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Commit 34226b6b authored by Wanpeng Li's avatar Wanpeng Li Committed by Radim Krčmář
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KVM: X86: Fix setup the virt_spin_lock_key before static key get initialized 



 static_key_disable_cpuslocked(): static key 'virt_spin_lock_key+0x0/0x20' used before call to jump_label_init()
 WARNING: CPU: 0 PID: 0 at kernel/jump_label.c:161 static_key_disable_cpuslocked+0x61/0x80
 RIP: 0010:static_key_disable_cpuslocked+0x61/0x80
 Call Trace:
  static_key_disable+0x16/0x20
  start_kernel+0x192/0x4b3
  secondary_startup_64+0xa5/0xb0

Qspinlock will be choosed when dedicated pCPUs are available, however, the
static virt_spin_lock_key is set in kvm_spinlock_init() before jump_label_init()
has been called, which will result in a WARN(). This patch fixes it by delaying
the virt_spin_lock_key setup to .smp_prepare_cpus().

Reported-by: default avatarDavidlohr Bueso <dbueso@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: default avatarWanpeng Li <wanpengli@tencent.com>
Fixes: b2798ba0 ("KVM: X86: Choose qspinlock when dedicated physical CPUs are available")
Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
parent 1f97e01a

arch/x86/kernel/kvm.c

+9 −3
Original line number Diff line number Diff line
@@ -454,6 +454,13 @@ static void __init sev_map_percpu_data(void) 
}



#ifdef CONFIG_SMP

static void __init kvm_smp_prepare_cpus(unsigned int max_cpus)

{

	native_smp_prepare_cpus(max_cpus);

	if (kvm_para_has_hint(KVM_HINTS_DEDICATED))

		static_branch_disable(&virt_spin_lock_key);

}



static void __init kvm_smp_prepare_boot_cpu(void)

{

	/*
@@ -557,6 +564,7 @@ static void __init kvm_guest_init(void) 
		kvm_setup_vsyscall_timeinfo();



#ifdef CONFIG_SMP

	smp_ops.smp_prepare_cpus = kvm_smp_prepare_cpus;

	smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;

	if (cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/kvm:online",

				      kvm_cpu_online, kvm_cpu_down_prepare) < 0)
@@ -737,10 +745,8 @@ void __init kvm_spinlock_init(void) 
	if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT))

		return;



	if (kvm_para_has_hint(KVM_HINTS_DEDICATED)) {

		static_branch_disable(&virt_spin_lock_key);

	if (kvm_para_has_hint(KVM_HINTS_DEDICATED))

		return;

	}



	__pv_init_lock_hash();

	pv_lock_ops.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath;