From: Collin Walling <walling@linux.ibm.com>
Date: Thu, 20 Nov 2025 22:34:43 +0000 (-0500)
Subject: qemu: only allow enabling deprecated features that are supported
X-Git-Tag: v11.10.0-rc1~55
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=029933be861be2a8c6c0d55a6cbb3ee0a6419d0a;p=thirdparty%2Flibvirt.git

qemu: only allow enabling deprecated features that are supported

When updating the guest CPU model and the deprecated_features attribute
is set to on, only enable the features the model can actually enable.

While host-model would normally just enable these features without
intervention (and without the presence of the deprecated_features
attribute), custom models would see no changes to their feature set
without these changes.

This is useful for e.g. testing CPU models.

Fixes: f279ea36 (qemu: process: refactor deprecated features code)
Signed-off-by: Collin Walling <walling@linux.ibm.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
---

diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index 2dfdedfa1a..cee7a0f5ef 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -3437,15 +3437,24 @@ virQEMUCapsUpdateCPUDeprecatedFeatures(virQEMUCaps *qemuCaps,
                                        virCPUFeaturePolicy policy)
 {
     qemuMonitorCPUModelInfo *modelInfo;
+    GStrv props;
     size_t i;
 
     modelInfo = virQEMUCapsGetCPUModelInfo(qemuCaps, virtType);
 
-    if (!modelInfo || !modelInfo->full_dep_props)
+    if (!modelInfo)
         return;
 
-    for (i = 0; i < g_strv_length(modelInfo->full_dep_props); i++) {
-        virCPUDefUpdateFeature(cpu, modelInfo->full_dep_props[i], policy);
+    /* Only allow policy "require" on features that are actually
+     * supported on the CPU model */
+    if (policy == VIR_CPU_FEATURE_REQUIRE) {
+        props = modelInfo->static_dep_props;
+    } else {
+        props = modelInfo->full_dep_props;
+    }
+
+    for (i = 0; i < g_strv_length(props); i++) {
+        virCPUDefUpdateFeature(cpu, props[i], policy);
     }
 }