[PATCH v16 33/45] KVM: arm64: WARN on injected undef exceptions

Steven Price <[email protected]> Mon, 3 Aug 2026 14:43:49 +0100
Newsgroups dev.linux.lists.linux-coco,dev.linux.lists.kvmarm,org.infradead.lists.linux-arm-kernel,org.kernel.vger.kvm,org.kernel.vger.linux-kernel
Message-ID <[email protected]>
The RMM doesn't allow injection of a undefined exception into a realm
guest. Add a WARN to catch if this ever happens.

Signed-off-by: Steven Price <[email protected]>
---
Changes since v15:
 * Switch to KVM_BUG() to mark the VM as bugged as well.
Changes since v6:
 * if (x) WARN(1, ...) makes no sense, just WARN(x, ...)!
---
 arch/arm64/kvm/inject_fault.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c
index 6492397b73d7..718419f40c1d 100644
--- a/arch/arm64/kvm/inject_fault.c
+++ b/arch/arm64/kvm/inject_fault.c
@@ -327,6 +327,7 @@ void kvm_inject_size_fault(struct kvm_vcpu *vcpu)
  */
 void kvm_inject_undefined(struct kvm_vcpu *vcpu)
 {
+	KVM_BUG(vcpu_is_rec(vcpu), vcpu->kvm, "Unexpected undefined exception injection to REC");
 	if (vcpu_el1_is_32bit(vcpu))
 		inject_undef32(vcpu);
 	else
-- 
2.43.0