Drivers: hv: vmbus: Add hooks for per-CPU IRQ

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 <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>

Author: kelleymh

arch/x86/include/asm/mshyperv.h

@@ -56,6 +56,10 @@ typedef int (*hyperv_fill_flush_list_func)(
 #define hv_get_raw_timer() rdtsc_ordered()
 #define hv_get_vector() HYPERVISOR_CALLBACK_VECTOR
 
+/* 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) {}
+
 /*
  * Reference to pv_ops must be inline so objtool
  * detection of noinstr violations can work correctly.

drivers/hv/hv.c

@@ -178,6 +178,7 @@ 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 = hv_get_vector();
@@ -235,6 +236,8 @@ 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)