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Subject[PATCH 5.10 001/563] KVM: VMX: switch blocked_vcpu_on_cpu_lock to raw spinlock
Date
From: Marcelo Tosatti <mtosatti@redhat.com>

commit 5f02ef741a785678930f3ff0a8b6b2b0ef1bb402 upstream.

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: Marcelo Tosatti <mtosatti@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kvm/vmx/posted_intr.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

--- a/arch/x86/kvm/vmx/posted_intr.c
+++ b/arch/x86/kvm/vmx/posted_intr.c
@@ -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_v
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)

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