| Message ID | 20190418113110.160664-11-borntraeger@de.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | s390x: new guest features | expand |
On 18.04.19 13:31, Christian Borntraeger wrote: > While we have removed csske and bpb from the default model, the very > common case of "host-model" in libvirt (expanded to a base model > + features) would still contain bpb and csske. This can prevent > migration to a future machine for a host-model machine. Let us fence > bpb and csske when we run on a generation 15. If necessary the > user can still use -cpu 8561,csske=on,bpb=on to force enable these > features. > > Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> > --- > target/s390x/cpu_models.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c > index e727519686..03bdca1fb8 100644 > --- a/target/s390x/cpu_models.c > +++ b/target/s390x/cpu_models.c > @@ -629,6 +629,17 @@ CpuModelExpansionInfo *qmp_query_cpu_model_expansion(CpuModelExpansionType type, > return NULL; > } > > + /* > + * Do not claim CSSKE and BPB if the host model expands to > + * generation 15 or newer > + */ > + if (s390_model.def->gen >= 15) { > + clear_bit(S390_FEAT_CONDITIONAL_SSKE, > + (unsigned long *) &s390_model.features); > + clear_bit(S390_FEAT_BPB, > + (unsigned long *) &s390_model.features); > + } > + > if (type == CPU_MODEL_EXPANSION_TYPE_STATIC) { > delta_changes = true; > } else if (type != CPU_MODEL_EXPANSION_TYPE_FULL) { > The bad thing about it is, it hinders migration *to* this hw generation. Will have to think about this some more. As alternative, simply ignore S390_FEAT_CONDITIONAL_SSKE and S390_FEAT_BPB when baselining/comparing.
On 18.04.19 14:48, David Hildenbrand wrote: > On 18.04.19 13:31, Christian Borntraeger wrote: >> While we have removed csske and bpb from the default model, the very >> common case of "host-model" in libvirt (expanded to a base model >> + features) would still contain bpb and csske. This can prevent >> migration to a future machine for a host-model machine. Let us fence >> bpb and csske when we run on a generation 15. If necessary the >> user can still use -cpu 8561,csske=on,bpb=on to force enable these >> features. >> >> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> >> --- >> target/s390x/cpu_models.c | 11 +++++++++++ >> 1 file changed, 11 insertions(+) >> >> diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c >> index e727519686..03bdca1fb8 100644 >> --- a/target/s390x/cpu_models.c >> +++ b/target/s390x/cpu_models.c >> @@ -629,6 +629,17 @@ CpuModelExpansionInfo *qmp_query_cpu_model_expansion(CpuModelExpansionType type, >> return NULL; >> } >> >> + /* >> + * Do not claim CSSKE and BPB if the host model expands to >> + * generation 15 or newer >> + */ >> + if (s390_model.def->gen >= 15) { >> + clear_bit(S390_FEAT_CONDITIONAL_SSKE, >> + (unsigned long *) &s390_model.features); >> + clear_bit(S390_FEAT_BPB, >> + (unsigned long *) &s390_model.features); >> + } >> + >> if (type == CPU_MODEL_EXPANSION_TYPE_STATIC) { >> delta_changes = true; >> } else if (type != CPU_MODEL_EXPANSION_TYPE_FULL) { >> > > The bad thing about it is, it hinders migration *to* this hw generation. It does not, at least not with todays libvirt. It will happily ask for -cpu z14,bpb=on and the guest will have it. the current checking is done by starting a qemu with a "wished" model and then check for success. PS: I tested that with managedsave > Will have to think about this some more. As alternative, simply ignore > S390_FEAT_CONDITIONAL_SSKE and S390_FEAT_BPB when baselining/comparing.
diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c index e727519686..03bdca1fb8 100644 --- a/target/s390x/cpu_models.c +++ b/target/s390x/cpu_models.c @@ -629,6 +629,17 @@ CpuModelExpansionInfo *qmp_query_cpu_model_expansion(CpuModelExpansionType type, return NULL; } + /* + * Do not claim CSSKE and BPB if the host model expands to + * generation 15 or newer + */ + if (s390_model.def->gen >= 15) { + clear_bit(S390_FEAT_CONDITIONAL_SSKE, + (unsigned long *) &s390_model.features); + clear_bit(S390_FEAT_BPB, + (unsigned long *) &s390_model.features); + } + if (type == CPU_MODEL_EXPANSION_TYPE_STATIC) { delta_changes = true; } else if (type != CPU_MODEL_EXPANSION_TYPE_FULL) {
While we have removed csske and bpb from the default model, the very common case of "host-model" in libvirt (expanded to a base model + features) would still contain bpb and csske. This can prevent migration to a future machine for a host-model machine. Let us fence bpb and csske when we run on a generation 15. If necessary the user can still use -cpu 8561,csske=on,bpb=on to force enable these features. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> --- target/s390x/cpu_models.c | 11 +++++++++++ 1 file changed, 11 insertions(+)