cpuid: Ignore known (and harmless) KVM CPUID change

Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>

qemu/tests/cfg/qemu_cpu.cfg

@@ -251,6 +251,14 @@
                         ignore_cpuid_leaves += " 0,0,ebx 0,0,ecx 0,0,edx"
                         ignore_cpuid_leaves += " 0x80000000,0,ebx 0x80000000,0,ecx 0x80000000,0,edx"
 
+                    #KNOWN BUG: QEMU 2.1.0 broke the ABI by changing
+                    # CPUID[0x40000000].EAX without any compat code
+                    kvm:
+                        pc_1_0, pc_1_1, pc_1_2, pc_1_3, pc_q35_1_4, pc_i440fx_1_4, pc_q35_1_5, pc_i440fx_1_5:
+                            # Ignore only bits 30 and 0. that means 0x400000001 and 0 are equivalent, but
+                            # other bits can't change
+                            ignore_cpuid_leaves += " 0x40000000,0,eax,0 0x40000000,0,eax,30"
+
                     #KNOWN BUG: Processor Extended State leaf depends on host,
                     # currently:
                     ignore_cpuid_leaves += " 0xd,0"