On 20.01.20 10:49, Thomas Huth wrote: > The AIS feature has been disabled late in the v2.10 development cycle since > there were some issues with migration (see commit 3f2d07b3b01ea61126b - > "s390x/ais: for 2.10 stable: disable ais facility"). We originally wanted > to enable it again for newer machine types, but apparently we forgot to do > this so far. Let's do it for the new s390-ccw-virtio-5.0 machine now. > > While at it, also add a more verbose comment why we need the *_allowed() > wrappers in s390-virtio-ccw.c. > > Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1756946 > Signed-off-by: Thomas Huth <th...@redhat.com> > --- > Matthew, could you please give this another try on your system? Thanks! > > hw/s390x/s390-virtio-ccw.c | 20 +++++++++++++++++--- > include/hw/s390x/s390-virtio-ccw.h | 3 +++ > target/s390x/kvm.c | 9 ++++++--- > 3 files changed, 26 insertions(+), 6 deletions(-) > > diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c > index e0e28139a2..4de6c340aa 100644 > --- a/hw/s390x/s390-virtio-ccw.c > +++ b/hw/s390x/s390-virtio-ccw.c > @@ -452,6 +452,7 @@ static void ccw_machine_class_init(ObjectClass *oc, void > *data) > s390mc->cpu_model_allowed = true; > s390mc->css_migration_enabled = true; > s390mc->hpage_1m_allowed = true; > + s390mc->kvm_ais_allowed = true; > mc->init = ccw_init; > mc->reset = s390_machine_reset; > mc->hot_add_cpu = s390_hot_add_cpu; > @@ -505,6 +506,14 @@ static inline void machine_set_dea_key_wrap(Object *obj, > bool value, > > static S390CcwMachineClass *current_mc; > > +/* > + * Get the class of the s390-ccw-virtio machine that is currently in use. > + * Note: libvirt is using the "none" machine to probe for the features of the > + * host CPU, so in case this is called with the "none" machine, the function > + * returns the TYPE_S390_CCW_MACHINE base class. In this base class, all the > + * various "*_allowed" variables are enabled, so that the *_allowed() > wrappers > + * below return the correct default value for the "none" machine. > + */ > static S390CcwMachineClass *get_machine_class(void) > { > if (unlikely(!current_mc)) { > @@ -521,22 +530,24 @@ static S390CcwMachineClass *get_machine_class(void) > > bool ri_allowed(void) > { > - /* for "none" machine this results in true */ > return get_machine_class()->ri_allowed; > } > > bool cpu_model_allowed(void) > { > - /* for "none" machine this results in true */ > return get_machine_class()->cpu_model_allowed; > } > > bool hpage_1m_allowed(void) > { > - /* for "none" machine this results in true */ > return get_machine_class()->hpage_1m_allowed; > } > > +bool kvm_ais_allowed(void) > +{ > + return get_machine_class()->kvm_ais_allowed; > +} > + > static char *machine_get_loadparm(Object *obj, Error **errp) > { > S390CcwMachineState *ms = S390_CCW_MACHINE(obj); > @@ -658,6 +669,9 @@ static void ccw_machine_4_2_instance_options(MachineState > *machine) > > static void ccw_machine_4_2_class_options(MachineClass *mc) > { > + S390CcwMachineClass *s390mc = S390_MACHINE_CLASS(mc); > + > + s390mc->kvm_ais_allowed = false; > ccw_machine_5_0_class_options(mc); > compat_props_add(mc->compat_props, hw_compat_4_2, hw_compat_4_2_len); > } > diff --git a/include/hw/s390x/s390-virtio-ccw.h > b/include/hw/s390x/s390-virtio-ccw.h > index 8aa27199c9..e3ba3b88b1 100644 > --- a/include/hw/s390x/s390-virtio-ccw.h > +++ b/include/hw/s390x/s390-virtio-ccw.h > @@ -40,6 +40,7 @@ typedef struct S390CcwMachineClass { > bool cpu_model_allowed; > bool css_migration_enabled; > bool hpage_1m_allowed; > + bool kvm_ais_allowed; > } S390CcwMachineClass; > > /* runtime-instrumentation allowed by the machine */ > @@ -48,6 +49,8 @@ bool ri_allowed(void); > bool cpu_model_allowed(void); > /* 1M huge page mappings allowed by the machine */ > bool hpage_1m_allowed(void); > +/* adapter-interrupt suppression allowed by the machine? */ > +bool kvm_ais_allowed(void); > > /** > * Returns true if (vmstate based) migration of the channel subsystem > diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c > index 15260aeb9a..cf4fb4f2d9 100644 > --- a/target/s390x/kvm.c > +++ b/target/s390x/kvm.c > @@ -365,10 +365,13 @@ int kvm_arch_init(MachineState *ms, KVMState *s) > /* > * The migration interface for ais was introduced with kernel 4.13 > * but the capability itself had been active since 4.12. As migration > - * support is considered necessary let's disable ais in the 2.10 > - * machine. > + * support is considered necessary, we only try to enable this for > + * newer machine types if KVM_CAP_S390_AIS_MIGRATION is available. > */ > - /* kvm_vm_enable_cap(s, KVM_CAP_S390_AIS, 0); */ > + if (kvm_ais_allowed() && > + kvm_check_extension(s, KVM_CAP_S390_AIS_MIGRATION)) { > + kvm_vm_enable_cap(s, KVM_CAP_S390_AIS, 0); > + } > > kvm_set_max_memslot_size(KVM_SLOT_MAX_BYTES); > return 0; >
Reviewed-by: David Hildenbrand <da...@redhat.com> -- Thanks, David / dhildenb
