From 6bad6ecc63b75af294ff3f56f54d6b857c8964a5 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 1 Apr 2025 08:47:26 -0700 Subject: [PATCH] KVM: VMX: Assert that IRQs are disabled when putting vCPU on PI wakeup list Assert that IRQs are already disabled when putting a vCPU on a CPU's PI wakeup list, as opposed to saving/disabling+restoring IRQs. KVM relies on IRQs being disabled until the vCPU task is fully scheduled out, i.e. until the scheduler has dropped all of its per-CPU locks (e.g. for the runqueue), as attempting to wake the task while it's being scheduled out could lead to deadlock. Signed-off-by: Sean Christopherson Reviewed-by: Maxim Levitsky Reviewed-by: Yan Zhao Message-ID: <20250401154727.835231-2-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/posted_intr.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c index ec08fa3caf43c..840d435229a87 100644 --- a/arch/x86/kvm/vmx/posted_intr.c +++ b/arch/x86/kvm/vmx/posted_intr.c @@ -148,9 +148,8 @@ static void pi_enable_wakeup_handler(struct kvm_vcpu *vcpu) struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); struct vcpu_vmx *vmx = to_vmx(vcpu); struct pi_desc old, new; - unsigned long flags; - local_irq_save(flags); + lockdep_assert_irqs_disabled(); raw_spin_lock(&per_cpu(wakeup_vcpus_on_cpu_lock, vcpu->cpu)); list_add_tail(&vmx->pi_wakeup_list, @@ -176,8 +175,6 @@ static void pi_enable_wakeup_handler(struct kvm_vcpu *vcpu) */ if (pi_test_on(&new)) __apic_send_IPI_self(POSTED_INTR_WAKEUP_VECTOR); - - local_irq_restore(flags); } static bool vmx_needs_pi_wakeup(struct kvm_vcpu *vcpu)