[PATCH v5 4/5] xen: Mark "xen_nopvspin" parameter obsolete

[Zhenzhong Duan]

Map "xen_nopvspin" to "nopvspin", fix stale description of "xen_nopvspin"
as we use qspinlock now.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
---
 Documentation/admin-guide/kernel-parameters.txt | 7 ++++---
 arch/x86/xen/spinlock.c                         | 4 ++--
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 89d77ea..df1eacc 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5303,8 +5303,9 @@
 			never -- do not unplug even if version check succeeds
 
 	xen_nopvspin	[X86,XEN]
-			Disables the ticketlock slowpath using Xen PV
-			optimizations.
+			Disables the qspinlock slowpath using Xen PV optimizations.
+			This parameter is obsoleted by "nopvspin" parameter, which
+			has equivalent effect for XEN platform.
 
 	xen_nopv	[X86]
 			Disables the PV optimizations forcing the HVM guest to
@@ -5330,7 +5331,7 @@
 			as generic guest with no PV drivers. Currently support
 			XEN HVM, KVM, HYPER_V and VMWARE guest.
 
-	nopvspin	[X86,KVM]
+	nopvspin	[X86,XEN,KVM]
 			Disables the qspinlock slow path using PV optimizations
 			which allow the hypervisor to 'idle' the guest on lock
 			contention.
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index 6deb490..799f4eb 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -114,9 +114,8 @@ void xen_uninit_lock_cpu(int cpu)
  */
 void __init xen_init_spinlocks(void)
 {
-
 	/*  Don't need to use pvqspinlock code if there is only 1 vCPU. */
-	if (num_possible_cpus() == 1)
+	if (num_possible_cpus() == 1 || nopvspin)
 		xen_pvspin = false;
 
 	if (!xen_pvspin) {
@@ -137,6 +136,7 @@ void __init xen_init_spinlocks(void)
 
 static __init int xen_parse_nopvspin(char *arg)
 {
+	pr_notice("\"xen_nopvspin\" is deprecated, please use \"nopvspin\" instead\n");
 	xen_pvspin = false;
 	return 0;
 }
-- 
1.8.3.1