[PATCH 09/14] hw: temporarily disable deletion of versioned machine types

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

The new deprecation and deletion policy for versioned machine types is
being introduced in QEMU 9.1.0.

Under the new policy a number of old machine types (any prior to 2.12)
would be liable for immediate deletion which would be a violation of our
historical deprecation and removal policy

Thus automatic deletions (by skipping QOM registration) are temporarily
gated on existance of the env variable "QEMU_DELETE_MACHINES" / QEMU
version number >= 10.1.0. This allows opt-in testing of the automatic
deletion logic, while activating it fully in QEMU >= 10.1.0.

This whole commit should be reverted in the 10.1.0 dev cycle or shortly
thereafter.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 include/hw/boards.h | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/include/hw/boards.h b/include/hw/boards.h
index 48b6c98c77..d6214007ce 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -657,10 +657,28 @@ struct MachineState {
         } \
     } while (0)
 
+/*
+ * The new deprecation and deletion policy for versioned
+ * machine types was introduced in QEMU 9.1.0.
+ *
+ * Under the new policy a number of old machine types (any
+ * prior to 2.12) would be liable for immediate deletion
+ * which would be a violation of our historical deprecation
+ * and removal policy
+ *
+ * Thus deletions are temporarily gated on existance of
+ * the env variable "QEMU_DELETE_MACHINES" / QEMU version
+ * number >= 10.1.0. This gate can be deleted in the 10.1.0
+ * dev cycle
+ */
 #define MACHINE_VER_DELETION(...) \
     do { \
         if (MACHINE_VER_SHOULD_DELETE(__VA_ARGS__)) { \
-            return; \
+            if (getenv("QEMU_DELETE_MACHINES") || \
+                QEMU_VERSION_MAJOR > 10 || (QEMU_VERSION_MAJOR == 10 && \
+                                            QEMU_VERSION_MINOR >= 1)) { \
+                return; \
+            } \
         } \
     } while (0)
 
-- 
2.43.0