From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56474) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dB1s0-0000hT-DK for qemu-devel@nongnu.org; Wed, 17 May 2017 12:32:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dB1rw-0000md-Gw for qemu-devel@nongnu.org; Wed, 17 May 2017 12:32:16 -0400 Received: from hall.aurel32.net ([2001:bc8:30d7:100::1]:51688) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dB1rw-0000lY-AG for qemu-devel@nongnu.org; Wed, 17 May 2017 12:32:12 -0400 Date: Wed, 17 May 2017 18:26:42 +0200 From: Aurelien Jarno Message-ID: <20170517162642.ebmrhawmfdde5vsz@aurel32.net> References: <1495035337-13337-1-git-send-email-thuth@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1495035337-13337-1-git-send-email-thuth@redhat.com> Subject: Re: [Qemu-devel] [RFC PATCH] target/s390x/cpu_models: Set some additional feature bits for the "qemu" CPU List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth Cc: qemu-devel@nongnu.org, Richard Henderson , Alexander Graf , David Hildenbrand , mmarek@suse.com, mbenes@suse.cz On 2017-05-17 17:35, Thomas Huth wrote: > 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, we should present > as much of the supported features as possible when we are running > with the default "qemu" CPU. > This patch now adds the "stfle", "extended immediate" and "stckf" > facility bits to the "qemu" CPU, which are already supported facilities. > It is unfortunately still not enough to run e.g. recent Fedora kernels, > but at least it's a first step into the right direction. This indeed looks like a step in a good direction. At least it makes the recently added STFLE emulation useful :-). > Signed-off-by: Thomas Huth > --- > target/s390x/cpu_models.c | 29 ++++++++++++++++++++++++++--- > 1 file changed, 26 insertions(+), 3 deletions(-) > > diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c > index 8d27363..18789ab 100644 > --- a/target/s390x/cpu_models.c > +++ b/target/s390x/cpu_models.c > @@ -658,6 +658,24 @@ 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) > +{ > + int i, feats[] = { > + S390_FEAT_STFLE, > + S390_FEAT_EXTENDED_IMMEDIATE, > + S390_FEAT_STORE_CLOCK_FAST According to my list, QEMU also fully implements the following facilities: S390_FEAT_LONG_DISPLACEMENT S390_FEAT_GENERAL_INSTRUCTIONS_EXT S390_FEAT_EXECUTE_EXT S390_FEAT_STFLE_45 > + }; > + > + 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 +688,11 @@ 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 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 +944,15 @@ 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 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.default_feat); > + 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); > } Otherwise it looks fine to me. Reviewed-by: Aurelien Jarno -- Aurelien Jarno GPG: 4096R/1DDD8C9B aurelien@aurel32.net http://www.aurel32.net