hw/acpi: Move QMP command to hw/core/

The QERR_ macros are leftovers from the days of "rich" error objects.
We've been trying to reduce their remaining use.

qmp_query_vm_generation_id() in stubs/vmgenid.c is the last user of
QERR_UNSUPPORTED outside qga/.  Unlike the stubs we just dropped, it
is actually reachable, namely when CONFIG_ACPI_VMGENID is off.  It
always fails like

    (qemu) info vm-generation-id
    Error: this feature or command is not currently supported

Turns out the real qmp_query_vm_generation_id() doesn't actually
depend on CONFIG_ACPI_VMGENID, and fails safely when it's off.  Move
it to hw/core/machine-qmp-cmds.c, and drop the stub.  The error
message becomes

    Error: VM Generation ID device not found

Feels like an improvement to me.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230207075115.1525-8-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/hw/core/machine-qmp-cmds.c b/hw/core/machine-qmp-cmds.c
index 44b5da8..a6ed3a6 100644
--- a/hw/core/machine-qmp-cmds.c
+++ b/hw/core/machine-qmp-cmds.c
@@ -8,6 +8,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "hw/acpi/vmgenid.h"
 #include "hw/boards.h"
 #include "hw/intc/intc.h"
 #include "hw/mem/memory-device.h"
@@ -383,3 +384,20 @@ HumanReadableText *qmp_x_query_irq(Error **errp)
 
     return human_readable_text_from_str(buf);
 }
+
+GuidInfo *qmp_query_vm_generation_id(Error **errp)
+{
+    GuidInfo *info;
+    VmGenIdState *vms;
+    Object *obj = find_vmgenid_dev();
+
+    if (!obj) {
+        error_setg(errp, "VM Generation ID device not found");
+        return NULL;
+    }
+    vms = VMGENID(obj);
+
+    info = g_malloc0(sizeof(*info));
+    info->guid = qemu_uuid_unparse_strdup(&vms->guid);
+    return info;
+}