KVM: SVM: WARN if (de)activating guest mode in IOMMU fails

WARN if (de)activating "guest mode" for an IRTE entry fails as modifying
an IRTE should only fail if KVM is buggy, e.g. has stale metadata.

Link: https://lore.kernel.org/r/20250611224604.313496-48-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index f3bfd7cb0bca5bb9b9774a38517bc198d1f0ba2c..31bf202e0026dc61468c08d53af68c4a0db96649 100644 (file)
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -725,10 +725,9 @@ void avic_apicv_post_state_restore(struct kvm_vcpu *vcpu)
        avic_handle_ldr_update(vcpu);
 }
 
-static int avic_set_pi_irte_mode(struct kvm_vcpu *vcpu, bool activate)
+static void avic_set_pi_irte_mode(struct kvm_vcpu *vcpu, bool activate)
 {
        int apic_id = kvm_cpu_get_apicid(vcpu->cpu);
-       int ret = 0;
        unsigned long flags;
        struct vcpu_svm *svm = to_svm(vcpu);
        struct kvm_kernel_irqfd *irqfd;
@@ -743,16 +742,15 @@ static int avic_set_pi_irte_mode(struct kvm_vcpu *vcpu, bool activate)
                goto out;
 
        list_for_each_entry(irqfd, &svm->ir_list, vcpu_list) {
+               void *data = irqfd->irq_bypass_data;
+
                if (activate)
-                       ret = amd_iommu_activate_guest_mode(irqfd->irq_bypass_data, apic_id);
+                       WARN_ON_ONCE(amd_iommu_activate_guest_mode(data, apic_id));
                else
-                       ret = amd_iommu_deactivate_guest_mode(irqfd->irq_bypass_data);
-               if (ret)
-                       break;
+                       WARN_ON_ONCE(amd_iommu_deactivate_guest_mode(data));
        }
 out:
        spin_unlock_irqrestore(&svm->ir_list_lock, flags);
-       return ret;
 }
 
 static void svm_ir_list_del(struct kvm_kernel_irqfd *irqfd)