xen: Mark "xen_nopvspin" parameter obsolete

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

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: 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>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 6a8934f..4740d0d 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5712,8 +5712,9 @@
                        panic() code such as dumping handler.
 
        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
@@ -5739,7 +5740,7 @@
                        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 (file)
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -114,9 +114,8 @@ PV_CALLEE_SAVE_REGS_THUNK(xen_vcpu_stolen);
  */
 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;
 }