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. Thanks a lot for the testing, Matthew! Thomas
