mips_malta: Catch kernels linked at wrong address

Add error reporting if the wrong type of kernel is provided for the
current mode of acceleration.

Currently a KVM kernel linked at 0x40000000 can't be used with TCG, and
a normal kernel linked at 0x80000000 can't be used with KVM.

Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Reviewed-by: NAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

hw/mips/mips_malta.c

@@ -792,9 +792,23 @@ static int64_t load_kernel (void)
                 loaderparams.kernel_filename);
         exit(1);
     }
+
+    /* Sanity check where the kernel has been linked */
     if (kvm_enabled()) {
+        if (kernel_entry & 0x80000000ll) {
+            error_report("KVM guest kernels must be linked in useg. "
+                         "Did you forget to enable CONFIG_KVM_GUEST?");
+            exit(1);
+        }
+
         xlate_to_kseg0 = cpu_mips_kvm_um_phys_to_kseg0;
     } else {
+        if (!(kernel_entry & 0x80000000ll)) {
+            error_report("KVM guest kernels aren't supported with TCG. "
+                         "Did you unintentionally enable CONFIG_KVM_GUEST?");
+            exit(1);
+        }
+
         xlate_to_kseg0 = cpu_mips_phys_to_kseg0;
     }