Commit 5f02ef74 authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Paolo Bonzini
Browse files

KVM: VMX: switch blocked_vcpu_on_cpu_lock to raw spinlock 



blocked_vcpu_on_cpu_lock is taken from hard interrupt context
(pi_wakeup_handler), therefore it cannot sleep.

Switch it to a raw spinlock.

Fixes:

[41297.066254] BUG: scheduling while atomic: CPU 0/KVM/635218/0x00010001
[41297.066323] Preemption disabled at:
[41297.066324] [<ffffffff902ee47f>] irq_enter_rcu+0xf/0x60
[41297.066339] Call Trace:
[41297.066342]  <IRQ>
[41297.066346]  dump_stack_lvl+0x34/0x44
[41297.066353]  ? irq_enter_rcu+0xf/0x60
[41297.066356]  __schedule_bug.cold+0x7d/0x8b
[41297.066361]  __schedule+0x439/0x5b0
[41297.066365]  ? task_blocks_on_rt_mutex.constprop.0.isra.0+0x1b0/0x440
[41297.066369]  schedule_rtlock+0x1e/0x40
[41297.066371]  rtlock_slowlock_locked+0xf1/0x260
[41297.066374]  rt_spin_lock+0x3b/0x60
[41297.066378]  pi_wakeup_handler+0x31/0x90 [kvm_intel]
[41297.066388]  sysvec_kvm_posted_intr_wakeup_ipi+0x9d/0xd0
[41297.066392]  </IRQ>
[41297.066392]  asm_sysvec_kvm_posted_intr_wakeup_ipi+0x12/0x20
...

Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent df0cc57e

arch/x86/kvm/vmx/posted_intr.c

+8 −8
Original line number Diff line number Diff line
@@ -15,7 +15,7 @@ 
 * can find which vCPU should be waken up.

 */

static DEFINE_PER_CPU(struct list_head, blocked_vcpu_on_cpu);

static DEFINE_PER_CPU(spinlock_t, blocked_vcpu_on_cpu_lock);

static DEFINE_PER_CPU(raw_spinlock_t, blocked_vcpu_on_cpu_lock);



static inline struct pi_desc *vcpu_to_pi_desc(struct kvm_vcpu *vcpu)

{
@@ -121,9 +121,9 @@ static void __pi_post_block(struct kvm_vcpu *vcpu) 
			   new.control) != old.control);



	if (!WARN_ON_ONCE(vcpu->pre_pcpu == -1)) {

		spin_lock(&per_cpu(blocked_vcpu_on_cpu_lock, vcpu->pre_pcpu));

		raw_spin_lock(&per_cpu(blocked_vcpu_on_cpu_lock, vcpu->pre_pcpu));

		list_del(&vcpu->blocked_vcpu_list);

		spin_unlock(&per_cpu(blocked_vcpu_on_cpu_lock, vcpu->pre_pcpu));

		raw_spin_unlock(&per_cpu(blocked_vcpu_on_cpu_lock, vcpu->pre_pcpu));

		vcpu->pre_pcpu = -1;

	}

}
@@ -154,11 +154,11 @@ int pi_pre_block(struct kvm_vcpu *vcpu) 
	local_irq_disable();

	if (!WARN_ON_ONCE(vcpu->pre_pcpu != -1)) {

		vcpu->pre_pcpu = vcpu->cpu;

		spin_lock(&per_cpu(blocked_vcpu_on_cpu_lock, vcpu->pre_pcpu));

		raw_spin_lock(&per_cpu(blocked_vcpu_on_cpu_lock, vcpu->pre_pcpu));

		list_add_tail(&vcpu->blocked_vcpu_list,

			      &per_cpu(blocked_vcpu_on_cpu,

				       vcpu->pre_pcpu));

		spin_unlock(&per_cpu(blocked_vcpu_on_cpu_lock, vcpu->pre_pcpu));

		raw_spin_unlock(&per_cpu(blocked_vcpu_on_cpu_lock, vcpu->pre_pcpu));

	}



	do {
@@ -215,7 +215,7 @@ void pi_wakeup_handler(void) 
	struct kvm_vcpu *vcpu;

	int cpu = smp_processor_id();



	spin_lock(&per_cpu(blocked_vcpu_on_cpu_lock, cpu));

	raw_spin_lock(&per_cpu(blocked_vcpu_on_cpu_lock, cpu));

	list_for_each_entry(vcpu, &per_cpu(blocked_vcpu_on_cpu, cpu),

			blocked_vcpu_list) {

		struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu);
@@ -223,13 +223,13 @@ void pi_wakeup_handler(void) 
		if (pi_test_on(pi_desc) == 1)

			kvm_vcpu_kick(vcpu);

	}

	spin_unlock(&per_cpu(blocked_vcpu_on_cpu_lock, cpu));

	raw_spin_unlock(&per_cpu(blocked_vcpu_on_cpu_lock, cpu));

}



void __init pi_init_cpu(int cpu)

{

	INIT_LIST_HEAD(&per_cpu(blocked_vcpu_on_cpu, cpu));

	spin_lock_init(&per_cpu(blocked_vcpu_on_cpu_lock, cpu));

	raw_spin_lock_init(&per_cpu(blocked_vcpu_on_cpu_lock, cpu));

}



bool pi_has_pending_interrupt(struct kvm_vcpu *vcpu)