Re: [libvirt] [Qemu-devel] [PATCH for-2.9 17/17] target-i386: Implement query-cpu-model-expansion QMP command

On Tue, Dec 13, 2016 at 11:16:01AM +0100, Markus Armbruster wrote: > Eduardo Habkost <ehabkost(a)redhat.com&gt; writes: > > > Implement query-cpu-model-expansion for target-i386. > > > > The code needs to be careful to handle non-migration-safe > > features ("pmu" and "host-cache-info") according to the expansion > > type. > > > > Cc: libvir-list(a)redhat.com > > Cc: Jiri Denemark <jdenemar(a)redhat.com&gt; > > Signed-off-by: Eduardo Habkost <ehabkost(a)redhat.com&gt; > > --- > > tests/Makefile.include | 3 + > > monitor.c | 4 +- > > target-i386/cpu.c | 195 ++++++++++++++++++++++++++++++++++++++++++++++++- > > 3 files changed, 200 insertions(+), 2 deletions(-) > > > > diff --git a/tests/Makefile.include b/tests/Makefile.include > > index 63c4347..c7bbfca 100644 > > --- a/tests/Makefile.include > > +++ b/tests/Makefile.include > > @@ -251,6 +251,9 @@ check-qtest-x86_64-y += $(check-qtest-i386-y) > > gcov-files-i386-y += i386-softmmu/hw/timer/mc146818rtc.c > > gcov-files-x86_64-y = $(subst i386-softmmu/,x86_64-softmmu/,$(gcov-files-i386-y)) > > > > +check-simpleqtest-x86_64-y += $(SRC_PATH)/tests/query-cpu-model-test.py > > +check-simpleqtest-i386-y += $(SRC_PATH)/tests/query-cpu-model-test.py > > + > > check-qtest-alpha-y = tests/boot-serial-test$(EXESUF) > > > > check-qtest-mips-y = tests/endianness-test$(EXESUF) > > diff --git a/monitor.c b/monitor.c > > index 0841d43..90c12b3 100644 > > --- a/monitor.c > > +++ b/monitor.c > > @@ -983,8 +983,10 @@ static void qmp_unregister_commands_hack(void) > > #ifndef TARGET_ARM > > qmp_unregister_command("query-gic-capabilities"); > > #endif > > -#if !defined(TARGET_S390X) > > +#if !defined(TARGET_S390X) && !defined(TARGET_I386) > > qmp_unregister_command("query-cpu-model-expansion"); > > +#endif > > +#if !defined(TARGET_S390X) > > qmp_unregister_command("query-cpu-model-baseline"); > > qmp_unregister_command("query-cpu-model-comparison"); > > #endif > > diff --git a/target-i386/cpu.c b/target-i386/cpu.c > > index bf4ac09..198014a 100644 > > --- a/target-i386/cpu.c > > +++ b/target-i386/cpu.c > > @@ -29,10 +29,14 @@ > > #include "qemu/option.h" > > #include "qemu/config-file.h" > > #include "qapi/qmp/qerror.h" > > +#include "qapi/qmp/qstring.h" > > +#include "qapi/qmp/qdict.h" > > +#include "qapi/qmp/qbool.h" > > > > #include "qapi-types.h" > > #include "qapi-visit.h" > > #include "qapi/visitor.h" > > +#include "qom/qom-qobject.h" > > #include "sysemu/arch_init.h" > > > > #if defined(CONFIG_KVM) > > @@ -2259,7 +2263,7 @@ static void x86_cpu_apply_props(X86CPU *cpu, PropValue *props) > > } > > } > > > > -/* Load data from X86CPUDefinition > > +/* Load data from X86CPUDefinition into a X86CPU object > > */ > > static void x86_cpu_load_def(X86CPU *cpu, X86CPUDefinition *def, Error **errp) > > { > > @@ -2268,6 +2272,11 @@ static void x86_cpu_load_def(X86CPU *cpu, X86CPUDefinition *def, Error **errp) > > char host_vendor[CPUID_VENDOR_SZ + 1]; > > FeatureWord w; > > > > + /*NOTE: any property set by this function should be returned by > > Space between /* and comment text, please. > > Also, consider adding wings to both ends of multi-line comments. Will do. > > > + * x86_cpu_to_dict(), so CPU model data returned by > > + * query-cpu-model-expansion is always complete. > > + */ > > + > > /* CPU models only set _minimum_ values for level/xlevel: */ > > object_property_set_int(OBJECT(cpu), def->level, "min-level", errp); > > object_property_set_int(OBJECT(cpu), def->xlevel, "min-xlevel", errp); > > @@ -2312,6 +2321,190 @@ static void x86_cpu_load_def(X86CPU *cpu, X86CPUDefinition *def, Error **errp) > > > > } > > > > +/* Convert CPU model data from X86CPU object to a property dictionary > > + * that can recreate exactly the same CPU model. > > + * > > + * This function does the opposite of x86_cpu_load_def(). Any > > + * property changed by x86_cpu_load_def() or instance_init > > + * methods should be returned by this function too. > > + */ > > +static void x86_cpu_to_dict(X86CPU *cpu, QDict *props, Error **errp) > > +{ > > + Object *obj = OBJECT(cpu); > > + FeatureWord w; > > + PropValue *pv; > > + > > + /* This code could simply iterate over all writeable properties in the > > + * CPU object, and return all of them. But then the aliases properties > > "alias properties"? Will fix it. > > > + * would be returned as well. Returning only the known features > > + * is more reliable. > > + */ > > + qdict_put_obj(props, "min-level", > > + object_property_get_qobject(obj, "min-level", errp)); > > + qdict_put_obj(props, "min-xlevel", > > + object_property_get_qobject(obj, "min-xlevel", errp)); > > + > > + qdict_put_obj(props, "family", > > + object_property_get_qobject(obj, "family", errp)); > > + qdict_put_obj(props, "model", > > + object_property_get_qobject(obj, "model", errp)); > > + qdict_put_obj(props, "stepping", > > + object_property_get_qobject(obj, "stepping", errp)); > > + qdict_put_obj(props, "model-id", > > + object_property_get_qobject(obj, "model-id", errp)); > > Incorrect use of the error API: if more than one call fails, the second > failure will trip the assertion in error_setv(). > > If errors should not happen here, use &error_abort. > > If errors need to be handled, see "Receive and accumulate multiple > errors" in error.h. > Oops. I will fix it. > Consider "more than four, use a for": > > static char *prop_name[] = { > "min-level", "min-xlevel", "family", "model", "stepping", > "model-id", NULL > }; > > for (pname = prop_name; *pname, pname++) { > qdict_put_obj(props, *pname, > object_property_get_qobject(obj, *pname, > &error_abort)); > } Good idea, I will do it. > > > + > > + for (w = 0; w < FEATURE_WORDS; w++) { > > + FeatureWordInfo *fi = &feature_word_info[w]; > > + int bit; > > + for (bit = 0; bit < 32; bit++) { > > + if (!fi->feat_names[bit]) { > > + continue; > > + } > > + qdict_put_obj(props, fi->feat_names[bit], > > + object_property_get_qobject(obj, fi->feat_names[bit], > > + errp)); > > + } > > + } > > + > > + for (pv = kvm_default_props; pv->prop; pv++) { > > + qdict_put_obj(props, pv->prop, > > + object_property_get_qobject(obj, pv->prop, errp)); > > + } > > + for (pv = tcg_default_props; pv->prop; pv++) { > > + qdict_put_obj(props, pv->prop, > > + object_property_get_qobject(obj, pv->prop, errp)); > > + } > > + > > + qdict_put_obj(props, "vendor", > > + object_property_get_qobject(obj, "vendor", errp)); > > + > > + /* Set by "host": */ > > + qdict_put_obj(props, "lmce", > > + object_property_get_qobject(obj, "lmce", errp)); > > + qdict_put_obj(props, "pmu", > > + object_property_get_qobject(obj, "pmu", errp)); > > + > > + > > + /* Other properties configurable by the user: */ > > + qdict_put_obj(props, "host-cache-info", > > + object_property_get_qobject(obj, "host-cache-info", errp)); > > +} > > + > > +static void object_apply_props(Object *obj, QDict *props, Error **errp) > > +{ > > + const QDictEntry *prop; > > + Error *err = NULL; > > + > > + for (prop = qdict_first(props); prop; prop = qdict_next(props, prop)) { > > + object_property_set_qobject(obj, qdict_entry_value(prop), > > + qdict_entry_key(prop), &err); > > + if (err) { > > + break; > > + } > > + } > > + > > + error_propagate(errp, err); > > +} > > + > > +static X86CPU *x86_cpu_from_model(CpuModelInfo *model, Error **errp) > > +{ > > + X86CPU *xc = NULL; > > + X86CPUClass *xcc; > > + Error *err = NULL; > > + > > + xcc = X86_CPU_CLASS(cpu_class_by_name(TYPE_X86_CPU, model->name)); > > + if (xcc == NULL) { > > + error_setg(&err, "CPU model '%s' not found", model->name); > > + goto out; > > + } > > + > > + xc = X86_CPU(object_new(object_class_get_name(OBJECT_CLASS(xcc)))); > > + if (model->has_props) { > > + QDict *d = qobject_to_qdict(model->props); > > + if (!d) { > > + error_setg(&err, "model.props must be a dictionary"); > > + goto out; > > How can this happen? 'props' is 'any' in the QAPI schema, because (it looks like) QAPI doesn't have a 'dict' type.

> > + } > > + object_apply_props(OBJECT(xc), d, &err); > > + if (err) { > > + goto out; > > + } > > + } > > + > > + x86_cpu_expand_features(xc, &err); > > + if (err) { > > + goto out; > > + } > > + > > +out: > > + if (err) { > > + error_propagate(errp, err); > > + object_unref(OBJECT(xc)); > > + xc = NULL; > > + } > > + return xc; > > +} > > + > > +CpuModelExpansionInfo *arch_query_cpu_model_expansion(CpuModelExpansionType type, > > + CpuModelInfo *model, > > + Error **errp) > > +{ > > + X86CPU *xc = NULL; > > + Error *err = NULL; > > + CpuModelExpansionInfo *ret = g_new0(CpuModelExpansionInfo, 1); > > + QDict *props; > > + > > + xc = x86_cpu_from_model(model, &err); > > + if (err) { > > + goto out; > > + } > > + > > + /* We currently always do full expansion */ > > This comment made me go "wait, we do full expansion even when @type is > CPU_MODEL_EXPANSION_TYPE_STATIC?" Looks like we first to full > expansion, then correct the result according to type. The comment is a leftover from a previous version where we didn't even check expansion type. I will remove it (or clarify it). > > > + ret->model = g_new0(CpuModelInfo, 1); > > + ret->model->name = g_strdup("base"); /* the only static model */ > > + props = qdict_new(); > > + ret->model->props = QOBJECT(props); > > + ret->model->has_props = true; > > + x86_cpu_to_dict(xc, props, &err); > > + > > + /* Some features (pmu, host-cache-info) are not migration-safe, > > + * and are handled differently depending on expansion type: > > + */ > > + if (type == CPU_MODEL_EXPANSION_TYPE_STATIC) { > > Single space after ==, please. Will fix. > > > + /* static expansion force migration-unsafe features off: */ > > + ret->q_static = ret->migration_safe = true; > > + qdict_del(props, "pmu"); > > + qdict_del(props, "host-cache-info"); > > + } else if (type == CPU_MODEL_EXPANSION_TYPE_FULL) { > > + QObject *o; > > + /* full expansion clear the static/migration-safe flags > > + * to indicate migration-unsafe features are on: > > + */ > > + ret->q_static = true; > > + ret->migration_safe = true; > > + > > + o = qdict_get(props, "pmu"); > > + if (o && qbool_get_bool(qobject_to_qbool(o))) { > > + ret->q_static = ret->migration_safe = false; > > + } > > + o = qdict_get(props, "host-cache-info"); > > + if (o && qbool_get_bool(qobject_to_qbool(o))) { > > + ret->q_static = ret->migration_safe = false; > > + } > > + } else { > > + error_setg(&err, "The requested expansion type is not supported."); > > How can this happen? > > If it can, it bombs when x86_cpu_to_dict() already set an error (see > "use of the error API" above). This can happen if we change the QAPI schema to support another expansion type in the future.

> > > + } > > + > > +out: > > + object_unref(OBJECT(xc)); > > + if (err) { > > + error_propagate(errp, err); > > + qapi_free_CpuModelExpansionInfo(ret); > > + ret = NULL; > > + } > > + return ret; > > +} > > + > > X86CPU *cpu_x86_init(const char *cpu_model) > > { > > return X86_CPU(cpu_generic_init(TYPE_X86_CPU, cpu_model));