From fc7fbcbc4829563469fa33b68e6b771d455229ac Mon Sep 17 00:00:00 2001 From: Thomas Huth Date: Thu, 25 May 2017 11:22:12 +0200 Subject: [PATCH] target/s390x/cpu_models: Allow some additional feature bits for the "qemu" CPU Currently we only present the plain z900 feature bits to the guest, but QEMU already emulates some additional features (but not all of the next CPU generation, so we can not use the next CPU level as default yet). Since newer Linux kernels are checking the feature bits and refuse to work if a required feature is missing, it would be nice to have a way to present more of the supported features when we are running with the "qemu" CPU. This patch now adds the supported features to the "full_feat" bitmap, so that additional features can be enabled on the command line now, for example with: qemu-system-s390x -cpu qemu,stfle=true,ldisp=true,eimm=true,stckf=true Acked-by: David Hildenbrand Reviewed-by: Aurelien Jarno Signed-off-by: Thomas Huth Message-Id: <1495704132-5675-1-git-send-email-thuth@redhat.com> Signed-off-by: Richard Henderson --- target/s390x/cpu_models.c | 34 +++++++++++++++++++++++++++++++--- 1 file changed, 31 insertions(+), 3 deletions(-) diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c index 8d27363b07..e5e005a430 100644 --- a/target/s390x/cpu_models.c +++ b/target/s390x/cpu_models.c @@ -658,6 +658,30 @@ static void check_compatibility(const S390CPUModel *max_model, "available in the configuration: "); } +/** + * The base TCG CPU model "qemu" is based on the z900. However, we already + * can also emulate some additional features of later CPU generations, so + * we add these additional feature bits here. + */ +static void add_qemu_cpu_model_features(S390FeatBitmap fbm) +{ + static const int feats[] = { + S390_FEAT_STFLE, + S390_FEAT_EXTENDED_IMMEDIATE, + S390_FEAT_LONG_DISPLACEMENT, + S390_FEAT_LONG_DISPLACEMENT_FAST, + S390_FEAT_STORE_CLOCK_FAST, + S390_FEAT_GENERAL_INSTRUCTIONS_EXT, + S390_FEAT_EXECUTE_EXT, + S390_FEAT_STFLE_45, + }; + int i; + + for (i = 0; i < ARRAY_SIZE(feats); i++) { + set_bit(feats[i], fbm); + } +} + static S390CPUModel *get_max_cpu_model(Error **errp) { static S390CPUModel max_model; @@ -670,10 +694,11 @@ static S390CPUModel *get_max_cpu_model(Error **errp) if (kvm_enabled()) { kvm_s390_get_host_cpu_model(&max_model, errp); } else { - /* TCG emulates a z900 */ + /* TCG emulates a z900 (with some optional additional features) */ max_model.def = &s390_cpu_defs[0]; bitmap_copy(max_model.features, max_model.def->default_feat, S390_FEAT_MAX); + add_qemu_cpu_model_features(max_model.features); } if (!*errp) { cached = true; @@ -925,11 +950,14 @@ static void s390_host_cpu_model_initfn(Object *obj) static void s390_qemu_cpu_model_initfn(Object *obj) { + static S390CPUDef s390_qemu_cpu_defs; S390CPU *cpu = S390_CPU(obj); cpu->model = g_malloc0(sizeof(*cpu->model)); - /* TCG emulates a z900 */ - cpu->model->def = &s390_cpu_defs[0]; + /* TCG emulates a z900 (with some optional additional features) */ + memcpy(&s390_qemu_cpu_defs, &s390_cpu_defs[0], sizeof(s390_qemu_cpu_defs)); + add_qemu_cpu_model_features(s390_qemu_cpu_defs.full_feat); + cpu->model->def = &s390_qemu_cpu_defs; bitmap_copy(cpu->model->features, cpu->model->def->default_feat, S390_FEAT_MAX); }