On 03/26/2018 05:03 AM, Pierre Morel wrote:
On 26/03/2018 10:32, David Hildenbrand wrote:
On 16.03.2018 00:24, Tony Krowiak wrote:
If the CPU model indicates that AP facility is installed on
the guest (i.e., -cpu xxxx,ap=on), then the expectation is that
the AP bus running in the guest will initialize; however, if the
AP instructions are not being interpreted by the firmware, then
they will be intercepted and routed back to QEMU for handling.
If a handler is not defined to process the intercepted instruciton,
t
...snip...
+int ap_device_handle_nqap(S390CPU *cpu)
+{
+ CPUS390XState *env = &cpu->env;
+
+ if (s390_has_feat(S390_FEAT_AP)) {
+ env->regs[1] = 0x10000;
+
+ return 0;
+ }
+
+ return -EOPNOTSUPP;
+}
+
+int ap_device_handle_dqap(S390CPU *cpu)
+{
+ CPUS390XState *env = &cpu->env;
+
+ if (s390_has_feat(S390_FEAT_AP)) {
+ env->regs[1] = 0x10000;
+
+ return 0;
+ }
+
+ return -EOPNOTSUPP;
+}
+
+int ap_device_handle_pqap(S390CPU *cpu)
+{
+ CPUS390XState *env = &cpu->env;
+ int fc = 4 & (env->regs[0] >> 24);
+
+ /*
+ * The Query Configuration Information (QCI) function (fc
== 4) does not
+ * set a response code in reg 1, so check for that along
with the
+ * AP feature.
+ */
+ if ((fc != 4) && s390_has_feat(S390_FEAT_AP)) {
+ env->regs[1] = 0x10000;
+
+ return 0;
+ }
This would imply an operation exception in case fc==4, which
sounds very
wrong.
It depends but I think that the S390_FEAT_AP_QUERY_CONFIG_INFO
must be tested
to know what to answer.
If the feature is there, QCI must be answered correctly.
This is an interesting proposition which raises several issues that
will need to
be addressed. The only time the PQAP(QCI) instruction is
intercepted is when:
* A vfio-ap device is NOT defined for the guest because the vfio_ap
device driver
will set ECA.28 and the PQAP(QCI) instruction will be interpreted
* STFLE.12 is set for the guest
You say that the QCI must be answered correctly, but what is the
correct response?
If we return the matrix - i.e., APM, ADM and AQM - configured via
the mediated
matrix device's sysfs attributes files, then if any APQNs are
defined in the matrix,
we will have to handle *ALL* AP instructions by executing them on
behalf of the
guest. I suppose we could return an empty matrix in which case the
AP bus will come
up without any devices on the guest, but what is the expectation of
an admin who
deliberately configures the mediated matrix device? Should we
forego handling interception
of AP instructions and consider a guest configuration that turns on
S390_FEAT_AP but
does not define a vfio-ap device to be erroneous and terminate
starting of the guest?
Anybody have any thoughts?
there are also some error situations to handle in all three
functions.
To what error situations are you referring?