Re: [PATCH v3 05/22] target/i386/monitor: Return QMP error when SEV is disabled in build

[Paolo Bonzini]

On 02/10/21 14:53, Philippe Mathieu-Daudé wrote:
> If the management layer tries to inject a secret, it gets an empty
> response in case the binary built without SEV:
>
>    { "execute": "sev-inject-launch-secret",
>      "arguments": { "packet-header": "mypkt", "secret": "mypass", "gpa": 
> 4294959104 }
>    }
>    {
>        "return": {
>        }
>    }
>
> Make it clearer by returning an error, mentioning the feature is
> disabled:
>
>    { "execute": "sev-inject-launch-secret",
>      "arguments": { "packet-header": "mypkt", "secret": "mypass", "gpa": 
> 4294959104 }
>    }
>    {
>        "error": {
>            "class": "GenericError",
>            "desc": "this feature or command is not currently supported"
>        }
>    }
>
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Reviewed-by: Connor Kuehl <ckuehl@redhat.com>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>   target/i386/monitor.c | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/target/i386/monitor.c b/target/i386/monitor.c
> index 196c1c9e77f..a9f85acd473 100644
> --- a/target/i386/monitor.c
> +++ b/target/i386/monitor.c
> @@ -28,6 +28,7 @@
>   #include "monitor/hmp-target.h"
>   #include "monitor/hmp.h"
>   #include "qapi/qmp/qdict.h"
> +#include "qapi/qmp/qerror.h"
>   #include "sysemu/kvm.h"
>   #include "sysemu/sev.h"
>   #include "qapi/error.h"
> @@ -743,6 +744,10 @@ void qmp_sev_inject_launch_secret(const char *packet_hdr,
>                                     bool has_gpa, uint64_t gpa,
>                                     Error **errp)
>   {
> +    if (!sev_enabled()) {
> +        error_setg(errp, QERR_UNSUPPORTED);
> +        return;
> +    }
>       if (!has_gpa) {
>           uint8_t *data;
>           struct sev_secret_area *area;

This should be done in the sev_inject_launch_secret stub instead, I 
think.  Or if you do it here, you can remove the "if (!sev_guest)" 
conditional in the non-stub version.

Paolo