Merge remote-tracking branch 'remotes/cohuck/tags/s390x-20170224' into staging

A selection of s390x patches:
- cleanups, fixes and improvements
- program check loop detection (useful with the corresponding kernel
  patch)
- wire up virtio-crypto for ccw
- and finally support many virtqueues for virtio-ccw

# gpg: Signature made Fri 24 Feb 2017 09:19:19 GMT
# gpg:                using RSA key 0xDECF6B93C6F02FAF
# gpg: Good signature from "Cornelia Huck <huckc@linux.vnet.ibm.com>"
# gpg:                 aka "Cornelia Huck <cornelia.huck@de.ibm.com>"
# Primary key fingerprint: C3D0 D66D C362 4FF6 A8C0  18CE DECF 6B93 C6F0 2FAF

* remotes/cohuck/tags/s390x-20170224:
  s390x/css: handle format-0 TIC CCW correctly
  s390x/arch_dump: pass cpuid into notes sections
  s390x/arch_dump: use proper note name and note size
  virtio-ccw: support VIRTIO_QUEUE_MAX virtqueues
  s390x: bump ADAPTER_ROUTES_MAX_GSI
  virtio-ccw: check flic->adapter_routes_max_batch
  s390x: add property adapter_routes_max_batch
  virtio-ccw: Check the number of vqs in CCW_CMD_SET_IND
  virtio-ccw: add virtio-crypto-ccw device
  virtio-ccw: handle virtio 1 only devices
  s390x/flic: fail migration on source already
  s390x/kvm: detect some program check loops
  s390x/s390-virtio: get rid of DPRINTF

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

10 files changed, 250 insertions, 60 deletions

diff --git a/hw/intc/s390_flic.c b/hw/intc/s390_flic.c
index 6ab29efc65..bef4caf980 100644
--- a/hw/intc/s390_flic.c
+++ b/hw/intc/s390_flic.c
@@ -16,6 +16,8 @@
 #include "migration/qemu-file.h"
 #include "hw/s390x/s390_flic.h"
 #include "trace.h"
+#include "hw/qdev.h"
+#include "qapi/error.h"
 
 S390FLICState *s390_get_flic(void)
 {
@@ -85,6 +87,30 @@ static void qemu_s390_flic_class_init(ObjectClass *oc, void *data)
     fsc->clear_io_irq = qemu_s390_clear_io_flic;
 }
 
+static Property s390_flic_common_properties[] = {
+    DEFINE_PROP_UINT32("adapter_routes_max_batch", S390FLICState,
+                       adapter_routes_max_batch, ADAPTER_ROUTES_MAX_GSI),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void s390_flic_common_realize(DeviceState *dev, Error **errp)
+{
+    uint32_t max_batch = S390_FLIC_COMMON(dev)->adapter_routes_max_batch;
+
+    if (max_batch > ADAPTER_ROUTES_MAX_GSI) {
+        error_setg(errp, "flic adapter_routes_max_batch too big"
+                   "%d (%d allowed)", max_batch, ADAPTER_ROUTES_MAX_GSI);
+    }
+}
+
+static void s390_flic_class_init(ObjectClass *oc, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(oc);
+
+    dc->props = s390_flic_common_properties;
+    dc->realize = s390_flic_common_realize;
+}
+
 static const TypeInfo qemu_s390_flic_info = {
     .name          = TYPE_QEMU_S390_FLIC,
     .parent        = TYPE_S390_FLIC_COMMON,
@@ -92,10 +118,12 @@ static const TypeInfo qemu_s390_flic_info = {
     .class_init    = qemu_s390_flic_class_init,
 };
 
+
 static const TypeInfo s390_flic_common_info = {
     .name          = TYPE_S390_FLIC_COMMON,
     .parent        = TYPE_SYS_BUS_DEVICE,
     .instance_size = sizeof(S390FLICState),
+    .class_init    = s390_flic_class_init,
     .class_size    = sizeof(S390FLICStateClass),
 };
 
diff --git a/hw/intc/s390_flic_kvm.c b/hw/intc/s390_flic_kvm.c
index e86a84e49a..cc44bc4e1e 100644
--- a/hw/intc/s390_flic_kvm.c
+++ b/hw/intc/s390_flic_kvm.c
@@ -293,6 +293,7 @@ static int kvm_flic_save(QEMUFile *f, void *opaque, size_t size,
     int len = FLIC_SAVE_INITIAL_SIZE;
     void *buf;
     int count;
+    int r = 0;
 
     flic_disable_wait_pfault((struct KVMS390FLICState *) opaque);
 
@@ -303,7 +304,7 @@ static int kvm_flic_save(QEMUFile *f, void *opaque, size_t size,
          * migration state */
         error_report("flic: couldn't allocate memory");
         qemu_put_be64(f, FLIC_FAILED);
-        return 0;
+        return -ENOMEM;
     }
 
     count = __get_all_irqs(flic, &buf, len);
@@ -314,6 +315,7 @@ static int kvm_flic_save(QEMUFile *f, void *opaque, size_t size,
          * target system to fail when attempting to load irqs from the
          * migration state */
         qemu_put_be64(f, FLIC_FAILED);
+        r = count;
     } else {
         qemu_put_be64(f, count);
         qemu_put_buffer(f, (uint8_t *) buf,
@@ -321,7 +323,7 @@ static int kvm_flic_save(QEMUFile *f, void *opaque, size_t size,
     }
     g_free(buf);
 
-    return 0;
+    return r;
 }
 
 /**
diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index 0f2580d644..e32b2a4d42 100644
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -368,13 +368,16 @@ static CCW1 copy_ccw_from_guest(hwaddr addr, bool fmt1)
         ret.cda = be32_to_cpu(tmp1.cda);
     } else {
         cpu_physical_memory_read(addr, &tmp0, sizeof(tmp0));
-        ret.cmd_code = tmp0.cmd_code;
-        ret.flags = tmp0.flags;
-        ret.count = be16_to_cpu(tmp0.count);
-        ret.cda = be16_to_cpu(tmp0.cda1) | (tmp0.cda0 << 16);
-        if ((ret.cmd_code & 0x0f) == CCW_CMD_TIC) {
-            ret.cmd_code &= 0x0f;
+        if ((tmp0.cmd_code & 0x0f) == CCW_CMD_TIC) {
+            ret.cmd_code = CCW_CMD_TIC;
+            ret.flags = 0;
+            ret.count = 0;
+        } else {
+            ret.cmd_code = tmp0.cmd_code;
+            ret.flags = tmp0.flags;
+            ret.count = be16_to_cpu(tmp0.count);
         }
+        ret.cda = be16_to_cpu(tmp0.cda1) | (tmp0.cda0 << 16);
     }
     return ret;
 }
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index e9a676797a..4f0d62b2d8 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -63,7 +63,7 @@ static int virtio_ccw_hcall_notify(const uint64_t *args)
     if (!sch || !css_subch_visible(sch)) {
         return -EINVAL;
     }
-    if (queue >= VIRTIO_CCW_QUEUE_MAX) {
+    if (queue >= VIRTIO_QUEUE_MAX) {
         return -EINVAL;
     }
     virtio_queue_notify(virtio_ccw_get_vdev(sch), queue);
@@ -336,7 +336,12 @@ static const TypeInfo ccw_machine_info = {
     type_init(ccw_machine_register_##suffix)
 
 #define CCW_COMPAT_2_8 \
-        HW_COMPAT_2_8
+        HW_COMPAT_2_8 \
+        {\
+            .driver   = TYPE_S390_FLIC_COMMON,\
+            .property = "adapter_routes_max_batch",\
+            .value    = "64",\
+        },
 
 #define CCW_COMPAT_2_7 \
         HW_COMPAT_2_7
diff --git a/hw/s390x/s390-virtio.c b/hw/s390x/s390-virtio.c
index 7a3a7fe5fd..9cfb09057e 100644
--- a/hw/s390x/s390-virtio.c
+++ b/hw/s390x/s390-virtio.c
@@ -44,16 +44,6 @@
 #include "hw/s390x/ipl.h"
 #include "cpu.h"
 
-//#define DEBUG_S390
-
-#ifdef DEBUG_S390
-#define DPRINTF(fmt, ...) \
-    do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)
-#else
-#define DPRINTF(fmt, ...) \
-    do { } while (0)
-#endif
-
 #define MAX_BLK_DEVS                    10
 
 #define S390_TOD_CLOCK_VALUE_MISSING    0x00
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 63c46373fb..00b3bde4e9 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -35,6 +35,8 @@
 #include "trace.h"
 #include "hw/s390x/css-bridge.h"
 
+#define NR_CLASSIC_INDICATOR_BITS 64
+
 static void virtio_ccw_bus_new(VirtioBusState *bus, size_t bus_size,
                                VirtioCcwDevice *dev);
 
@@ -126,7 +128,7 @@ static int virtio_ccw_set_vqs(SubchDev *sch, VqInfoBlock *info,
     uint16_t num = info ? info->num : linfo->num;
     uint64_t desc = info ? info->desc : linfo->queue;
 
-    if (index >= VIRTIO_CCW_QUEUE_MAX) {
+    if (index >= VIRTIO_QUEUE_MAX) {
         return -EINVAL;
     }
 
@@ -162,7 +164,7 @@ static int virtio_ccw_set_vqs(SubchDev *sch, VqInfoBlock *info,
         virtio_queue_set_vector(vdev, index, index);
     }
     /* tell notify handler in case of config change */
-    vdev->config_vector = VIRTIO_CCW_QUEUE_MAX;
+    vdev->config_vector = VIRTIO_QUEUE_MAX;
     return 0;
 }
 
@@ -280,6 +282,15 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
                                    ccw.cmd_code);
     check_len = !((ccw.flags & CCW_FLAG_SLI) && !(ccw.flags & CCW_FLAG_DC));
 
+    if (dev->force_revision_1 && dev->revision < 0 &&
+        ccw.cmd_code != CCW_CMD_SET_VIRTIO_REV) {
+        /*
+         * virtio-1 drivers must start with negotiating to a revision >= 1,
+         * so post a command reject for all other commands
+         */
+        return -ENOSYS;
+    }
+
     /* Look at the command. */
     switch (ccw.cmd_code) {
     case CCW_CMD_SET_VQ:
@@ -500,6 +511,11 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
             ret = -ENOSYS;
             break;
         }
+        if (virtio_get_num_queues(vdev) > NR_CLASSIC_INDICATOR_BITS) {
+            /* More queues than indicator bits --> trigger a reject */
+            ret = -ENOSYS;
+            break;
+        }
         if (!ccw.cda) {
             ret = -EFAULT;
         } else {
@@ -549,7 +565,7 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
                                                     ccw.cda,
                                                     MEMTXATTRS_UNSPECIFIED,
                                                     NULL);
-            if (vq_config.index >= VIRTIO_CCW_QUEUE_MAX) {
+            if (vq_config.index >= VIRTIO_QUEUE_MAX) {
                 ret = -EINVAL;
                 break;
             }
@@ -638,7 +654,8 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
          * need to fetch it here. Nothing to do for now, though.
          */
         if (dev->revision >= 0 ||
-            revinfo.revision > virtio_ccw_rev_max(dev)) {
+            revinfo.revision > virtio_ccw_rev_max(dev) ||
+            (dev->force_revision_1 && !revinfo.revision)) {
             ret = -ENOSYS;
             break;
         }
@@ -669,6 +686,12 @@ static void virtio_ccw_device_realize(VirtioCcwDevice *dev, Error **errp)
     if (!sch) {
         return;
     }
+    if (!virtio_ccw_rev_max(dev) && dev->force_revision_1) {
+        error_setg(&err, "Invalid value of property max_rev "
+                   "(is %d expected >= 1)", virtio_ccw_rev_max(dev));
+        error_propagate(errp, err);
+        return;
+    }
 
     sch->driver_data = dev;
     sch->ccw_cb = virtio_ccw_cb;
@@ -878,6 +901,24 @@ static void virtio_ccw_rng_realize(VirtioCcwDevice *ccw_dev, Error **errp)
                              NULL);
 }
 
+static void virtio_ccw_crypto_realize(VirtioCcwDevice *ccw_dev, Error **errp)
+{
+    VirtIOCryptoCcw *dev = VIRTIO_CRYPTO_CCW(ccw_dev);
+    DeviceState *vdev = DEVICE(&dev->vdev);
+    Error *err = NULL;
+
+    qdev_set_parent_bus(vdev, BUS(&ccw_dev->bus));
+    object_property_set_bool(OBJECT(vdev), true, "realized", &err);
+    if (err) {
+        error_propagate(errp, err);
+        return;
+    }
+
+    object_property_set_link(OBJECT(vdev),
+                             OBJECT(dev->vdev.conf.cryptodev), "cryptodev",
+                             NULL);
+}
+
 /* DeviceState to VirtioCcwDevice. Note: used on datapath,
  * be careful and test performance if you change this.
  */
@@ -919,11 +960,11 @@ static void virtio_ccw_notify(DeviceState *d, uint16_t vector)
     uint64_t indicators;
 
     /* queue indicators + secondary indicators */
-    if (vector >= VIRTIO_CCW_QUEUE_MAX + 64) {
+    if (vector >= VIRTIO_QUEUE_MAX + 64) {
         return;
     }
 
-    if (vector < VIRTIO_CCW_QUEUE_MAX) {
+    if (vector < VIRTIO_QUEUE_MAX) {
         if (!dev->indicators) {
             return;
         }
@@ -1278,15 +1319,22 @@ static void virtio_ccw_device_plugged(DeviceState *d, Error **errp)
     CcwDevice *ccw_dev = CCW_DEVICE(d);
     SubchDev *sch = ccw_dev->sch;
     int n = virtio_get_num_queues(vdev);
+    S390FLICState *flic = s390_get_flic();
 
     if (!virtio_has_feature(vdev->host_features, VIRTIO_F_VERSION_1)) {
         dev->max_rev = 0;
     }
 
-    if (virtio_get_num_queues(vdev) > VIRTIO_CCW_QUEUE_MAX) {
+    if (virtio_get_num_queues(vdev) > VIRTIO_QUEUE_MAX) {
+        error_setg(errp, "The number of virtqueues %d "
+                   "exceeds virtio limit %d", n,
+                   VIRTIO_QUEUE_MAX);
+        return;
+    }
+    if (virtio_get_num_queues(vdev) > flic->adapter_routes_max_batch) {
         error_setg(errp, "The number of virtqueues %d "
-                   "exceeds ccw limit %d", n,
-                   VIRTIO_CCW_QUEUE_MAX);
+                   "exceeds flic adapter route limit %d", n,
+                   flic->adapter_routes_max_batch);
         return;
     }
 
@@ -1518,6 +1566,48 @@ static const TypeInfo virtio_ccw_rng = {
     .class_init    = virtio_ccw_rng_class_init,
 };
 
+static Property virtio_ccw_crypto_properties[] = {
+    DEFINE_PROP_CSS_DEV_ID("devno", VirtioCcwDevice, parent_obj.bus_id),
+    DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
+                    VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
+    DEFINE_PROP_UINT32("max_revision", VirtioCcwDevice, max_rev,
+                       VIRTIO_CCW_MAX_REV),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void virtio_ccw_crypto_instance_init(Object *obj)
+{
+    VirtIOCryptoCcw *dev = VIRTIO_CRYPTO_CCW(obj);
+    VirtioCcwDevice *ccw_dev = VIRTIO_CCW_DEVICE(obj);
+
+    ccw_dev->force_revision_1 = true;
+    virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
+                                TYPE_VIRTIO_CRYPTO);
+
+    object_property_add_alias(obj, "cryptodev", OBJECT(&dev->vdev),
+                              "cryptodev", &error_abort);
+}
+
+static void virtio_ccw_crypto_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    VirtIOCCWDeviceClass *k = VIRTIO_CCW_DEVICE_CLASS(klass);
+
+    k->realize = virtio_ccw_crypto_realize;
+    k->exit = virtio_ccw_exit;
+    dc->reset = virtio_ccw_reset;
+    dc->props = virtio_ccw_crypto_properties;
+    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+}
+
+static const TypeInfo virtio_ccw_crypto = {
+    .name          = TYPE_VIRTIO_CRYPTO_CCW,
+    .parent        = TYPE_VIRTIO_CCW_DEVICE,
+    .instance_size = sizeof(VirtIOCryptoCcw),
+    .instance_init = virtio_ccw_crypto_instance_init,
+    .class_init    = virtio_ccw_crypto_class_init,
+};
+
 static void virtio_ccw_busdev_realize(DeviceState *dev, Error **errp)
 {
     VirtioCcwDevice *_dev = (VirtioCcwDevice *)dev;
@@ -1720,6 +1810,7 @@ static void virtio_ccw_register(void)
 #ifdef CONFIG_VHOST_VSOCK
     type_register_static(&vhost_vsock_ccw_info);
 #endif
+    type_register_static(&virtio_ccw_crypto);
 }
 
 type_init(virtio_ccw_register)
diff --git a/hw/s390x/virtio-ccw.h b/hw/s390x/virtio-ccw.h
index 77d10f1671..41d4010378 100644
--- a/hw/s390x/virtio-ccw.h
+++ b/hw/s390x/virtio-ccw.h
@@ -22,6 +22,7 @@
 #endif
 #include "hw/virtio/virtio-balloon.h"
 #include "hw/virtio/virtio-rng.h"
+#include "hw/virtio/virtio-crypto.h"
 #include "hw/virtio/virtio-bus.h"
 #ifdef CONFIG_VHOST_VSOCK
 #include "hw/virtio/vhost-vsock.h"
@@ -94,6 +95,7 @@ struct VirtioCcwDevice {
     IndAddr *indicators2;
     IndAddr *summary_indicator;
     uint64_t ind_bit;
+    bool force_revision_1;
 };
 
 /* The maximum virtio revision we support. */
@@ -182,6 +184,17 @@ typedef struct VirtIORNGCcw {
     VirtIORNG vdev;
 } VirtIORNGCcw;
 
+/* virtio-crypto-ccw */
+
+#define TYPE_VIRTIO_CRYPTO_CCW "virtio-crypto-ccw"
+#define VIRTIO_CRYPTO_CCW(obj) \
+        OBJECT_CHECK(VirtIOCryptoCcw, (obj), TYPE_VIRTIO_CRYPTO_CCW)
+
+typedef struct VirtIOCryptoCcw {
+    VirtioCcwDevice parent_obj;
+    VirtIOCrypto vdev;
+} VirtIOCryptoCcw;
+
 VirtIODevice *virtio_ccw_get_vdev(SubchDev *sch);
 
 #ifdef CONFIG_VIRTFS
diff --git a/include/hw/s390x/s390_flic.h b/include/hw/s390x/s390_flic.h
index 9094edadf5..f9e6890c90 100644
--- a/include/hw/s390x/s390_flic.h
+++ b/include/hw/s390x/s390_flic.h
@@ -17,8 +17,13 @@
 #include "hw/s390x/adapter.h"
 #include "hw/virtio/virtio.h"
 
-#define ADAPTER_ROUTES_MAX_GSI 64
-#define VIRTIO_CCW_QUEUE_MAX ADAPTER_ROUTES_MAX_GSI
+/*
+ * Reserve enough gsis to accommodate all virtio devices.
+ * If any other user of adapter routes needs more of these,
+ * we need to bump the value; but virtio looks like the
+ * maximum right now.
+ */
+#define ADAPTER_ROUTES_MAX_GSI VIRTIO_QUEUE_MAX
 
 typedef struct AdapterRoutes {
     AdapterInfo adapter;
@@ -32,6 +37,8 @@ typedef struct AdapterRoutes {
 
 typedef struct S390FLICState {
     SysBusDevice parent_obj;
+    /* to limit AdapterRoutes.num_routes for compat */
+    uint32_t adapter_routes_max_batch;
 
 } S390FLICState;
 
diff --git a/target/s390x/arch_dump.c b/target/s390x/arch_dump.c
index 4731869f6b..105ae9a5d8 100644
--- a/target/s390x/arch_dump.c
+++ b/target/s390x/arch_dump.c
@@ -59,8 +59,7 @@ typedef struct S390xElfVregsHiStruct S390xElfVregsHi;
 
 typedef struct noteStruct {
     Elf64_Nhdr hdr;
-    char name[5];
-    char pad3[3];
+    char name[8];
     union {
         S390xElfPrstatus prstatus;
         S390xElfFpregset fpregset;
@@ -74,7 +73,7 @@ typedef struct noteStruct {
     } contents;
 } QEMU_PACKED Note;
 
-static void s390x_write_elf64_prstatus(Note *note, S390CPU *cpu)
+static void s390x_write_elf64_prstatus(Note *note, S390CPU *cpu, int id)
 {
     int i;
     S390xUserRegs *regs;
@@ -88,9 +87,10 @@ static void s390x_write_elf64_prstatus(Note *note, S390CPU *cpu)
         regs->acrs[i] = cpu_to_be32(cpu->env.aregs[i]);
         regs->gprs[i] = cpu_to_be64(cpu->env.regs[i]);
     }
+    note->contents.prstatus.pid = id;
 }
 
-static void s390x_write_elf64_fpregset(Note *note, S390CPU *cpu)
+static void s390x_write_elf64_fpregset(Note *note, S390CPU *cpu, int id)
 {
     int i;
     CPUS390XState *cs = &cpu->env;
@@ -102,7 +102,7 @@ static void s390x_write_elf64_fpregset(Note *note, S390CPU *cpu)
     }
 }
 
-static void s390x_write_elf64_vregslo(Note *note, S390CPU *cpu)
+static void s390x_write_elf64_vregslo(Note *note, S390CPU *cpu,  int id)
 {
     int i;
 
@@ -112,7 +112,7 @@ static void s390x_write_elf64_vregslo(Note *note, S390CPU *cpu)
     }
 }
 
-static void s390x_write_elf64_vregshi(Note *note, S390CPU *cpu)
+static void s390x_write_elf64_vregshi(Note *note, S390CPU *cpu, int id)
 {
     int i;
     S390xElfVregsHi *temp_vregshi;
@@ -126,25 +126,25 @@ static void s390x_write_elf64_vregshi(Note *note, S390CPU *cpu)
     }
 }
 
-static void s390x_write_elf64_timer(Note *note, S390CPU *cpu)
+static void s390x_write_elf64_timer(Note *note, S390CPU *cpu, int id)
 {
     note->hdr.n_type = cpu_to_be32(NT_S390_TIMER);
     note->contents.timer = cpu_to_be64((uint64_t)(cpu->env.cputm));
 }
 
-static void s390x_write_elf64_todcmp(Note *note, S390CPU *cpu)
+static void s390x_write_elf64_todcmp(Note *note, S390CPU *cpu, int id)
 {
     note->hdr.n_type = cpu_to_be32(NT_S390_TODCMP);
     note->contents.todcmp = cpu_to_be64((uint64_t)(cpu->env.ckc));
 }
 
-static void s390x_write_elf64_todpreg(Note *note, S390CPU *cpu)
+static void s390x_write_elf64_todpreg(Note *note, S390CPU *cpu, int id)
 {
     note->hdr.n_type = cpu_to_be32(NT_S390_TODPREG);
     note->contents.todpreg = cpu_to_be32((uint32_t)(cpu->env.todpr));
 }
 
-static void s390x_write_elf64_ctrs(Note *note, S390CPU *cpu)
+static void s390x_write_elf64_ctrs(Note *note, S390CPU *cpu, int id)
 {
     int i;
 
@@ -155,20 +155,26 @@ static void s390x_write_elf64_ctrs(Note *note, S390CPU *cpu)
     }
 }
 
-static void s390x_write_elf64_prefix(Note *note, S390CPU *cpu)
+static void s390x_write_elf64_prefix(Note *note, S390CPU *cpu, int id)
 {
     note->hdr.n_type = cpu_to_be32(NT_S390_PREFIX);
     note->contents.prefix = cpu_to_be32((uint32_t)(cpu->env.psa));
 }
 
 
-static const struct NoteFuncDescStruct {
+typedef struct NoteFuncDescStruct {
     int contents_size;
-    void (*note_contents_func)(Note *note, S390CPU *cpu);
-} note_func[] = {
+    void (*note_contents_func)(Note *note, S390CPU *cpu, int id);
+} NoteFuncDesc;
+
+static const NoteFuncDesc note_core[] = {
     {sizeof(((Note *)0)->contents.prstatus), s390x_write_elf64_prstatus},
-    {sizeof(((Note *)0)->contents.prefix),   s390x_write_elf64_prefix},
     {sizeof(((Note *)0)->contents.fpregset), s390x_write_elf64_fpregset},
+    { 0, NULL}
+};
+
+static const NoteFuncDesc note_linux[] = {
+    {sizeof(((Note *)0)->contents.prefix),   s390x_write_elf64_prefix},
     {sizeof(((Note *)0)->contents.ctrs),     s390x_write_elf64_ctrs},
     {sizeof(((Note *)0)->contents.timer),    s390x_write_elf64_timer},
     {sizeof(((Note *)0)->contents.todcmp),   s390x_write_elf64_todcmp},
@@ -178,25 +184,23 @@ static const struct NoteFuncDescStruct {
     { 0, NULL}
 };
 
-typedef struct NoteFuncDescStruct NoteFuncDesc;
-
-
-static int s390x_write_all_elf64_notes(const char *note_name,
+static int s390x_write_elf64_notes(const char *note_name,
                                        WriteCoreDumpFunction f,
                                        S390CPU *cpu, int id,
-                                       void *opaque)
+                                       void *opaque,
+                                       const NoteFuncDesc *funcs)
 {
     Note note;
     const NoteFuncDesc *nf;
     int note_size;
     int ret = -1;
 
-    for (nf = note_func; nf->note_contents_func; nf++) {
+    for (nf = funcs; nf->note_contents_func; nf++) {
         memset(&note, 0, sizeof(note));
-        note.hdr.n_namesz = cpu_to_be32(sizeof(note.name));
+        note.hdr.n_namesz = cpu_to_be32(strlen(note_name) + 1);
         note.hdr.n_descsz = cpu_to_be32(nf->contents_size);
         strncpy(note.name, note_name, sizeof(note.name));
-        (*nf->note_contents_func)(&note, cpu);
+        (*nf->note_contents_func)(&note, cpu, id);
 
         note_size = sizeof(note) - sizeof(note.contents) + nf->contents_size;
         ret = f(&note, note_size, opaque);
@@ -215,7 +219,13 @@ int s390_cpu_write_elf64_note(WriteCoreDumpFunction f, CPUState *cs,
                               int cpuid, void *opaque)
 {
     S390CPU *cpu = S390_CPU(cs);
-    return s390x_write_all_elf64_notes("CORE", f, cpu, cpuid, opaque);
+    int r;
+
+    r = s390x_write_elf64_notes("CORE", f, cpu, cpuid, opaque, note_core);
+    if (r) {
+        return r;
+    }
+    return s390x_write_elf64_notes("LINUX", f, cpu, cpuid, opaque, note_linux);
 }
 
 int cpu_get_dump_info(ArchDumpInfo *info,
@@ -230,7 +240,7 @@ int cpu_get_dump_info(ArchDumpInfo *info,
 
 ssize_t cpu_get_note_size(int class, int machine, int nr_cpus)
 {
-    int name_size = 8; /* "CORE" or "QEMU" rounded */
+    int name_size = 8; /* "LINUX" or "CORE" + pad */
     size_t elf_note_size = 0;
     int note_head_size;
     const NoteFuncDesc *nf;
@@ -240,7 +250,11 @@ ssize_t cpu_get_note_size(int class, int machine, int nr_cpus)
 
     note_head_size = sizeof(Elf64_Nhdr);
 
-    for (nf = note_func; nf->note_contents_func; nf++) {
+    for (nf = note_core; nf->note_contents_func; nf++) {
+        elf_note_size = elf_note_size + note_head_size + name_size +
+                        nf->contents_size;
+    }
+    for (nf = note_linux; nf->note_contents_func; nf++) {
         elf_note_size = elf_note_size + note_head_size + name_size +
                         nf->contents_size;
     }
diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index 25367807f4..5ec050cf89 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -1867,6 +1867,40 @@ static void unmanageable_intercept(S390CPU *cpu, const char *str, int pswoffset)
     qemu_system_guest_panicked(NULL);
 }
 
+/* try to detect pgm check loops */
+static int handle_oper_loop(S390CPU *cpu, struct kvm_run *run)
+{
+    CPUState *cs = CPU(cpu);
+    PSW oldpsw, newpsw;
+
+    cpu_synchronize_state(cs);
+    newpsw.mask = ldq_phys(cs->as, cpu->env.psa +
+                           offsetof(LowCore, program_new_psw));
+    newpsw.addr = ldq_phys(cs->as, cpu->env.psa +
+                           offsetof(LowCore, program_new_psw) + 8);
+    oldpsw.mask  = run->psw_mask;
+    oldpsw.addr  = run->psw_addr;
+    /*
+     * Avoid endless loops of operation exceptions, if the pgm new
+     * PSW will cause a new operation exception.
+     * The heuristic checks if the pgm new psw is within 6 bytes before
+     * the faulting psw address (with same DAT, AS settings) and the
+     * new psw is not a wait psw and the fault was not triggered by
+     * problem state. In that case go into crashed state.
+     */
+
+    if (oldpsw.addr - newpsw.addr <= 6 &&
+        !(newpsw.mask & PSW_MASK_WAIT) &&
+        !(oldpsw.mask & PSW_MASK_PSTATE) &&
+        (newpsw.mask & PSW_MASK_ASC) == (oldpsw.mask & PSW_MASK_ASC) &&
+        (newpsw.mask & PSW_MASK_DAT) == (oldpsw.mask & PSW_MASK_DAT)) {
+        unmanageable_intercept(cpu, "operation exception loop",
+                               offsetof(LowCore, program_new_psw));
+        return EXCP_HALTED;
+    }
+    return 0;
+}
+
 static int handle_intercept(S390CPU *cpu)
 {
     CPUState *cs = CPU(cpu);
@@ -1914,11 +1948,14 @@ static int handle_intercept(S390CPU *cpu)
             r = EXCP_HALTED;
             break;
         case ICPT_OPEREXC:
-            /* currently only instr 0x0000 after enabled via capability */
+            /* check for break points */
             r = handle_sw_breakpoint(cpu, run);
             if (r == -ENOENT) {
-                enter_pgmcheck(cpu, PGM_OPERATION);
-                r = 0;
+                /* Then check for potential pgm check loops */
+                r = handle_oper_loop(cpu, run);
+                if (r == 0) {
+                    enter_pgmcheck(cpu, PGM_OPERATION);
+                }
             }
             break;
         case ICPT_SOFT_INTERCEPT: