s390x/sclp: propagate the ibc val (lowest and unblocked ibc)

If we have a lowest ibc, we can indicate the ibc to the guest.
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Message-Id: <20160905085244.99980-17-dahi@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

hw/s390x/sclp.c

@@ -67,6 +67,8 @@ static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb)
     read_info->offset_cpu = cpu_to_be16(offsetof(ReadInfo, entries));
     read_info->highest_cpu = cpu_to_be16(max_cpus);
 
+    read_info->ibc_val = cpu_to_be32(s390_get_ibc_val());
+
     /* Configuration Characteristic (Extension) */
     s390_get_feat_block(S390_FEAT_TYPE_SCLP_CONF_CHAR,
                          read_info->conf_char);

include/hw/s390x/sclp.h

@@ -121,7 +121,8 @@ typedef struct ReadInfo {
     uint8_t  loadparm[8];               /* 24-31 */
     uint8_t  _reserved3[48 - 32];       /* 32-47 */
     uint64_t facilities;                /* 48-55 */
-    uint8_t  _reserved0[80 - 56];       /* 56-79 */
+    uint8_t  _reserved0[76 - 56];       /* 56-75 */
+    uint32_t ibc_val;
     uint8_t  conf_char[96 - 80];        /* 80-95 */
     uint8_t  _reserved4[100 - 96];      /* 96-99 */
     uint32_t rnsize2;

target-s390x/cpu_models.c

@@ -74,6 +74,27 @@ static S390CPUDef s390_cpu_defs[] = {
     CPUDEF_INIT(0x2965, 13, 2, 47, 0x08000000U, "z13s", "IBM z13s GA1"),
 };
 
+uint32_t s390_get_ibc_val(void)
+{
+    uint16_t unblocked_ibc, lowest_ibc;
+    static S390CPU *cpu;
+
+    if (!cpu) {
+        cpu = S390_CPU(qemu_get_cpu(0));
+    }
+
+    if (!cpu || !cpu->model) {
+        return 0;
+    }
+    unblocked_ibc = s390_ibc_from_cpu_model(cpu->model);
+    lowest_ibc = cpu->model->lowest_ibc;
+    /* the lowest_ibc always has to be <= unblocked_ibc */
+    if (!lowest_ibc || lowest_ibc > unblocked_ibc) {
+        return 0;
+    }
+    return ((uint32_t) lowest_ibc << 16) | unblocked_ibc;
+}
+
 void s390_get_feat_block(S390FeatType type, uint8_t *data)
 {
     static S390CPU *cpu;

target-s390x/cpu_models.h

@@ -49,6 +49,18 @@ typedef struct S390CPUModel {
     uint8_t cpu_ver;        /* CPU version, usually "ff" for kvm */
 } S390CPUModel;
 
+#define S390_GEN_Z10 0xa
+
+uint32_t s390_get_ibc_val(void);
+static inline uint16_t s390_ibc_from_cpu_model(const S390CPUModel *model)
+{
+    uint16_t ibc = 0;
+
+    if (model->def->gen >= S390_GEN_Z10) {
+        ibc = ((model->def->gen - S390_GEN_Z10) << 4) + model->def->ec_ga;
+    }
+    return ibc;
+}
 void s390_get_feat_block(S390FeatType type, uint8_t *data);
 bool s390_has_feat(S390Feat feat);