[PATCH v4 4/5] KVM: introduce kvm_arch functions for IRQ bypass

[Eric Auger <eric.auger@linaro.org>]

This patch introduces
- kvm_arch_irq_bypass_add_producer
- kvm_arch_irq_bypass_del_producer
- kvm_arch_irq_bypass_stop
- kvm_arch_irq_bypass_start

They make possible to specialize the KVM IRQ bypass consumer in
case CONFIG_KVM_HAVE_IRQ_BYPASS is set.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Feng Wu <feng.wu@intel.com>

---

v2 -> v3 (Feng Wu):
- use 'kvm_arch_irq_bypass_start' instead of 'kvm_arch_irq_bypass_resume'
- Remove 'kvm_arch_irq_bypass_update', which is not needed to be
  a irqbypass callback per Alex's comments.
- Make kvm_arch_irq_bypass_add_producer return 'int'

v1 -> v2:
- use CONFIG_KVM_HAVE_IRQ_BYPASS instead CONFIG_IRQ_BYPASS_MANAGER
- rename all functions according to Paolo's proposal
- add kvm_arch_irq_bypass_update according to Feng's need
---
 include/linux/kvm_host.h | 33 +++++++++++++++++++++++++++++++++
 virt/kvm/Kconfig         |  3 +++
 2 files changed, 36 insertions(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 05e99b8..84b5feb 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -24,6 +24,7 @@
 #include <linux/err.h>
 #include <linux/irqflags.h>
 #include <linux/context_tracking.h>
+#include <linux/irqbypass.h>
 #include <asm/signal.h>
 
 #include <linux/kvm.h>
@@ -1151,5 +1152,37 @@ static inline void kvm_vcpu_set_dy_eligible(struct kvm_vcpu *vcpu, bool val)
 {
 }
 #endif /* CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */
+
+#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
+
+int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *,
+			   struct irq_bypass_producer *);
+void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *,
+			   struct irq_bypass_producer *);
+void kvm_arch_irq_bypass_stop(struct irq_bypass_consumer *);
+void kvm_arch_irq_bypass_start(struct irq_bypass_consumer *);
+
+#else
+
+static inline int kvm_arch_irq_bypass_add_producer(
+			struct irq_bypass_consumer *cons,
+			struct irq_bypass_producer *prod)
+{
+	return -1;
+}
+static inline void kvm_arch_irq_bypass_del_producer(
+			struct irq_bypass_consumer *cons,
+			struct irq_bypass_producer *prod)
+{
+}
+static inline void kvm_arch_irq_bypass_stop(
+			struct irq_bypass_consumer *cons)
+{
+}
+static inline void kvm_arch_irq_bypass_start(
+			struct irq_bypass_consumer *cons)
+{
+}
+#endif /* CONFIG_HAVE_KVM_IRQ_BYPASS */
 #endif
 
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index e2c876d..9f8014d 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -47,3 +47,6 @@ config KVM_GENERIC_DIRTYLOG_READ_PROTECT
 config KVM_COMPAT
        def_bool y
        depends on COMPAT && !S390
+
+config HAVE_KVM_IRQ_BYPASS
+       bool
-- 
1.9.1