KVM: arm64: Set IL for injected FPAC exceptions during ERET emulation

The FPAC syndrome constructed during nested ERET emulation does not set
IL. For FPAC (EC=0x1C), IL reflects the instruction length. ERET and
its authenticated variants are always A64 32-bit instructions, so IL
must be 1.

Fixes: 213b3d1ea161 ("KVM: arm64: nv: Handle ERETA[AB] instructions")
Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://patch.msgid.link/20260618121643.4105064-5-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
index 96ebe7e3b408106bc8c51121bb469b4b59da0e80..a15b2f41a12c81bcbd81844ed8cb0bce2fe15f9c 100644 (file)
--- a/arch/arm64/kvm/emulate-nested.c
+++ b/arch/arm64/kvm/emulate-nested.c
@@ -2800,7 +2800,7 @@ void kvm_emulate_nested_eret(struct kvm_vcpu *vcpu)
                 * ERET handling, and the guest will have a little surprise.
                 */
                if (kvm_has_pauth(vcpu->kvm, FPACCOMBINE) && !(spsr & PSR_IL_BIT)) {
-                       esr &= ESR_ELx_ERET_ISS_ERETA;
+                       esr &= (ESR_ELx_ERET_ISS_ERETA | ESR_ELx_IL);
                        esr |= FIELD_PREP(ESR_ELx_EC_MASK, ESR_ELx_EC_FPAC);
                        kvm_inject_nested_sync(vcpu, esr);
                        return;