[Xen-devel] [PATCH tip v2] x86/paravirt: Make the virt_spin_lock_key setup after jump_label_init()

[Dou Liyang <douly.fnst@xxxxxxxxxxxxxx>]

Commit:

  9043442b43b1 ("locking/paravirt: Use new static key for controlling
  call of virt_spin_lock()")

set the static virt_spin_lock_key to a value before jump_label_init()
has been called, which will result in a WARN().

Move the native_pv_lock_init() into native_smp_prepare_cpus(), and set
the value in xen_init_lock_cpu() to make the setup later and avoid the
WARN().

Reported-by: Juergen Gross <jgross@xxxxxxxx>
Suggested-by: Juergen Gross <jgross@xxxxxxxx>
Signed-off-by: Dou Liyang <douly.fnst@xxxxxxxxxxxxxx>
Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
---
changelog:
  v1-->v2: remove the native_pv_lock_init() from xen_pv_smp_prepare_cpus(),
  It is redundant, suggested by Juergen.

---
 arch/x86/kernel/smpboot.c | 3 ++-
 arch/x86/xen/spinlock.c   | 6 ++++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index aed1460..6b1335a 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1323,6 +1323,8 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)
        pr_info("CPU0: ");
        print_cpu_info(&cpu_data(0));
 
+       native_pv_lock_init();
+
        uv_system_init();
 
        set_mtrr_aps_delayed_init();
@@ -1350,7 +1352,6 @@ void __init native_smp_prepare_boot_cpu(void)
        /* already set me in cpu_online_mask in boot_cpu_init() */
        cpumask_set_cpu(me, cpu_callout_mask);
        cpu_set_state_online(me);
-       native_pv_lock_init();
 }
 
 void __init native_smp_cpus_done(unsigned int max_cpus)
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index e8ab80a..1e1462d 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -81,8 +81,11 @@ void xen_init_lock_cpu(int cpu)
        int irq;
        char *name;
 
-       if (!xen_pvspin)
+       if (!xen_pvspin) {
+               if (cpu == 0)
+                       static_branch_disable(&virt_spin_lock_key);
                return;
+       }
 
        WARN(per_cpu(lock_kicker_irq, cpu) >= 0, "spinlock on CPU%d exists on 
IRQ%d!\n",
             cpu, per_cpu(lock_kicker_irq, cpu));
@@ -130,7 +133,6 @@ void __init xen_init_spinlocks(void)
 
        if (!xen_pvspin) {
                printk(KERN_DEBUG "xen: PV spinlocks disabled\n");
-               static_branch_disable(&virt_spin_lock_key);
                return;
        }
        printk(KERN_DEBUG "xen: PV spinlocks enabled\n");
-- 
2.5.5




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