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Re: [Qemu-devel] [RFC PATCH] target/s390x/cpu_models: Set some additiona
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [RFC PATCH] target/s390x/cpu_models: Set some additional feature bits for the "qemu" CPU |
Date: |
Wed, 17 May 2017 18:26:42 +0200 |
User-agent: |
NeoMutt/20170113 (1.7.2) |
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 <address@hidden>
> ---
> 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 <address@hidden>
--
Aurelien Jarno GPG: 4096R/1DDD8C9B
address@hidden http://www.aurel32.net
- [Qemu-devel] [RFC PATCH] target/s390x/cpu_models: Set some additional feature bits for the "qemu" CPU, Thomas Huth, 2017/05/17
- Re: [Qemu-devel] [RFC PATCH] target/s390x/cpu_models: Set some additional feature bits for the "qemu" CPU,
Aurelien Jarno <=
- Re: [Qemu-devel] [RFC PATCH] target/s390x/cpu_models: Set some additional feature bits for the "qemu" CPU, David Hildenbrand, 2017/05/17
- Re: [Qemu-devel] [RFC PATCH] target/s390x/cpu_models: Set some additional feature bits for the "qemu" CPU, Thomas Huth, 2017/05/17
- Re: [Qemu-devel] [RFC PATCH] target/s390x/cpu_models: Set some additional feature bits for the "qemu" CPU, Aurelien Jarno, 2017/05/18
- Re: [Qemu-devel] [RFC PATCH] target/s390x/cpu_models: Set some additional feature bits for the "qemu" CPU, David Hildenbrand, 2017/05/18
- Re: [Qemu-devel] [RFC PATCH] target/s390x/cpu_models: Set some additional feature bits for the "qemu" CPU, Christian Borntraeger, 2017/05/18
- Re: [Qemu-devel] [RFC PATCH] target/s390x/cpu_models: Set some additional feature bits for the "qemu" CPU, Thomas Huth, 2017/05/18
- Re: [Qemu-devel] [RFC PATCH] target/s390x/cpu_models: Set some additional feature bits for the "qemu" CPU, David Hildenbrand, 2017/05/18
- Re: [Qemu-devel] [RFC PATCH] target/s390x/cpu_models: Set some additional feature bits for the "qemu" CPU, Thomas Huth, 2017/05/18