[PATCH 1/5] confidential guest support: Introduce a 'check' class handler

[Cédric Le Goater]

From: Cédric Le Goater <c...@redhat.com>

Some machines have specific requirements to activate confidential
guest support. Add a class handler to the confidential guest support
interface to let the arch implementation perform extra checks.

Cc: Eduardo Habkost <edua...@habkost.net>
Cc: Marcel Apfelbaum <marcel.apfelb...@gmail.com>
Cc: "Philippe Mathieu-Daudé" <phi...@linaro.org>
Cc: Yanan Wang <wangyana...@huawei.com>
Signed-off-by: Cédric Le Goater <c...@redhat.com>
---
 include/exec/confidential-guest-support.h |  4 +++-
 hw/core/machine.c                         | 11 ++++++-----
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/include/exec/confidential-guest-support.h 
b/include/exec/confidential-guest-support.h
index ba2dd4b5df..9e6d362b26 100644
--- a/include/exec/confidential-guest-support.h
+++ b/include/exec/confidential-guest-support.h
@@ -23,7 +23,8 @@
 #include "qom/object.h"
 
 #define TYPE_CONFIDENTIAL_GUEST_SUPPORT "confidential-guest-support"
-OBJECT_DECLARE_SIMPLE_TYPE(ConfidentialGuestSupport, 
CONFIDENTIAL_GUEST_SUPPORT)
+OBJECT_DECLARE_TYPE(ConfidentialGuestSupport, ConfidentialGuestSupportClass,
+                    CONFIDENTIAL_GUEST_SUPPORT)
 
 struct ConfidentialGuestSupport {
     Object parent;
@@ -55,6 +56,7 @@ struct ConfidentialGuestSupport {
 
 typedef struct ConfidentialGuestSupportClass {
     ObjectClass parent;
+    bool (*check)(const Object *obj, Error **errp);
 } ConfidentialGuestSupportClass;
 
 #endif /* !CONFIG_USER_ONLY */
diff --git a/hw/core/machine.c b/hw/core/machine.c
index f589b92909..bab43cd675 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -502,11 +502,12 @@ static void 
machine_check_confidential_guest_support(const Object *obj,
                                                      Object *new_target,
                                                      Error **errp)
 {
-    /*
-     * So far the only constraint is that the target has the
-     * TYPE_CONFIDENTIAL_GUEST_SUPPORT interface, and that's checked
-     * by the QOM core
-     */
+    ConfidentialGuestSupportClass *cgsc =
+        CONFIDENTIAL_GUEST_SUPPORT_GET_CLASS(new_target);
+
+    if (cgsc->check) {
+        cgsc->check(obj, errp);
+    }
 }
 
 static bool machine_get_nvdimm(Object *obj, Error **errp)
-- 
2.38.1