Re: [PATCH][tip] x86/paravirt: Make the virt_spin_lock_key setup after jump_label_init()

From: Boris Petkov
Date: Fri Oct 27 2017 - 12:52:15 EST


On October 27, 2017 6:02:00 PM GMT+02:00, Dou Liyang <douly.fnst@xxxxxxxxxxxxxx> wrote:
>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 xx_smp_prepare_cpus(). Make the
>setup later to avoid the WARN().
>
>Reported-by: Juergen Gross <jgross@xxxxxxxx>
>Suggested-by: Juergen Gross <jgross@xxxxxxxx>
>Signed-off-by: Dou Liyang <douly.fnst@xxxxxxxxxxxxxx>
>---
> arch/x86/kernel/smpboot.c | 3 ++-
> arch/x86/xen/smp_pv.c | 2 ++
> arch/x86/xen/spinlock.c | 6 ++++--
> 3 files changed, 8 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/smp_pv.c b/arch/x86/xen/smp_pv.c
>index 5147140..570b2bc 100644
>--- a/arch/x86/xen/smp_pv.c
>+++ b/arch/x86/xen/smp_pv.c
>@@ -236,6 +236,8 @@ static void __init xen_pv_smp_prepare_cpus(unsigned
>int max_cpus)
> xen_raw_printk(m);
> panic(m);
> }
>+ native_pv_lock_init();
>+
> xen_init_lock_cpu(0);
>
> smp_store_boot_cpu_info();
>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);

This is assuming CPU 0 is the boot cpu. I think you want boot_cpu_data.cpu_index here or whatever is used on xen to identify the BSP reliably.


--
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