Starting a KVM domain on s390 with old machine type (such as
s390-ccw-virtio-2.5) and without any guest CPU model configured fails
with
CPU models are not available: KVM doesn't support CPU models
QEMU error. This is cause by libvirt using host-model CPU as the default
CPU based on QEMU reporting "host" CPU model as being the default one
(see commit v5.9.0-402-g24d8202294: qemu: Use host-model CPU on s390 by
default). However, even though both QEMU and KVM support CPU models on
s390 and QEMU can give us the host-model CPU, we can't use it with old
machine types which only support -cpu host.
https://bugzilla.redhat.com/show_bug.cgi?id=1795651
Reported-by: Christian Ehrhardt <paelzer@xxxxxxxxx>
Signed-off-by: Jiri Denemark <jdenemar@xxxxxxxxxx>
---
src/qemu/qemu_capabilities.c | 19 ++++++++++++++++++-
...t-cpu-kvm-ccw-virtio-2.7.s390x-latest.args | 4 +---
...lt-cpu-kvm-ccw-virtio-2.7.s390x-latest.xml | 2 +-
3 files changed, 20 insertions(+), 5 deletions(-)
diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index 162e49e2d4..dd2311cfa9 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -2274,16 +2274,33 @@ virQEMUCapsIsVirtTypeSupported(virQEMUCapsPtr qemuCaps,
return false;
}
+const char *s390HostPassthroughOnlyMachines[] = {
+ "s390-ccw-virtio-2.4",
+ "s390-ccw-virtio-2.5",
+ "s390-ccw-virtio-2.6",
+ "s390-ccw-virtio-2.7",
+ NULL
+};
bool
virQEMUCapsIsCPUModeSupported(virQEMUCapsPtr qemuCaps,
virArch hostarch,
virDomainVirtType type,
virCPUMode mode,
- const char *machineType G_GNUC_UNUSED)
+ const char *machineType)
{
qemuMonitorCPUDefsPtr cpus;
+ /* CPU models (except for "host") are not supported by QEMU for on s390
+ * KVM domains with old machine types regardless on QEMU version. */
+ if (ARCH_IS_S390(qemuCaps->arch) &&
+ type == VIR_DOMAIN_VIRT_KVM &&
+ mode != VIR_CPU_MODE_HOST_PASSTHROUGH &&
+ machineType &&
+ g_strv_contains(s390HostPassthroughOnlyMachines, machineType)) {
+ return false;
+ }
+
switch (mode) {
case VIR_CPU_MODE_HOST_PASSTHROUGH:
return type == VIR_DOMAIN_VIRT_KVM &&
diff --git a/tests/qemuxml2argvdata/s390-default-cpu-kvm-ccw-virtio-2.7.s390x-latest.args b/tests/qemuxml2argvdata/s390-default-cpu-kvm-ccw-virtio-2.7.s390x-latest.args
index 8c25a01e74..0c2567df6c 100644
--- a/tests/qemuxml2argvdata/s390-default-cpu-kvm-ccw-virtio-2.7.s390x-latest.args
+++ b/tests/qemuxml2argvdata/s390-default-cpu-kvm-ccw-virtio-2.7.s390x-latest.args
@@ -13,9 +13,7 @@ QEMU_AUDIO_DRV=none \
-object secret,id=masterKey0,format=raw,\
file=/tmp/lib/domain--1-test/master-key.aes \
-machine s390-ccw-virtio-2.7,accel=kvm,usb=off,dump-guest-core=off \
--cpu z13.2-base,aen=on,aefsi=on,msa5=on,msa4=on,msa3=on,msa2=on,msa1=on,\
-sthyi=on,edat=on,ri=on,edat2=on,vx=on,ipter=on,ap=on,esop=on,apft=on,apqci=on,\
-cte=on,bpb=on,ppa15=on,zpci=on,sea_esop2=on,te=on,cmm=on \
+-cpu host \
-m 256 \
-overcommit mem-lock=off \
-smp 1,sockets=1,cores=1,threads=1 \
diff --git a/tests/qemuxml2xmloutdata/s390-default-cpu-kvm-ccw-virtio-2.7.s390x-latest.xml b/tests/qemuxml2xmloutdata/s390-default-cpu-kvm-ccw-virtio-2.7.s390x-latest.xml
index 56fd22b6e5..8799584c11 100644
--- a/tests/qemuxml2xmloutdata/s390-default-cpu-kvm-ccw-virtio-2.7.s390x-latest.xml
+++ b/tests/qemuxml2xmloutdata/s390-default-cpu-kvm-ccw-virtio-2.7.s390x-latest.xml
@@ -8,7 +8,7 @@
<type arch='s390x' machine='s390-ccw-virtio-2.7'>hvm</type>
<boot dev='hd'/>
</os>
- <cpu mode='host-model' check='partial'/>
+ <cpu mode='host-passthrough' check='none'/>
<clock offset='utc'/>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
--
2.25.0
