*
+ * check again make sure it didn't become free while
+ * we weren't looking.
+ */
+ if (ACCESS_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);
+}
+#endif /* QUEUE_SPINLOCK */
/*
* Setup pv_lock_ops to exploit KVM_FEATURE_PV_UNHALT if present.
@@ -808,8 +854,20 @@ void __init kvm_spinlock_init(void)
if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT))
return;
+#ifdef CONFIG_QUEUE_SPINLOCK
+ pv_lock_ops.init_node = PV_CALLEE_SAVE(__pv_init_node);
+ pv_lock_ops.link_and_wait_node =
PV_CALLEE_SAVE(__pv_link_and_wait_node);
+ pv_lock_ops.kick_node = PV_CALLEE_SAVE(__pv_kick_node);
+
+ pv_lock_ops.wait_head = PV_CALLEE_SAVE(__pv_wait_head);
+ pv_lock_ops.queue_unlock = PV_CALLEE_SAVE(__pv_queue_unlock);
+
+ pv_lock_ops.wait = kvm_wait;
+ pv_lock_ops.kick = kvm_kick_cpu;
+#else
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)
Index: linux-2.6/kernel/Kconfig.locks
===================================================================
--- linux-2.6.orig/kernel/Kconfig.locks
+++ linux-2.6/kernel/Kconfig.locks
@@ -229,7 +229,7 @@ config ARCH_USE_QUEUE_SPINLOCK
config QUEUE_SPINLOCK
def_bool y if ARCH_USE_QUEUE_SPINLOCK
- depends on SMP && !PARAVIRT_SPINLOCKS
+ depends on SMP && !(PARAVIRT_SPINLOCKS && XEN)
config ARCH_USE_QUEUE_RWLOCK
bool
--
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