[PATCH v2 8/8] s390: guest support for diagnose 0x318

[Collin Walling]

DIAGNOSE 0x318 (diag 318) allows the storage of diagnostic data that
is collected by the firmware in the case of hardware/firmware service
events.

The instruction is invoked in the Linux kernel and is handled,
migrated, and reset (modified clear and load normal) by QEMU.
KVM assists with the get/set of the relevent data via IOCTLs.

This feature depends on the Extended-Length SCCB (els) feature. If
els is not present, then a warning will be printed and the SCLP bit
that allows the Linux kernel to execute the instruction will not be
set.

Availability of this instruction is determined by byte 134 (aka fac134)
bit 0 of the SCLP Read Info block. This coincidentally expands into the
space used for CPU entries, which means VMs running with the diag 318
capability may not be able to read information regarding all CPUs
unless the guest kernel supports an extended-length SCCB.

This feature is not supported in protected virtualization mode.

Signed-off-by: Collin Walling <address@hidden>
---
 hw/s390x/s390-virtio-ccw.c          | 45 +++++++++++++++++++++++++++++
 hw/s390x/sclp.c                     |  5 ++++
 include/hw/s390x/s390-virtio-ccw.h  |  1 +
 include/hw/s390x/sclp.h             |  3 ++
 target/s390x/cpu.c                  | 23 +++++++++++++++
 target/s390x/cpu.h                  |  4 +++
 target/s390x/cpu_features.h         |  1 +
 target/s390x/cpu_features_def.inc.h |  3 ++
 target/s390x/cpu_models.c           |  1 +
 target/s390x/gen-features.c         |  1 +
 target/s390x/kvm-stub.c             | 10 +++++++
 target/s390x/kvm.c                  | 40 +++++++++++++++++++++++++
 target/s390x/kvm_s390x.h            |  2 ++
 13 files changed, 139 insertions(+)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 45292fb5a8..9cc5f4cede 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -242,6 +242,40 @@ static void s390_create_sclpconsole(const char *type, 
Chardev *chardev)
     qdev_init_nofail(dev);
 }
 
+static int diag_318_post_load(void *opaque, int version_id)
+{
+    S390CcwMachineState *d = opaque;
+
+    s390_set_diag_318_info(d->diag_318_info);
+    return 0;
+}
+
+static int diag_318_pre_save(void *opaque)
+{
+    S390CcwMachineState *d = opaque;
+
+    s390_get_diag_318_info(&d->diag_318_info);
+    return 0;
+}
+
+static bool diag_318_needed(void *opaque)
+{
+    return s390_diag_318_is_allowed();
+}
+
+const VMStateDescription vmstate_diag_318 = {
+    .name = "vmstate_diag_318",
+    .post_load = diag_318_post_load,
+    .pre_save = diag_318_pre_save,
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = diag_318_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT64(diag_318_info, S390CcwMachineState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static void ccw_init(MachineState *machine)
 {
     int ret;
@@ -299,6 +333,8 @@ static void ccw_init(MachineState *machine)
 
     /* init the TOD clock */
     s390_init_tod();
+
+    vmstate_register(NULL, 0, &vmstate_diag_318, machine);
 }
 
 static void s390_cpu_plug(HotplugHandler *hotplug_dev,
@@ -404,6 +440,13 @@ static void s390_pv_prepare_reset(S390CcwMachineState *ms)
     s390_pv_perf_clear_reset();
 }
 
+static void s390_diag_318_reset(void)
+{
+    if (s390_diag_318_is_allowed()) {
+        s390_set_diag_318_info(0);
+    }
+}
+
 static void s390_machine_reset(MachineState *machine)
 {
     S390CcwMachineState *ms = S390_CCW_MACHINE(machine);
@@ -440,6 +483,7 @@ static void s390_machine_reset(MachineState *machine)
         subsystem_reset();
         s390_crypto_reset();
         s390_pv_prepare_reset(ms);
+        s390_diag_318_reset();
         CPU_FOREACH(t) {
             run_on_cpu(t, s390_do_cpu_full_reset, RUN_ON_CPU_NULL);
         }
@@ -452,6 +496,7 @@ static void s390_machine_reset(MachineState *machine)
          */
         subsystem_reset();
         s390_pv_prepare_reset(ms);
+        s390_diag_318_reset();
         CPU_FOREACH(t) {
             if (t == cs) {
                 continue;
diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
index bde4c5420e..b55fa955c8 100644
--- a/hw/s390x/sclp.c
+++ b/hw/s390x/sclp.c
@@ -152,6 +152,11 @@ static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb)
     s390_get_feat_block(S390_FEAT_TYPE_SCLP_CONF_CHAR_EXT,
                          read_info->conf_char_ext);
 
+    if (s390_has_feat(S390_FEAT_EXTENDED_LENGTH_SCCB)) {
+        s390_get_feat_block(S390_FEAT_TYPE_SCLP_FAC134,
+                            &read_info->fac134);
+    }
+
     read_info->facilities = cpu_to_be64(SCLP_HAS_CPU_INFO |
                                         SCLP_HAS_IOA_RECONFIG);
 
diff --git a/include/hw/s390x/s390-virtio-ccw.h 
b/include/hw/s390x/s390-virtio-ccw.h
index cd1dccc6e3..c9bf7b7096 100644
--- a/include/hw/s390x/s390-virtio-ccw.h
+++ b/include/hw/s390x/s390-virtio-ccw.h
@@ -30,6 +30,7 @@ typedef struct S390CcwMachineState {
     bool dea_key_wrap;
     bool pv;
     uint8_t loadparm[8];
+    uint64_t diag_318_info;
 } S390CcwMachineState;
 
 typedef struct S390CcwMachineClass {
diff --git a/include/hw/s390x/sclp.h b/include/hw/s390x/sclp.h
index ef2d63eae9..ccb9f0a676 100644
--- a/include/hw/s390x/sclp.h
+++ b/include/hw/s390x/sclp.h
@@ -133,6 +133,9 @@ typedef struct ReadInfo {
     uint16_t highest_cpu;
     uint8_t  _reserved5[124 - 122];     /* 122-123 */
     uint32_t hmfai;
+    uint8_t  _reserved7[134 - 128];     /* 128-133 */
+    uint8_t  fac134;
+    uint8_t  _reserved8[144 - 135];     /* 135-143 */
     struct CPUEntry entries[];
 } QEMU_PACKED ReadInfo;
 
diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
index f2ccf0a06a..367a54c173 100644
--- a/target/s390x/cpu.c
+++ b/target/s390x/cpu.c
@@ -446,6 +446,29 @@ void s390_enable_css_support(S390CPU *cpu)
         kvm_s390_enable_css_support(cpu);
     }
 }
+
+void s390_get_diag_318_info(uint64_t *info)
+{
+    if (kvm_enabled()) {
+        kvm_s390_get_diag_318_info(info);
+    }
+}
+
+void s390_set_diag_318_info(uint64_t info)
+{
+    if (kvm_enabled()) {
+        kvm_s390_set_diag_318_info(info);
+    }
+}
+
+bool s390_diag_318_is_allowed(void)
+{
+    if (kvm_enabled()) {
+        return s390_has_feat(S390_FEAT_DIAG_318) &&
+               s390_has_feat(S390_FEAT_EXTENDED_LENGTH_SCCB);
+    }
+    return false;
+}
 #endif
 
 static gchar *s390_gdb_arch_name(CPUState *cs)
diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index 035427521c..205738999e 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -769,6 +769,10 @@ void s390_cmma_reset(void);
 void s390_enable_css_support(S390CPU *cpu);
 int s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch_id,
                                 int vq, bool assign);
+void s390_get_diag_318_info(uint64_t *info);
+void s390_set_diag_318_info(uint64_t info);
+bool s390_diag_318_is_allowed(void);
+
 #ifndef CONFIG_USER_ONLY
 unsigned int s390_cpu_set_state(uint8_t cpu_state, S390CPU *cpu);
 #else
diff --git a/target/s390x/cpu_features.h b/target/s390x/cpu_features.h
index da695a8346..f74f7fc3a1 100644
--- a/target/s390x/cpu_features.h
+++ b/target/s390x/cpu_features.h
@@ -23,6 +23,7 @@ typedef enum {
     S390_FEAT_TYPE_STFL,
     S390_FEAT_TYPE_SCLP_CONF_CHAR,
     S390_FEAT_TYPE_SCLP_CONF_CHAR_EXT,
+    S390_FEAT_TYPE_SCLP_FAC134,
     S390_FEAT_TYPE_SCLP_CPU,
     S390_FEAT_TYPE_MISC,
     S390_FEAT_TYPE_PLO,
diff --git a/target/s390x/cpu_features_def.inc.h 
b/target/s390x/cpu_features_def.inc.h
index 3548d65a69..8c5bbfa0ea 100644
--- a/target/s390x/cpu_features_def.inc.h
+++ b/target/s390x/cpu_features_def.inc.h
@@ -122,6 +122,9 @@ DEF_FEAT(SIE_CMMA, "cmma", SCLP_CONF_CHAR_EXT, 1, "SIE: 
Collaborative-memory-man
 DEF_FEAT(SIE_PFMFI, "pfmfi", SCLP_CONF_CHAR_EXT, 9, "SIE: PFMF interpretation 
facility")
 DEF_FEAT(SIE_IBS, "ibs", SCLP_CONF_CHAR_EXT, 10, "SIE: 
Interlock-and-broadcast-suppression facility")
 
+/* Features exposed via SCLP SCCB Facilities byte 134 (bit numbers relative to 
byte-134) */
+DEF_FEAT(DIAG_318, "diag_318", SCLP_FAC134, 0, "Control program name and 
version codes")
+
 /* Features exposed via SCLP CPU info. */
 DEF_FEAT(SIE_F2, "sief2", SCLP_CPU, 4, "SIE: interception format 2 (Virtual 
SIE)")
 DEF_FEAT(SIE_SKEY, "skey", SCLP_CPU, 5, "SIE: Storage-key facility")
diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
index 7c32180269..1d8fc76f7b 100644
--- a/target/s390x/cpu_models.c
+++ b/target/s390x/cpu_models.c
@@ -827,6 +827,7 @@ static void check_consistency(const S390CPUModel *model)
         { S390_FEAT_PTFF_STOE, S390_FEAT_MULTIPLE_EPOCH },
         { S390_FEAT_PTFF_STOUE, S390_FEAT_MULTIPLE_EPOCH },
         { S390_FEAT_AP_QUEUE_INTERRUPT_CONTROL, S390_FEAT_AP },
+        { S390_FEAT_DIAG_318, S390_FEAT_EXTENDED_LENGTH_SCCB },
     };
     int i;
 
diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c
index 6857f657fb..a1f0a6f3c6 100644
--- a/target/s390x/gen-features.c
+++ b/target/s390x/gen-features.c
@@ -523,6 +523,7 @@ static uint16_t full_GEN12_GA1[] = {
     S390_FEAT_AP_FACILITIES_TEST,
     S390_FEAT_AP,
     S390_FEAT_EXTENDED_LENGTH_SCCB,
+    S390_FEAT_DIAG_318,
 };
 
 static uint16_t full_GEN12_GA2[] = {
diff --git a/target/s390x/kvm-stub.c b/target/s390x/kvm-stub.c
index aa185017a2..bb5c0d770a 100644
--- a/target/s390x/kvm-stub.c
+++ b/target/s390x/kvm-stub.c
@@ -120,3 +120,13 @@ void kvm_s390_stop_interrupt(S390CPU *cpu)
 void kvm_s390_restart_interrupt(S390CPU *cpu)
 {
 }
+
+int kvm_s390_get_diag_318_info(uint64_t *info)
+{
+    return 0;
+}
+
+int kvm_s390_set_diag_318_info(uint64_t info)
+{
+    return 0;
+}
diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index 380fb81822..5d7dc60c85 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -105,6 +105,7 @@
 
 #define DIAG_TIMEREVENT                 0x288
 #define DIAG_IPL                        0x308
+#define DIAG_SET_CONTROL_PROGRAM_CODES  0x318
 #define DIAG_KVM_HYPERCALL              0x500
 #define DIAG_KVM_BREAKPOINT             0x501
 
@@ -814,6 +815,28 @@ int kvm_s390_set_clock_ext(uint8_t tod_high, uint64_t 
tod_low)
     return kvm_vm_ioctl(kvm_state, KVM_SET_DEVICE_ATTR, &attr);
 }
 
+int kvm_s390_get_diag_318_info(uint64_t *info)
+{
+    struct kvm_device_attr attr = {
+        .group = KVM_S390_VM_MISC,
+        .attr = KVM_S390_VM_MISC_DIAG_318,
+        .addr = (uint64_t)info,
+    };
+
+    return kvm_vm_ioctl(kvm_state, KVM_GET_DEVICE_ATTR, &attr);
+}
+
+int kvm_s390_set_diag_318_info(uint64_t info)
+{
+    struct kvm_device_attr attr = {
+        .group = KVM_S390_VM_MISC,
+        .attr = KVM_S390_VM_MISC_DIAG_318,
+        .addr = (uint64_t)&info,
+    };
+
+    return kvm_vm_ioctl(kvm_state, KVM_SET_DEVICE_ATTR, &attr);
+}
+
 /**
  * kvm_s390_mem_op:
  * @addr:      the logical start address in guest memory
@@ -1601,6 +1624,14 @@ static int handle_sw_breakpoint(S390CPU *cpu, struct 
kvm_run *run)
     return -ENOENT;
 }
 
+static void kvm_handle_diag_318(struct kvm_run *run)
+{
+    uint64_t reg = (run->s390_sieic.ipa & 0x00f0) >> 4;
+    uint64_t info = run->s.regs.gprs[reg];
+
+    kvm_s390_set_diag_318_info(info);
+}
+
 #define DIAG_KVM_CODE_MASK 0x000000000000ffff
 
 static int handle_diag(S390CPU *cpu, struct kvm_run *run, uint32_t ipb)
@@ -1620,6 +1651,9 @@ static int handle_diag(S390CPU *cpu, struct kvm_run *run, 
uint32_t ipb)
     case DIAG_IPL:
         kvm_handle_diag_308(cpu, run);
         break;
+    case DIAG_SET_CONTROL_PROGRAM_CODES:
+        kvm_handle_diag_318(run);
+        break;
     case DIAG_KVM_HYPERCALL:
         r = handle_hypercall(cpu, run);
         break;
@@ -2460,6 +2494,12 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, 
Error **errp)
     /* Extended-Length SCCB is handled entirely within QEMU */
     set_bit(S390_FEAT_EXTENDED_LENGTH_SCCB, model->features);
 
+    /* Allow diag 0x318 iff KVM supported and not in PV mode */
+    if (!s390_is_pv() && kvm_vm_check_attr(kvm_state,
+        KVM_S390_VM_MISC, KVM_S390_VM_MISC_DIAG_318)) {
+        set_bit(S390_FEAT_DIAG_318, model->features);
+    }
+
     /* strip of features that are not part of the maximum model */
     bitmap_and(model->features, model->features, model->def->full_feat,
                S390_FEAT_MAX);
diff --git a/target/s390x/kvm_s390x.h b/target/s390x/kvm_s390x.h
index 6ab17c81b7..a9123b3821 100644
--- a/target/s390x/kvm_s390x.h
+++ b/target/s390x/kvm_s390x.h
@@ -32,6 +32,8 @@ int kvm_s390_get_clock(uint8_t *tod_high, uint64_t 
*tod_clock);
 int kvm_s390_get_clock_ext(uint8_t *tod_high, uint64_t *tod_clock);
 int kvm_s390_set_clock(uint8_t tod_high, uint64_t tod_clock);
 int kvm_s390_set_clock_ext(uint8_t tod_high, uint64_t tod_clock);
+int kvm_s390_get_diag_318_info(uint64_t *info);
+int kvm_s390_set_diag_318_info(uint64_t info);
 void kvm_s390_enable_css_support(S390CPU *cpu);
 int kvm_s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch,
                                     int vq, bool assign);
-- 
2.21.3