KVM: Drop kvm->irq_lock lock from irq injection path

The only thing it protects now is interrupt injection into lapic and
this can work lockless. Even now with kvm->irq_lock in place access
to lapic is not entirely serialized since vcpu access doesn't take
kvm->irq_lock.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 0 insertions, 2 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index fdf989f17a61..5beb4c16caab 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2286,10 +2286,8 @@ long kvm_arch_vm_ioctl(struct file *filp,
                         goto out;
                 if (irqchip_in_kernel(kvm)) {
                         __s32 status;
-                        mutex_lock(&kvm->irq_lock);
                         status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
                                         irq_event.irq, irq_event.level);
-                        mutex_unlock(&kvm->irq_lock);
                         if (ioctl == KVM_IRQ_LINE_STATUS) {
                                 irq_event.status = status;
                                 if (copy_to_user(argp, &irq_event,