For VTL2 hyperv guest with wakeup mailbox in device tree, don't
overwrite wakeup_secondary_cpu_64 so that the acpi_wakeup_cpu will be
used to bring up the APs.

Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>
---
 arch/x86/hyperv/hv_vtl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c
index 5829aac74f80..09a7410200ba 100644
--- a/arch/x86/hyperv/hv_vtl.c
+++ b/arch/x86/hyperv/hv_vtl.c
@@ -264,7 +264,8 @@ int __init hv_vtl_early_init(void)
 		panic("XSAVE has to be disabled as it is not supported by this module.\n"
 			  "Please add 'noxsave' to the kernel command line.\n");
 
-	apic_update_callback(wakeup_secondary_cpu_64, hv_vtl_wakeup_secondary_cpu);
+	if (!wakeup_mailbox_addr)
+		apic_update_callback(wakeup_secondary_cpu_64, hv_vtl_wakeup_secondary_cpu);
 
 	return 0;
 }
-- 
2.25.1