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The only lock held when a producer is added/removed is irqbypass's mutex. Fixes: 872768800652 ("KVM: x86: select IRQ_BYPASS_MANAGER") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Message-ID: <20250404193923.1413163-5-seanjc@google.com> Signed-off-by: Paolo Bonzini [sean: account for lack of kvm_x86_call()] Signed-off-by: Sean Christopherson --- arch/x86/kvm/x86.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 55185670e0e5..bc52e24f1dda 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -13256,16 +13256,22 @@ int kvm_arch_irq_bypass_add_producer(struct irq_b= ypass_consumer *cons, { struct kvm_kernel_irqfd *irqfd =3D container_of(cons, struct kvm_kernel_irqfd, consumer); + struct kvm *kvm =3D irqfd->kvm; int ret; =20 - irqfd->producer =3D prod; kvm_arch_start_assignment(irqfd->kvm); + + spin_lock_irq(&kvm->irqfds.lock); + irqfd->producer =3D prod; + ret =3D static_call(kvm_x86_pi_update_irte)(irqfd->kvm, prod->irq, irqfd->gsi, 1); - if (ret) kvm_arch_end_assignment(irqfd->kvm); =20 + spin_unlock_irq(&kvm->irqfds.lock); + + return ret; } =20 @@ -13275,9 +13281,9 @@ void kvm_arch_irq_bypass_del_producer(struct irq_by= pass_consumer *cons, int ret; struct kvm_kernel_irqfd *irqfd =3D container_of(cons, struct kvm_kernel_irqfd, consumer); + struct kvm *kvm =3D irqfd->kvm; =20 WARN_ON(irqfd->producer !=3D prod); - irqfd->producer =3D NULL; =20 /* * When producer of consumer is unregistered, we change back to @@ -13285,11 +13291,17 @@ void kvm_arch_irq_bypass_del_producer(struct irq_= bypass_consumer *cons, * when the irq is masked/disabled or the consumer side (KVM * int this case doesn't want to receive the interrupts. */ + spin_lock_irq(&kvm->irqfds.lock); + irqfd->producer =3D NULL; + ret =3D static_call(kvm_x86_pi_update_irte)(irqfd->kvm, prod->irq, irqfd-= >gsi, 0); if (ret) printk(KERN_INFO "irq bypass consumer (token %p) unregistration" " fails: %d\n", irqfd->consumer.token, ret); =20 + spin_unlock_irq(&kvm->irqfds.lock); + + kvm_arch_end_assignment(irqfd->kvm); } =20 --=20 2.51.0.rc1.163.g2494970778-goog