[PATCH v6 08/10] Drivers: hv: vmbus: Add hooks for per-CPU IRQ

[Michael Kelley <mikelley@microsoft.com>]

Add hooks to enable/disable a per-CPU IRQ for VMbus. These hooks
are in the architecture independent setup and shutdown paths for
Hyper-V, and are needed by Linux guests on Hyper-V on ARM64.  The
x86/x64 implementation is null because VMbus interrupts on x86/x64
don't use an IRQ.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
---
 arch/x86/include/asm/mshyperv.h | 4 ++++
 drivers/hv/hv.c                 | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 1c42ecb..0e5db78 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -59,6 +59,10 @@ typedef int (*hyperv_fill_flush_list_func)(
 #endif
 void hyperv_vector_handler(struct pt_regs *regs);
 
+/* On x86/x64, there isn't a real IRQ to be enabled/disable */
+static inline void hv_enable_vmbus_irq(void) {}
+static inline void hv_disable_vmbus_irq(void) {}
+
 /*
  * Routines for stimer0 Direct Mode handling.
  * On x86/x64, there are no percpu actions to take.
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 6098e0c..035d3df 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -180,6 +180,7 @@ void hv_synic_enable_regs(unsigned int cpu)
 	hv_set_siefp(siefp.as_uint64);
 
 	/* Setup the shared SINT. */
+	hv_enable_vmbus_irq();
 	hv_get_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
 
 	shared_sint.vector = HYPERVISOR_CALLBACK_VECTOR;
@@ -241,6 +242,8 @@ void hv_synic_disable_regs(unsigned int cpu)
 	hv_get_synic_state(sctrl.as_uint64);
 	sctrl.enable = 0;
 	hv_set_synic_state(sctrl.as_uint64);
+
+	hv_disable_vmbus_irq();
 }
 
 int hv_synic_cleanup(unsigned int cpu)
-- 
1.8.3.1