KVM: arm64: nv: Inject a SEA if failed to read the descriptor

Failure to read the descriptor (because it is outside of a memslot) should
result in a SEA being injected in the guest.

Suggested-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/86ms1m9lp3.wl-maz@kernel.org
Signed-off-by: Zenghui Yu (Huawei) <zenghui.yu@linux.dev>
Link: https://patch.msgid.link/20260225173515.20490-4-zenghui.yu@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>

Author: Zenghui Yu (Huawei)

arch/arm64/kvm/nested.c

@@ -296,8 +296,10 @@ static int walk_nested_s2_pgd(struct kvm_vcpu *vcpu, phys_addr_t ipa,
 
 		paddr = base_addr | index;
 		ret = read_guest_s2_desc(vcpu, paddr, &desc, wi);
-		if (ret < 0)
+		if (ret < 0) {
+			out->esr = ESR_ELx_FSC_SEA_TTW(level);
 			return ret;
+		}
 
 		new_desc = desc;