Re: [PATCH] igvm: populate errp in stub functions

["Daniel P. Berrangé" <berrange@redhat.com>]

On Tue, Jun 09, 2026 at 03:20:14PM +0200, Luigi Leonardi wrote:
> Use error_setg() to report that IGVM is not available, matching
> the pattern used by other stubs in the tree.
> 
> Suggested-by: Stefano Garzarella <sgarzare@redhat.com>
> Signed-off-by: Luigi Leonardi <leonardi@redhat.com>
> ---
>  stubs/igvm.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/stubs/igvm.c b/stubs/igvm.c
> index 9e9f683fc9..dfb85eb548 100644
> --- a/stubs/igvm.c
> +++ b/stubs/igvm.c
> @@ -17,15 +17,18 @@ int qigvm_x86_get_mem_map_entry(int index,
>                                  ConfidentialGuestMemoryMapEntry *entry,
>                                  Error **errp)
>  {
> +    error_setg(errp, "IGVM not supported on this platform");
>      return -1;
>  }
>  
>  int qigvm_x86_set_vp_context(void *data, int index, Error **errp)
>  {
> +    error_setg(errp, "IGVM not supported on this platform");
>      return -1;
>  }
>  
>  int qigvm_directive_madt(QIgvm *ctx, const uint8_t *header_data, Error **errp)
>  {
> +    error_setg(errp, "IGVM not supported on this platform");
>      return -1;
>  }

This is not wrong per-se, so on that  basis

  Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

but are any of these stubs actually reachable when IGVM is not
enabled in the build ? Usually with stubs we find that one
or two methods are the primary entrypoints which must return
an error, at which point everything else becomes unreachable.
The latter cases can just be g_assert_not_reached() as a sanity
check that some unexpected codepath isn't calling in without
checking status earlier. Those would thus would not need
error_setg, nor a 'return' statement.

With regards,
Daniel
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