xen: Map "xen_nopv" parameter to "nopv" and mark it obsolete

Clean up unnecessory code after that operation.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Signed-off-by: Juergen Gross <jgross@suse.com>

Documentation/admin-guide/kernel-parameters.txt

@@ -5243,6 +5243,8 @@
 	xen_nopv	[X86]
 			Disables the PV optimizations forcing the HVM guest to
 			run as generic HVM guest with no PV drivers.
+			This option is obsoleted by the "nopv" option, which
+			has equivalent effect for XEN platform.
 
 	xen_scrub_pages=	[XEN]
 			Boolean option to control scrubbing pages before giving them back

arch/x86/xen/enlighten_hvm.c

@@ -210,18 +210,18 @@ static void __init xen_hvm_guest_init(void)
 #endif
 }
 
-static bool xen_nopv;
 static __init int xen_parse_nopv(char *arg)
 {
-       xen_nopv = true;
-       return 0;
+	pr_notice("\"xen_nopv\" is deprecated, please use \"nopv\" instead\n");
+
+	if (xen_cpuid_base())
+		nopv = true;
+	return 0;
 }
 early_param("xen_nopv", xen_parse_nopv);
 
 bool __init xen_hvm_need_lapic(void)
 {
-	if (xen_nopv)
-		return false;
 	if (xen_pv_domain())
 		return false;
 	if (!xen_hvm_domain())
@@ -233,7 +233,7 @@ bool __init xen_hvm_need_lapic(void)
 
 static uint32_t __init xen_platform_hvm(void)
 {
-	if (xen_pv_domain() || xen_nopv)
+	if (xen_pv_domain())
 		return 0;
 
 	return xen_cpuid_base();