On 17.05.2017 18:26, Aurelien Jarno wrote: > 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 <th...@redhat.com> >> --- >> 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 >
If S390_FEAT_LONG_DISPLACEMENT is supported, so is S390_FEAT_LONG_DISPLACEMENT_FAST (because TCG obvious has high performance ;) ) -- Thanks, David