libvirt/libvirt-cpu-Introduce-virCPUUpdateFeatures.patch

From 353e7eb26cb922bd342c050273afbcc4ed4dd20e Mon Sep 17 00:00:00 2001
Message-ID: <353e7eb26cb922bd342c050273afbcc4ed4dd20e.1780571167.git.jdenemar@redhat.com>
From: Jiri Denemark <jdenemar@redhat.com>
Date: Mon, 25 May 2026 14:22:58 +0200
Subject: [PATCH] cpu: Introduce virCPUUpdateFeatures

This new API can be used to update an existing CPU definition with
features described by CPU data.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
(cherry picked from commit 6be1be4938338477bff14ff24c7ed2a05bc1dadc)

https://redhat.atlassian.net/browse/RHEL-177364

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 src/cpu/cpu.c            | 34 ++++++++++++++++++++++++++++++++++
 src/cpu/cpu.h            | 12 ++++++++++++
 src/cpu/cpu_x86.c        | 23 +++++++++++++++++++++++
 src/libvirt_private.syms |  1 +
 4 files changed, 70 insertions(+)

diff --git a/src/cpu/cpu.c b/src/cpu/cpu.c
index d81e620a1d..3e9affa1cd 100644
--- a/src/cpu/cpu.c
+++ b/src/cpu/cpu.c
@@ -1359,6 +1359,40 @@ virCPUGetCanonicalModel(virArch arch,
 }
 
 
+/** virCPUUpdateFeatures:
+ *
+ * @arch: CPU architecture
+ * @cpu: CPU definition to update
+ * @cpuData: CPU data describing features
+ * @policy: to be used by the updated features
+ *
+ * Updates features described in @cpuData to use the specified @policy. Missing
+ * features will be automatically added to the CPU definition.
+ *
+ * Returns 0 on success, -1 otherwise.
+ */
+int
+virCPUUpdateFeatures(virArch arch,
+                     virCPUDef *cpu,
+                     virCPUData *cpuData,
+                     virCPUFeaturePolicy policy)
+{
+    struct cpuArchDriver *driver;
+
+    VIR_DEBUG("arch=%s, cpu=%p, model=%s, policy=%s",
+              virArchToString(arch), cpu, NULLSTR(cpu->model),
+              virCPUFeaturePolicyTypeToString(policy));
+
+    if (!(driver = cpuGetSubDriver(arch)))
+        return -1;
+
+    if (!driver->updateFeatures)
+        return 0;
+
+    return driver->updateFeatures(cpu, cpuData, policy);
+}
+
+
 /**
  * virCPUArchIsSupported:
  *
diff --git a/src/cpu/cpu.h b/src/cpu/cpu.h
index 36fd123675..65711ac085 100644
--- a/src/cpu/cpu.h
+++ b/src/cpu/cpu.h
@@ -143,6 +143,11 @@ typedef int
 typedef const char *
 (*virCPUArchGetCanonicalModel)(const char *model);
 
+typedef int
+(*virCPUArchUpdateFeatures)(virCPUDef *cpu,
+                            virCPUData *cpuData,
+                            virCPUFeaturePolicy policy);
+
 struct cpuArchDriver {
     const char *name;
     const virArch *arch;
@@ -172,6 +177,7 @@ struct cpuArchDriver {
     virCPUArchDataGetHost dataGetHost;
     virCPUArchGetCheckMode getCheckMode;
     virCPUArchGetCanonicalModel getCanonicalModel;
+    virCPUArchUpdateFeatures updateFeatures;
 };
 
 
@@ -332,6 +338,12 @@ const char *
 virCPUGetCanonicalModel(virArch arch,
                         const char *model);
 
+int
+virCPUUpdateFeatures(virArch arch,
+                     virCPUDef *cpu,
+                     virCPUData *cpuData,
+                     virCPUFeaturePolicy policy);
+
 bool
 virCPUArchIsSupported(virArch arch);
 
diff --git a/src/cpu/cpu_x86.c b/src/cpu/cpu_x86.c
index e5825fbb4d..6e860de458 100644
--- a/src/cpu/cpu_x86.c
+++ b/src/cpu/cpu_x86.c
@@ -3790,6 +3790,28 @@ virCPUx86GetCanonicalModel(const char *modelName)
 }
 
 
+static int
+virCPUx86UpdateFeatures(virCPUDef *cpu,
+                        virCPUData *cpuData,
+                        virCPUFeaturePolicy policy)
+{
+    virCPUx86Data *data = &cpuData->data.x86;
+    virCPUx86Map *map;
+    size_t i;
+
+    if (!(map = virCPUx86GetMap()))
+        return -1;
+
+    for (i = 0; i < map->nfeatures; i++) {
+        virCPUx86Feature *feature = map->features[i];
+        if (x86DataIsSubset(data, &feature->data))
+            virCPUDefUpdateFeature(cpu, feature->name, policy);
+    }
+
+    return 0;
+}
+
+
 struct cpuArchDriver cpuDriverX86 = {
     .name = "x86",
     .arch = archs,
@@ -3824,4 +3846,5 @@ struct cpuArchDriver cpuDriverX86 = {
 #endif
     .getCheckMode = virCPUx86GetCheckMode,
     .getCanonicalModel = virCPUx86GetCanonicalModel,
+    .updateFeatures = virCPUx86UpdateFeatures,
 };
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 3eb6943440..4a0f9065fa 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1586,6 +1586,7 @@ virCPUGetVendorForModel;
 virCPUProbeHost;
 virCPUTranslate;
 virCPUUpdate;
+virCPUUpdateFeatures;
 virCPUUpdateLive;
 virCPUValidateFeatures;
 
-- 
2.54.0