[Qemu-devel] [Patch v1 26/29] qmp: add QMP interface "query-cpu-model-baseline"

[David Hildenbrand <dahi@linux.vnet.ibm.com>]

Let's provide a standardized interface to baseline two CPU models, to
create a third, compatible one.

The returned CPU model is a static CPU model, so it will never change
between QEMU machines.

Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
---
 include/sysemu/arch_init.h            |  3 +++
 qapi-schema.json                      | 38 +++++++++++++++++++++++++++++++++++
 qmp-commands.hx                       |  6 ++++++
 qmp.c                                 |  7 +++++++
 stubs/Makefile.objs                   |  1 +
 stubs/arch-query-cpu-model-baseline.c | 12 +++++++++++
 6 files changed, 67 insertions(+)
 create mode 100644 stubs/arch-query-cpu-model-baseline.c

diff --git a/include/sysemu/arch_init.h b/include/sysemu/arch_init.h
index 96d47c0..1c9dad1 100644
--- a/include/sysemu/arch_init.h
+++ b/include/sysemu/arch_init.h
@@ -41,5 +41,8 @@ CpuModelExpansionInfo *arch_query_cpu_model_expansion(CpuModelExpansionType type
 CpuModelCompareInfo *arch_query_cpu_model_comparison(CpuModelInfo *modela,
                                                      CpuModelInfo *modelb,
                                                      Error **errp);
+CpuModelBaselineInfo *arch_query_cpu_model_baseline(CpuModelInfo *modela,
+                                                    CpuModelInfo *modelb,
+                                                    Error **errp);
 
 #endif
diff --git a/qapi-schema.json b/qapi-schema.json
index 1f8f8ec..4e21a86 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -3214,6 +3214,44 @@
   'data': { 'modela': 'CpuModelInfo', 'modelb': 'CpuModelInfo' },
   'returns': 'CpuModelCompareInfo' }
 
+##
+# @CpuModelBaselineInfo
+#
+# The result of a CPU model baseline.
+#
+# @model: the baselined CpuModelInfo.
+#
+# Since: 2.8.0
+##
+{ 'struct': 'CpuModelBaselineInfo',
+  'data': { 'model': 'CpuModelInfo' } }
+
+##
+# @query-cpu-model-baseline:
+#
+# Baseline two CPU models, creating a compatible third model. The created
+# model will always be a static, migration-safe CPU model (see "static"
+# CPU model expansion for details). The QEMU machine QEMU has been started
+# with affects the result if CPU definitions are used that are not static.
+#
+# Note: This interface should not be used when global properties of CPU classes
+#       are changed (e.g. via "-cpu ...").
+#
+# s390x supports baselining of all CPU models. Other architectures are not
+# supported yet.
+#
+# Returns: a CpuModelBaselineInfo. Returns an error if baselining CPU models is
+#          not supported, if a model cannot be used, if a model contains
+#          an unknown cpu definition name, unknown properties or properties
+#          with wrong types.
+#
+# Since: 2.8.0
+##
+{ 'command': 'query-cpu-model-baseline',
+  'data': { 'modela': 'CpuModelInfo',
+            'modelb': 'CpuModelInfo' },
+  'returns': 'CpuModelBaselineInfo' }
+
 # @AddfdInfo:
 #
 # Information about a file descriptor that was added to an fd set.
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 0af2098..8abccb9 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -3954,6 +3954,12 @@ EQMP
     },
 
     {
+        .name       = "query-cpu-model-baseline",
+        .args_type  = "modela:q,modelb:q",
+        .mhandler.cmd_new = qmp_marshal_query_cpu_model_baseline,
+    },
+
+    {
         .name       = "query-target",
         .args_type  = "",
         .mhandler.cmd_new = qmp_marshal_query_target,
diff --git a/qmp.c b/qmp.c
index f551019..dea8f81 100644
--- a/qmp.c
+++ b/qmp.c
@@ -621,6 +621,13 @@ CpuModelCompareInfo *qmp_query_cpu_model_comparison(CpuModelInfo *modela,
     return arch_query_cpu_model_comparison(modela, modelb, errp);
 }
 
+CpuModelBaselineInfo *qmp_query_cpu_model_baseline(CpuModelInfo *modela,
+                                                   CpuModelInfo *modelb,
+                                                   Error **errp)
+{
+    return arch_query_cpu_model_baseline(modela, modelb, errp);
+}
+
 void qmp_add_client(const char *protocol, const char *fdname,
                     bool has_skipauth, bool skipauth, bool has_tls, bool tls,
                     Error **errp)
diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
index da768f0..c5850e8 100644
--- a/stubs/Makefile.objs
+++ b/stubs/Makefile.objs
@@ -1,6 +1,7 @@
 stub-obj-y += arch-query-cpu-def.o
 stub-obj-y += arch-query-cpu-model-expansion.o
 stub-obj-y += arch-query-cpu-model-comparison.o
+stub-obj-y += arch-query-cpu-model-baseline.o
 stub-obj-y += bdrv-next-monitor-owned.o
 stub-obj-y += blk-commit-all.o
 stub-obj-y += blockdev-close-all-bdrv-states.o
diff --git a/stubs/arch-query-cpu-model-baseline.c b/stubs/arch-query-cpu-model-baseline.c
new file mode 100644
index 0000000..094ec13
--- /dev/null
+++ b/stubs/arch-query-cpu-model-baseline.c
@@ -0,0 +1,12 @@
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "sysemu/arch_init.h"
+#include "qapi/qmp/qerror.h"
+
+CpuModelBaselineInfo *arch_query_cpu_model_baseline(CpuModelInfo *modela,
+                                                    CpuModelInfo *modelb,
+                                                    Error **errp)
+{
+    error_setg(errp, QERR_UNSUPPORTED);
+    return NULL;
+}
-- 
2.6.6