[PATCH v3 52/62] KVM: SVM: WARN if ir_list is non-empty at vCPU free

Sean Christopherson
2025-06-11T22:48:26Z

Now that AVIC IRTE tracking is in a mostly sane state, WARN if a vCPU is
freed with ir_list entries, i.e. if KVM leaves a dangling IRTE.

Initialize the per-vCPU interrupt remapping list and its lock even if AVIC
is disabled so that the WARN doesn't hit false positives (and so that KVM
doesn't need to call into AVIC code for a simple sanity check).

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/svm/avic.c | 5 +++--
arch/x86/kvm/svm/svm.c | 2 ++
2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index d1f7b35c1b02..c55cbb0610b4 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -704,6 +704,9 @@ int avic_init_vcpu(struct vcpu_svm *svm)
int ret;
struct kvm_vcpu *vcpu = &svm->vcpu;

+ INIT_LIST_HEAD(&svm->ir_list);
+ spin_lock_init(&svm->ir_list_lock);
+
if (!enable_apicv || !irqchip_in_kernel(vcpu->kvm))
return 0;

@@ -711,8 +714,6 @@ int avic_init_vcpu(struct vcpu_svm *svm)
if (ret)
return ret;

- INIT_LIST_HEAD(&svm->ir_list);
- spin_lock_init(&svm->ir_list_lock);
svm->dfr_reg = APIC_DFR_FLAT;

return ret;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 56d11f7b4bef..2cd991062acb 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1497,6 +1497,8 @@ static void svm_vcpu_free(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);

+ WARN_ON_ONCE(!list_empty(&svm->ir_list));
+
svm_leave_nested(vcpu);
svm_free_nested(svm);

--
2.50.0.rc1.591.g9c95f17f64-goog