[PATCH v12 28/46] KVM: arm64: WARN on injected undef exceptions

From: Steven Price

Date: Wed Dec 17 2025 - 05:31:03 EST


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 <steven.price@xxxxxxx>
Reviewed-by: Gavin Shan <gshan@xxxxxxxxxx>
---
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 5e00f7a69bcc..22bd9258665b 100644
--- a/arch/arm64/kvm/inject_fault.c
+++ b/arch/arm64/kvm/inject_fault.c
@@ -289,6 +289,7 @@ void kvm_inject_size_fault(struct kvm_vcpu *vcpu)
*/
void kvm_inject_undefined(struct kvm_vcpu *vcpu)
{
+ WARN(vcpu_is_rec(vcpu), "Unexpected undefined exception injection to REC");
if (vcpu_el1_is_32bit(vcpu))
inject_undef32(vcpu);
else
--
2.43.0