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From:   Zhenzhong Duan <zhenzhong.duan@oracle.com>
To:     linux-kernel@vger.kernel.org
Cc:     vkuznets@redhat.com, linux-hyperv@vger.kernel.org,
        kvm@vger.kernel.org, kys@microsoft.com, haiyangz@microsoft.com,
        sthemmin@microsoft.com, sashal@kernel.org, tglx@linutronix.de,
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        boris.ostrovsky@oracle.com, jgross@suse.com,
        sstabellini@kernel.org, peterz@infradead.org,
        Zhenzhong Duan <zhenzhong.duan@oracle.com>,
        Jonathan Corbet <corbet@lwn.net>,
        "H. Peter Anvin" <hpa@zytor.com>
Subject: [PATCH v4 3/4] xen: Mark "xen_nopvspin" parameter obsolete
Date:   Thu,  3 Oct 2019 22:02:14 +0800
Message-Id: <1570111335-12731-4-git-send-email-zhenzhong.duan@oracle.com>
In-Reply-To: <1570111335-12731-1-git-send-email-zhenzhong.duan@oracle.com>
References: <1570111335-12731-1-git-send-email-zhenzhong.duan@oracle.com>
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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>
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>
---
 Documentation/admin-guide/kernel-parameters.txt | 7 ++++---
 arch/x86/xen/spinlock.c                         | 3 +++
 2 files changed, 7 insertions(+), 3 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..bae29a4 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -114,6 +114,8 @@ void xen_uninit_lock_cpu(int cpu)
  */
 void __init xen_init_spinlocks(void)
 {
+	if (nopvspin)
+		xen_pvspin = false;
 
 	/*  Don't need to use pvqspinlock code if there is only 1 vCPU. */
 	if (num_possible_cpus() == 1)
@@ -137,6 +139,7 @@ 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