On Thu, 16 Jan 2020 13:20:26 +0100 Thomas Huth <th...@redhat.com> 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. > > Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1756946 > Signed-off-by: Thomas Huth <th...@redhat.com> > --- > hw/s390x/s390-virtio-ccw.c | 4 ++++ > include/hw/s390x/s390-virtio-ccw.h | 4 ++++ > target/s390x/kvm.c | 11 ++++++++--- > 3 files changed, 16 insertions(+), 3 deletions(-) > > @@ -365,10 +367,13 @@ 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 enable this for newer s/necessary we only enable this/necessary, we only try to enable this/ > + * machine types and if KVM_CAP_S390_AIS_MIGRATION is available. maybe s/and if/if/ > */ > - /* kvm_vm_enable_cap(s, KVM_CAP_S390_AIS, 0); */ > + if (smc->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; Looks good. Remind me again: ais only made a difference for pci devices, right? Is it enough to give this a quick whirl with virtio-pci devices?