[PATCH 0/2] vl: fix passing smp options via -readconfig

[PATCH 0/2] vl: fix passing smp options via -readconfig

[Paolo Bonzini]

Even though [smp] does not work in config files, [smp-opts] does
and lxd is using it.  So, fix it.

Paolo Bonzini (2):
  vl: introduce machine_merge_property
  vl: stop recording -smp in QemuOpts

 softmmu/vl.c | 47 +++++++++++++++++++++++++++++++++--------------
 1 file changed, 33 insertions(+), 14 deletions(-)

-- 
2.31.1

[PATCH 1/2] vl: introduce machine_merge_property

[Paolo Bonzini]

It will be used to parse smp-opts config groups from configuration
files.  The point to note is that it does not steal a reference
from the caller.  This is better because this function will be called
from qemu_config_foreach's callback; qemu_config_foreach does not cede
its reference to the qdict to the callback, and wants to free it.  To
balance that extra reference, machine_parse_property_opt now needs
a qobject_unref.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 softmmu/vl.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/softmmu/vl.c b/softmmu/vl.c
index 4dee472c79..93aef8e747 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -1534,23 +1534,36 @@ static void machine_help_func(const QDict *qdict)
     }
 }
 
+static void
+machine_merge_property(const char *propname, QDict *prop, Error **errp)
+{
+    QDict *opts;
+
+    opts = qdict_new();
+    /* Preserve the caller's reference to prop.  */
+    qobject_ref(prop);
+    qdict_put(opts, propname, prop);
+    keyval_merge(machine_opts_dict, opts, errp);
+    qobject_unref(opts);
+}
+
 static void
 machine_parse_property_opt(QemuOptsList *opts_list, const char *propname,
                            const char *arg, Error **errp)
 {
-    QDict *opts, *prop;
+    QDict *prop = NULL;
     bool help = false;
-    ERRP_GUARD();
 
     prop = keyval_parse(arg, opts_list->implied_opt_name, &help, errp);
     if (help) {
         qemu_opts_print_help(opts_list, true);
         exit(0);
     }
-    opts = qdict_new();
-    qdict_put(opts, propname, prop);
-    keyval_merge(machine_opts_dict, opts, errp);
-    qobject_unref(opts);
+    if (!prop) {
+        return;
+    }
+    machine_merge_property(propname, prop, errp);
+    qobject_unref(prop);
 }
 
 static const char *pid_file;
-- 
2.31.1

[PATCH 2/2] vl: stop recording -smp in QemuOpts

[Paolo Bonzini]

-readconfig is still recording SMP options in QemuOpts instead of
using machine_opts_dict.  This means that SMP options from -readconfig
are ignored.

Just stop using QemuOpts for -smp, making it return false for
is_qemuopts_group.  Configuration files will merge the values in
machine_opts_dict using the new function machine_merge_property.

At the same time, fix -mem-prealloc which looked at QemuOpts to find the
number of guest CPUs, which it used as the default number of preallocation
threads.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 softmmu/vl.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/softmmu/vl.c b/softmmu/vl.c
index 93aef8e747..5ca11e7469 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -31,6 +31,7 @@
 #include "qapi/compat-policy.h"
 #include "qapi/error.h"
 #include "qapi/qmp/qdict.h"
+#include "qapi/qmp/qstring.h"
 #include "qapi/qmp/qjson.h"
 #include "qemu-version.h"
 #include "qemu/cutils.h"
@@ -2166,7 +2167,8 @@ static int global_init_func(void *opaque, QemuOpts *opts, Error **errp)
 static bool is_qemuopts_group(const char *group)
 {
     if (g_str_equal(group, "object") ||
-        g_str_equal(group, "machine")) {
+        g_str_equal(group, "machine") ||
+        g_str_equal(group, "smp-opts")) {
         return false;
     }
     return true;
@@ -2186,6 +2188,8 @@ static void qemu_record_config_group(const char *group, QDict *dict,
          */
         assert(!from_json);
         keyval_merge(machine_opts_dict, dict, errp);
+    } else if (g_str_equal(group, "smp-opts")) {
+        machine_merge_property("smp", dict, &error_fatal);
     } else {
         abort();
     }
@@ -2452,13 +2456,15 @@ static void qemu_validate_options(const QDict *machine_opts)
 static void qemu_process_sugar_options(void)
 {
     if (mem_prealloc) {
-        char *val;
-
-        val = g_strdup_printf("%d",
-                 (uint32_t) qemu_opt_get_number(qemu_find_opts_singleton("smp-opts"), "cpus", 1));
-        object_register_sugar_prop("memory-backend", "prealloc-threads", val,
-                                   false);
-        g_free(val);
+        QObject *smp = qdict_get(machine_opts_dict, "smp");
+        if (smp && qobject_type(smp) == QTYPE_QDICT) {
+            QObject *cpus = qdict_get(qobject_to(QDict, smp), "cpus");
+            if (cpus && qobject_type(cpus) == QTYPE_QSTRING) {
+                const char *val = qstring_get_str(qobject_to(QString, cpus));
+                object_register_sugar_prop("memory-backend", "prealloc-threads",
+                                           val, false);
+            }
+        }
         object_register_sugar_prop("memory-backend", "prealloc", "on", false);
     }
 
-- 
2.31.1