On 17/01/2020 12.05, Christian Borntraeger wrote: > > > On 17.01.20 11:38, Thomas Huth wrote: >> On 16/01/2020 21.26, Cornelia Huck wrote: >>> On Thu, 16 Jan 2020 15:19:13 -0500 >>> Matthew Rosato <mjros...@linux.ibm.com> wrote: >>> >>>> On 1/16/20 7:20 AM, 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. >>>>> >>>>> 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(-) >>> >>> (...) >>> >>>>> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c >>>>> index 15260aeb9a..4c1c8c0208 100644 >>>>> --- a/target/s390x/kvm.c >>>>> +++ b/target/s390x/kvm.c >>>>> @@ -329,6 +329,8 @@ static void ccw_machine_class_foreach(ObjectClass >>>>> *oc, void *opaque) >>>>> >>>>> int kvm_arch_init(MachineState *ms, KVMState *s) >>>>> { >>>>> + S390CcwMachineClass *smc = S390_CCW_MACHINE_OBJ_GET_CLASS(ms); >>>>> + >>>> >>>> I still can't run a proper test due to unavailable hw but in the >>>> meantime I tried to virsh define a libvirt guest pointed at qemu (master >>>> + this patch). Regardless of machine type (s390-ccw-virtio-5.0 or >>>> s390-ccw-virtio-4.2) I get: >>>> >>>> virsh define guest.xml >>>> error: Failed to define domain from /path/to/guest.xml >>>> error: invalid argument: could not find capabilities for arch=s390x >>>> domaintype=kvm >>>> >>>> Similarly: >>>> >>>> virsh domcapabilities >>>> error: failed to get emulator capabilities >>>> error: invalid argument: unable to find any emulator to serve 's390x' >>>> architecture >>>> >>>> Rolling back to qemu master, the define and domcapabilities work (with >>>> no ais of course). >>>> >>>> So: there is some incompatibility between the way libvirt invokes qemu >>>> to detect capabilities and this code. The above line seems to be the >>>> root problem - if I take your patch and remove 'smc' then libvirt works >>>> as expected and I can see ais in the domcapabilities. >>>> >>>> Looking at those wrappers David mentioned... I suspect you need this >>>> for the 'none' machine case. I tried a quick hack with the following: >>>> >>>> bool ais_allowed(void) >>>> { >>>> /* for "none" machine this results in true */ >>>> return get_machine_class()->kvm_ais_allowed; >>>> } >>>> >>>> and >>>> >>>> if (ais_allowed() && >>>> kvm_check_extension(s, KVM_CAP_S390_AIS_MIGRATION)) { >>>> kvm_vm_enable_cap(s, KVM_CAP_S390_AIS, 0); >>>> } >>>> >>>> This works and doesn't break libvirt compatibility detection. >>> >>> Oh, "none" machine fun again... I think you're on the right track, and >>> we really need a wrapper. >> >> D'oh, so this is the real reason for the wrappers ... ok, I'll respin my >> patch accordingly. > > > Can you add a comment to the wrappers?
Yes, good idea, I'll do that! Thomas
