Add support for the query-cpu-model-expansion QMP command to Arm. We do this selectively, only exposing CPU properties which represent optional CPU features which the user may want to enable/disable. Also, for simplicity, we restrict the list of queryable cpu models to 'max', 'host', or the current type when KVM is in use, even though there may exist KVM hosts where other types would also work. For example on a seattle you could use 'host' for the current type, but then attempt to query 'cortex-a57', which is also a valid CPU type to use with KVM on seattle hosts, but that query will fail with our simplifications. This shouldn't be an issue though as management layers and users have been preferring the 'host' CPU type for use with KVM for quite some time. Additionally, if the KVM-enabled QEMU instance running on a seattle host is using the cortex-a57 CPU type, then querying 'cortex-a57' will work. Finally, we only implement expansion type 'full', as Arm does not yet have a "base" CPU type. Below are some example calls and results (to save character clutter they're not in json, but are still json-ish to give the idea)
# expand the 'max' CPU model query-cpu-model-expansion: type:full, model:{ name:max } return: model:{ name:max, props:{ 'aarch64': true, 'pmu': true }} # attempt to expand the 'max' CPU model with pmu=off query-cpu-model-expansion: type:full, model:{ name:max, props:{ 'pmu': false }} return: model:{ name:max, props:{ 'aarch64': true, 'pmu': false }} # attempt to expand the 'max' CPU model with aarch64=off query-cpu-model-expansion: type:full, model:{ name:max, props:{ 'aarch64': false }} error: "'aarch64' feature cannot be disabled unless KVM is enabled and 32-bit EL1 is supported" In the last example KVM was not in use so an error was returned. Note1: It's possible for features to have dependencies on other features. I.e. it may be possible to change one feature at a time without error, but when attempting to change all features at once an error could occur depending on the order they are processed. It's also possible changing all at once doesn't generate an error, because a feature's dependencies are satisfied with other features, but the same feature cannot be changed independently without error. For these reasons callers should always attempt to make their desired changes all at once in order to ensure the collection is valid. Note2: Certainly more features may be added to the list of advertised features, e.g. 'vfp' and 'neon'. The only requirement is that their property set accessors fail when invalid configurations are detected. For vfp we would need something like set_vfp() { if (arm_feature(env, ARM_FEATURE_AARCH64) && cpu->has_vfp != cpu->has_neon) error("AArch64 CPUs must have both VFP and Neon or neither") in its set accessor, and the same for neon, rather than doing that check at realize time, which isn't executed at qmp query time. Signed-off-by: Andrew Jones <drjo...@redhat.com> --- qapi/target.json | 6 +- target/arm/monitor.c | 132 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 135 insertions(+), 3 deletions(-) diff --git a/qapi/target.json b/qapi/target.json index 1d4d54b6002e..edfa2f82b916 100644 --- a/qapi/target.json +++ b/qapi/target.json @@ -408,7 +408,7 @@ ## { 'struct': 'CpuModelExpansionInfo', 'data': { 'model': 'CpuModelInfo' }, - 'if': 'defined(TARGET_S390X) || defined(TARGET_I386)' } + 'if': 'defined(TARGET_S390X) || defined(TARGET_I386) || defined(TARGET_ARM)' } ## # @query-cpu-model-expansion: @@ -433,7 +433,7 @@ # query-cpu-model-expansion while using these is not advised. # # Some architectures may not support all expansion types. s390x supports -# "full" and "static". +# "full" and "static". Arm only supports "full". # # Returns: a CpuModelExpansionInfo. Returns an error if expanding CPU models is # not supported, if the model cannot be expanded, if the model contains @@ -447,7 +447,7 @@ 'data': { 'type': 'CpuModelExpansionType', 'model': 'CpuModelInfo' }, 'returns': 'CpuModelExpansionInfo', - 'if': 'defined(TARGET_S390X) || defined(TARGET_I386)' } + 'if': 'defined(TARGET_S390X) || defined(TARGET_I386) || defined(TARGET_ARM)' } ## # @CpuDefinitionInfo: diff --git a/target/arm/monitor.c b/target/arm/monitor.c index 41b32b94b258..19e3120eef95 100644 --- a/target/arm/monitor.c +++ b/target/arm/monitor.c @@ -23,7 +23,13 @@ #include "qemu/osdep.h" #include "hw/boards.h" #include "kvm_arm.h" +#include "qapi/error.h" +#include "qapi/visitor.h" +#include "qapi/qobject-input-visitor.h" #include "qapi/qapi-commands-target.h" +#include "qapi/qmp/qerror.h" +#include "qapi/qmp/qdict.h" +#include "qom/qom-qobject.h" static GICCapability *gic_cap_new(int version) { @@ -82,3 +88,129 @@ GICCapabilityList *qmp_query_gic_capabilities(Error **errp) return head; } + +static const char *cpu_model_advertised_features[] = { + "aarch64", "pmu", + NULL +}; + +CpuModelExpansionInfo *qmp_query_cpu_model_expansion(CpuModelExpansionType type, + CpuModelInfo *model, + Error **errp) +{ + CpuModelExpansionInfo *expansion_info; + const QDict *qdict_in = NULL; + QDict *qdict_out; + ObjectClass *oc; + Object *obj; + const char *name; + int i; + + if (type != CPU_MODEL_EXPANSION_TYPE_FULL) { + error_setg(errp, "The requested expansion type is not supported."); + return NULL; + } + + if (!kvm_enabled() && !strcmp(model->name, "host")) { + error_setg(errp, "The CPU definition '%s' requires KVM", model->name); + return NULL; + } + + oc = cpu_class_by_name(TYPE_ARM_CPU, model->name); + if (!oc) { + error_setg(errp, "The CPU definition '%s' is unknown.", model->name); + return NULL; + } + + if (kvm_enabled()) { + const char *cpu_type = current_machine->cpu_type; + int len = strlen(cpu_type) - strlen(ARM_CPU_TYPE_SUFFIX); + bool supported = false; + + if (!strcmp(model->name, "host") || !strcmp(model->name, "max")) { + /* These are kvmarm's recommended cpu types */ + supported = true; + } else if (strlen(model->name) == len && + !strncmp(model->name, cpu_type, len)) { + /* KVM is enabled and we're using this type, so it works. */ + supported = true; + } + if (!supported) { + error_setg(errp, "The CPU definition '%s' cannot " + "be used with KVM on this host", model->name); + return NULL; + } + } + + if (model->props) { + qdict_in = qobject_to(QDict, model->props); + if (!qdict_in) { + error_setg(errp, QERR_INVALID_PARAMETER_TYPE, "props", "dict"); + return NULL; + } + } + + obj = object_new(object_class_get_name(oc)); + + if (qdict_in) { + Visitor *visitor; + + visitor = qobject_input_visitor_new(model->props); + visit_start_struct(visitor, NULL, NULL, 0, errp); + if (*errp) { + object_unref(obj); + return NULL; + } + + i = 0; + while ((name = cpu_model_advertised_features[i++]) != NULL) { + if (qdict_get(qdict_in, name)) { + object_property_set(obj, visitor, name, errp); + if (*errp) { + break; + } + } + } + + if (!*errp) { + visit_check_struct(visitor, errp); + } + visit_end_struct(visitor, NULL); + visit_free(visitor); + if (*errp) { + object_unref(obj); + return NULL; + } + } + + expansion_info = g_new0(CpuModelExpansionInfo, 1); + expansion_info->model = g_malloc0(sizeof(*expansion_info->model)); + expansion_info->model->name = g_strdup(model->name); + + qdict_out = qdict_new(); + + i = 0; + while ((name = cpu_model_advertised_features[i++]) != NULL) { + ObjectProperty *prop = object_property_find(obj, name, NULL); + if (prop) { + QObject *value; + + assert(prop->get); + value = object_property_get_qobject(obj, name, errp); + assert(!*errp); + + qdict_put_obj(qdict_out, name, value); + } + } + + if (!qdict_size(qdict_out)) { + qobject_unref(qdict_out); + } else { + expansion_info->model->props = QOBJECT(qdict_out); + expansion_info->model->has_props = true; + } + + object_unref(obj); + + return expansion_info; +} -- 2.20.1