Drivers: hv: vmbus: Move the check for hypercall page setup

As part of the effort to separate out architecture specific code, move the
check for detecting if the hypercall page is setup.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/x86/hyperv/hv_init.c

@@ -235,3 +235,18 @@ void hyperv_report_panic(struct pt_regs *regs)
 	wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
 }
 EXPORT_SYMBOL_GPL(hyperv_report_panic);
+
+bool hv_is_hypercall_page_setup(void)
+{
+	union hv_x64_msr_hypercall_contents hypercall_msr;
+
+	/* Check if the hypercall page is setup */
+	hypercall_msr.as_uint64 = 0;
+	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+
+	if (!hypercall_msr.enable)
+		return false;
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(hv_is_hypercall_page_setup);

arch/x86/include/asm/mshyperv.h

@@ -115,5 +115,6 @@ void hv_remove_crash_handler(void);
 #if IS_ENABLED(CONFIG_HYPERV)
 void hyperv_init(void);
 void hyperv_report_panic(struct pt_regs *regs);
+bool hv_is_hypercall_page_setup(void);
 #endif
 #endif

drivers/hv/hv.c

@@ -49,7 +49,6 @@ struct hv_context hv_context = {
  */
 int hv_init(void)
 {
-	union hv_x64_msr_hypercall_contents hypercall_msr;
 
 	memset(hv_context.synic_event_page, 0, sizeof(void *) * NR_CPUS);
 	memset(hv_context.synic_message_page, 0,
@@ -65,11 +64,7 @@ int hv_init(void)
 	memset(hv_context.clk_evt, 0,
 	       sizeof(void *) * NR_CPUS);
 
-	/* See if the hypercall page is already set */
-	hypercall_msr.as_uint64 = 0;
-	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
-
-	if (!hypercall_msr.enable)
+	if (!hv_is_hypercall_page_setup())
 		return -ENOTSUPP;
 
 	return 0;