[Qemu-devel] [Patch v4 22/30] s390x/kvm: disable host model for problematic compat machines

[David Hildenbrand]

Compatibility machines that touch runtime-instrumentation should not
be used with the CPU model. Otherwise the host model will look different,
depending on the QEMU machine QEMU has been started with.

So let's simply disable the host model for existing compatibility machines
that all disable ri. This, in return, disables the CPU model for these
compat machines completely.

Acked-by: Cornelia Huck <address@hidden>
Signed-off-by: David Hildenbrand <address@hidden>
---
 target-s390x/kvm.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index 2cc0357..3c0929b 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -2451,6 +2451,10 @@ static int configure_cpu_feat(const S390FeatBitmap 
features)
 
 bool kvm_s390_cpu_models_supported(void)
 {
+    if (!ri_allowed()) {
+        /* compatibility machines interfere with the cpu model */
+        return false;
+    }
     return kvm_vm_check_attr(kvm_state, KVM_S390_VM_CPU_MODEL,
                              KVM_S390_VM_CPU_MACHINE) &&
            kvm_vm_check_attr(kvm_state, KVM_S390_VM_CPU_MODEL,
-- 
2.8.4