On 13.01.21 01:57, David Gibson wrote:
> On Tue, Jan 12, 2021 at 12:36:07PM +0100, Cornelia Huck wrote:
> 65;6201;1c> On Tue, 12 Jan 2021 09:15:26 +0100
>> Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote:
>>
>>> On 12.01.21 05:45, David Gibson wrote:
>>>> At least some s390 cpu models support "Protected Virtualization" (PV),
>>>> a mechanism to protect guests from eavesdropping by a compromised
>>>> hypervisor.
>>>>
>>>> This is similar in function to other mechanisms like AMD's SEV and
>>>> POWER's PEF, which are controlled by the "confidential-guest-support"
>>>> machine option. s390 is a slightly special case, because we already
>>>> supported PV, simply by using a CPU model with the required feature
>>>> (S390_FEAT_UNPACK).
>>>>
>>>> To integrate this with the option used by other platforms, we
>>>> implement the following compromise:
>>>>
>>>> - When the confidential-guest-support option is set, s390 will
>>>> recognize it, verify that the CPU can support PV (failing if not)
>>>> and set virtio default options necessary for encrypted or protected
>>>> guests, as on other platforms. i.e. if confidential-guest-support
>>>> is set, we will either create a guest capable of entering PV mode,
>>>> or fail outright.
>>>>
>>>> - If confidential-guest-support is not set, guests might still be
>>>> able to enter PV mode, if the CPU has the right model. This may be
>>>> a little surprising, but shouldn't actually be harmful.
>>>>
>>>> To start a guest supporting Protected Virtualization using the new
>>>> option use the command line arguments:
>>>> -object s390-pv-guest,id=pv0 -machine confidential-guest-support=pv0
>>>
>>>
>>> This results in
>>>
>>> [cborntra@t35lp61 qemu]$ qemu-system-s390x -enable-kvm -nographic -m 2G -kernel ~/full.normal
>>> **
>>> ERROR:../qom/object.c:317:type_initialize: assertion failed: (parent->instance_size <= ti->instance_size)
>>> Bail out! ERROR:../qom/object.c:317:type_initialize: assertion failed: (parent->instance_size <= ti->instance_size)
>>> Aborted (core dumped)
>>>
>>
>>>> +static const TypeInfo s390_pv_guest_info = {
>>>> + .parent = TYPE_CONFIDENTIAL_GUEST_SUPPORT,
>>>> + .name = TYPE_S390_PV_GUEST,
>>>> + .instance_size = sizeof(S390PVGuestState),
>>>> + .interfaces = (InterfaceInfo[]) {
>>>> + { TYPE_USER_CREATABLE },
>>>> + { }
>>>> + }
>>>> +};
>>
>> I think this needs TYPE_OBJECT in .parent and
>> TYPE_CONFIDENTIAL_GUEST_SUPPORT as an interface to fix the crash.
>
> No, that was true of an earlier revision, but parent is correct in the
> current version.
right now parent is obviously wrong as it triggers the above warning (and all other
variants in the previous patches also use TYPE_OBJECT). It is probably the right
thing when you fix
+struct S390PVGuestState {
+ Object parent_obj;
+};
+
and change Object to the proper type I guess.
