Merge remote-tracking branch 'remotes/borntraeger/tags/kvm-s390-20140901' into staging

s390x/kvm: Several updates/fixes/features

1. s390x/kvm: avoid synchronize_rcu's in kernel
----------------------------------------------
The first patches change s390x/kvm code to issue VCPU specific ioctls
from the VCPU thread. This will avoid unnecessary synchronize_rcu in
the kernel, which caused a noticably slowdown with many guest CPUs.
It speeds up all start/restart/reset operations involving cpus
drastically.

2. s390-ccw.img: block size and DASD format support
---------------------------------------------------
The second part changes the s390-ccw bios to IPL (boot)  more disk
formats than before. Furthermore a small fix is made to the console
output of the bios.

3. s390: Support for Hotplug of Standby Memory
----------------------------------------------
The third part adds support in s390 for a pool of standby memory,
which can be set online/offline by the guest (ie, via chmem).
The standby pool of memory is allocated as the difference between
the initial memory setting and the maxmem setting.
As part of this work, additional results are provided for the
Read SCP Information SCLP, and new implentation is added for the
Read Storage Element Information, Attach Storage Element,
Assign Storage and Unassign Storage SCLPs, which enables the s390
guest to manipulate the standby memory pool.

This patchset is based on work originally done by Jeng-Fang (Nick)
Wang.

Sample qemu command snippet:

qemu -machine s390-ccw-virtio  -m 1024M,maxmem=2048M,slots=32 -enable-kvm

This will allocate 1024M of active memory, and another 1024M
of standby memory.  Example output from s390-tools lsmem:
=============================================================================
0x0000000000000000-0x000000000fffffff        256  online   no         0-127
0x0000000010000000-0x000000001fffffff        256  online   yes        128-255
0x0000000020000000-0x000000003fffffff        512  online   no         256-511
0x0000000040000000-0x000000007fffffff       1024  offline  -          512-1023

Memory device size  : 2 MB
Memory block size   : 256 MB
Total online memory : 1024 MB
Total offline memory: 1024 MB

The guest can dynamically enable part or all of the standby pool
via the s390-tools chmem, for example:

chmem -e 512M

And can attempt to dynamically disable:

chmem -d 512M

4. s390x/gdb: various fixes
---------------------------
* Patch 1 fixes a bug where the cc was changed accidentally.
* Patch 2 adds the gdb feature XML files for s390x
* Patch 3 Define acr and fpr registers as coprocessor registers. This allows us
   to reuse the feature XML files.
* Patch 4 whitespace fixes

# gpg: Signature made Mon 01 Sep 2014 12:53:39 BST using RSA key ID B5A61C7C
# gpg: Can't check signature: public key not found

* remotes/borntraeger/tags/kvm-s390-20140901:
  s390x/gdb: coding style fixes
  s390x/gdb: generate target.xml and handle fp/ac as coprocessors
  s390x/gdb: add the feature xml files for s390x
  s390x/gdb: don't touch the cc if tcg is not enabled
  sclp-s390: Add memory hotplug SCLPs
  s390-virtio: Apply same memory boundaries as virtio-ccw
  virtio-ccw: Include standby memory when calculating storage increment
  sclp-s390: Add device to manage s390 memory hotplug
  pc-bios/s390-ccw.img binary update
  pc-bios/s390-ccw: Do proper console setup
  pc-bios/s390-ccw: IPL from DASD with format variations
  pc-bios/s390-ccw Really big EAV ECKD DASD handling
  pc-bios/s390-ccw Improve ECKD informational message
  pc-bios/s390-ccw: handle more ECKD DASD block sizes
  pc-bios/s390-ccw: support all virtio block size
  s390x/kvm: execute the first cpu reset on the vcpu thread
  s390x/kvm: execute "system reset" cpu resets on the vcpu thread
  s390x/kvm: execute sigp orders on the target vcpu thread
  s390x/kvm: run guest triggered resets on the target vcpu thread

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

20 files changed, 692 insertions, 173 deletions

diff --git a/configure b/configure
index 2063cf6a3c..15201f980f 100755
--- a/configure
+++ b/configure
@@ -5093,6 +5093,7 @@ case "$target_name" in
     echo "TARGET_ABI32=y" >> $config_target_mak
   ;;
   s390x)
+    gdb_xml_files="s390x-core64.xml s390-acr.xml s390-fpr.xml"
   ;;
   unicore32)
   ;;
diff --git a/gdb-xml/s390-acr.xml b/gdb-xml/s390-acr.xml
new file mode 100644
index 0000000000..71dfb20528
--- /dev/null
+++ b/gdb-xml/s390-acr.xml
@@ -0,0 +1,26 @@
+<?xml version="1.0"?>
+<!-- Copyright (C) 2010-2014 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.s390.acr">
+  <reg name="acr0" bitsize="32" type="uint32" group="access"/>
+  <reg name="acr1" bitsize="32" type="uint32" group="access"/>
+  <reg name="acr2" bitsize="32" type="uint32" group="access"/>
+  <reg name="acr3" bitsize="32" type="uint32" group="access"/>
+  <reg name="acr4" bitsize="32" type="uint32" group="access"/>
+  <reg name="acr5" bitsize="32" type="uint32" group="access"/>
+  <reg name="acr6" bitsize="32" type="uint32" group="access"/>
+  <reg name="acr7" bitsize="32" type="uint32" group="access"/>
+  <reg name="acr8" bitsize="32" type="uint32" group="access"/>
+  <reg name="acr9" bitsize="32" type="uint32" group="access"/>
+  <reg name="acr10" bitsize="32" type="uint32" group="access"/>
+  <reg name="acr11" bitsize="32" type="uint32" group="access"/>
+  <reg name="acr12" bitsize="32" type="uint32" group="access"/>
+  <reg name="acr13" bitsize="32" type="uint32" group="access"/>
+  <reg name="acr14" bitsize="32" type="uint32" group="access"/>
+  <reg name="acr15" bitsize="32" type="uint32" group="access"/>
+</feature>
diff --git a/gdb-xml/s390-fpr.xml b/gdb-xml/s390-fpr.xml
new file mode 100644
index 0000000000..7de0c136ad
--- /dev/null
+++ b/gdb-xml/s390-fpr.xml
@@ -0,0 +1,27 @@
+<?xml version="1.0"?>
+<!-- Copyright (C) 2010-2014 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.s390.fpr">
+  <reg name="fpc" bitsize="32" type="uint32" group="float"/>
+  <reg name="f0" bitsize="64" type="ieee_double" group="float"/>
+  <reg name="f1" bitsize="64" type="ieee_double" group="float"/>
+  <reg name="f2" bitsize="64" type="ieee_double" group="float"/>
+  <reg name="f3" bitsize="64" type="ieee_double" group="float"/>
+  <reg name="f4" bitsize="64" type="ieee_double" group="float"/>
+  <reg name="f5" bitsize="64" type="ieee_double" group="float"/>
+  <reg name="f6" bitsize="64" type="ieee_double" group="float"/>
+  <reg name="f7" bitsize="64" type="ieee_double" group="float"/>
+  <reg name="f8" bitsize="64" type="ieee_double" group="float"/>
+  <reg name="f9" bitsize="64" type="ieee_double" group="float"/>
+  <reg name="f10" bitsize="64" type="ieee_double" group="float"/>
+  <reg name="f11" bitsize="64" type="ieee_double" group="float"/>
+  <reg name="f12" bitsize="64" type="ieee_double" group="float"/>
+  <reg name="f13" bitsize="64" type="ieee_double" group="float"/>
+  <reg name="f14" bitsize="64" type="ieee_double" group="float"/>
+  <reg name="f15" bitsize="64" type="ieee_double" group="float"/>
+</feature>
diff --git a/gdb-xml/s390x-core64.xml b/gdb-xml/s390x-core64.xml
new file mode 100644
index 0000000000..15234378ee
--- /dev/null
+++ b/gdb-xml/s390x-core64.xml
@@ -0,0 +1,28 @@
+<?xml version="1.0"?>
+<!-- Copyright (C) 2010-2014 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.s390.core">
+  <reg name="pswm" bitsize="64" type="uint64" group="psw"/>
+  <reg name="pswa" bitsize="64" type="uint64" group="psw"/>
+  <reg name="r0" bitsize="64" type="uint64" group="general"/>
+  <reg name="r1" bitsize="64" type="uint64" group="general"/>
+  <reg name="r2" bitsize="64" type="uint64" group="general"/>
+  <reg name="r3" bitsize="64" type="uint64" group="general"/>
+  <reg name="r4" bitsize="64" type="uint64" group="general"/>
+  <reg name="r5" bitsize="64" type="uint64" group="general"/>
+  <reg name="r6" bitsize="64" type="uint64" group="general"/>
+  <reg name="r7" bitsize="64" type="uint64" group="general"/>
+  <reg name="r8" bitsize="64" type="uint64" group="general"/>
+  <reg name="r9" bitsize="64" type="uint64" group="general"/>
+  <reg name="r10" bitsize="64" type="uint64" group="general"/>
+  <reg name="r11" bitsize="64" type="uint64" group="general"/>
+  <reg name="r12" bitsize="64" type="uint64" group="general"/>
+  <reg name="r13" bitsize="64" type="uint64" group="general"/>
+  <reg name="r14" bitsize="64" type="uint64" group="general"/>
+  <reg name="r15" bitsize="64" type="uint64" group="general"/>
+</feature>
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 004b2c20c5..e538b1f686 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -17,6 +17,7 @@
 #include "ioinst.h"
 #include "css.h"
 #include "virtio-ccw.h"
+#include "qemu/config-file.h"
 
 #define TYPE_S390_CCW_MACHINE               "s390-ccw-machine"
 
@@ -86,17 +87,35 @@ static void ccw_init(MachineState *machine)
     ram_addr_t my_ram_size = machine->ram_size;
     MemoryRegion *sysmem = get_system_memory();
     MemoryRegion *ram = g_new(MemoryRegion, 1);
-    int shift = 0;
+    sclpMemoryHotplugDev *mhd = init_sclp_memory_hotplug_dev();
     uint8_t *storage_keys;
     int ret;
     VirtualCssBus *css_bus;
-
-    /* s390x ram size detection needs a 16bit multiplier + an increment. So
-       guests > 64GB can be specified in 2MB steps etc. */
-    while ((my_ram_size >> (20 + shift)) > 65535) {
-        shift++;
+    QemuOpts *opts = qemu_opts_find(qemu_find_opts("memory"), NULL);
+    ram_addr_t pad_size = 0;
+    ram_addr_t maxmem = qemu_opt_get_size(opts, "maxmem", my_ram_size);
+    ram_addr_t standby_mem_size = maxmem - my_ram_size;
+
+    /* The storage increment size is a multiple of 1M and is a power of 2.
+     * The number of storage increments must be MAX_STORAGE_INCREMENTS or fewer.
+     * The variable 'mhd->increment_size' is an exponent of 2 that can be
+     * used to calculate the size (in bytes) of an increment. */
+    mhd->increment_size = 20;
+    while ((my_ram_size >> mhd->increment_size) > MAX_STORAGE_INCREMENTS) {
+        mhd->increment_size++;
+    }
+    while ((standby_mem_size >> mhd->increment_size) > MAX_STORAGE_INCREMENTS) {
+        mhd->increment_size++;
     }
-    my_ram_size = my_ram_size >> (20 + shift) << (20 + shift);
+
+    /* The core and standby memory areas need to be aligned with
+     * the increment size.  In effect, this can cause the
+     * user-specified memory size to be rounded down to align
+     * with the nearest increment boundary. */
+    standby_mem_size = standby_mem_size >> mhd->increment_size
+                                        << mhd->increment_size;
+    my_ram_size = my_ram_size >> mhd->increment_size
+                              << mhd->increment_size;
 
     /* let's propagate the changed ram size into the global variable. */
     ram_size = my_ram_size;
@@ -111,11 +130,22 @@ static void ccw_init(MachineState *machine)
     /* register hypercalls */
     virtio_ccw_register_hcalls();
 
-    /* allocate RAM */
+    /* allocate RAM for core */
     memory_region_init_ram(ram, NULL, "s390.ram", my_ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(sysmem, 0, ram);
 
+    /* If the size of ram is not on a MEM_SECTION_SIZE boundary,
+       calculate the pad size necessary to force this boundary. */
+    if (standby_mem_size) {
+        if (my_ram_size % MEM_SECTION_SIZE) {
+            pad_size = MEM_SECTION_SIZE - my_ram_size % MEM_SECTION_SIZE;
+        }
+        my_ram_size += standby_mem_size + pad_size;
+        mhd->pad_size = pad_size;
+        mhd->standby_mem_size = standby_mem_size;
+    }
+
     /* allocate storage keys */
     storage_keys = g_malloc0(my_ram_size / TARGET_PAGE_SIZE);
 
diff --git a/hw/s390x/s390-virtio.c b/hw/s390x/s390-virtio.c
index 1a75a1cf81..4ca52b7190 100644
--- a/hw/s390x/s390-virtio.c
+++ b/hw/s390x/s390-virtio.c
@@ -230,18 +230,21 @@ static void s390_init(MachineState *machine)
     ram_addr_t my_ram_size = machine->ram_size;
     MemoryRegion *sysmem = get_system_memory();
     MemoryRegion *ram = g_new(MemoryRegion, 1);
-    int shift = 0;
+    int increment_size = 20;
     uint8_t *storage_keys;
     void *virtio_region;
     hwaddr virtio_region_len;
     hwaddr virtio_region_start;
 
-    /* s390x ram size detection needs a 16bit multiplier + an increment. So
-       guests > 64GB can be specified in 2MB steps etc. */
-    while ((my_ram_size >> (20 + shift)) > 65535) {
-        shift++;
+    /*
+     * The storage increment size is a multiple of 1M and is a power of 2.
+     * The number of storage increments must be MAX_STORAGE_INCREMENTS or
+     * fewer.
+     */
+    while ((my_ram_size >> increment_size) > MAX_STORAGE_INCREMENTS) {
+        increment_size++;
     }
-    my_ram_size = my_ram_size >> (20 + shift) << (20 + shift);
+    my_ram_size = my_ram_size >> increment_size << increment_size;
 
     /* let's propagate the changed ram size into the global variable. */
     ram_size = my_ram_size;
diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
index d8ddf35e58..02b3275132 100644
--- a/hw/s390x/sclp.c
+++ b/hw/s390x/sclp.c
@@ -16,7 +16,8 @@
 #include "sysemu/kvm.h"
 #include "exec/memory.h"
 #include "sysemu/sysemu.h"
-
+#include "exec/address-spaces.h"
+#include "qemu/config-file.h"
 #include "hw/s390x/sclp.h"
 #include "hw/s390x/event-facility.h"
 
@@ -33,10 +34,19 @@ static inline SCLPEventFacility *get_event_facility(void)
 static void read_SCP_info(SCCB *sccb)
 {
     ReadInfo *read_info = (ReadInfo *) sccb;
+    sclpMemoryHotplugDev *mhd = get_sclp_memory_hotplug_dev();
     CPUState *cpu;
-    int shift = 0;
     int cpu_count = 0;
     int i = 0;
+    int increment_size = 20;
+    int rnsize, rnmax;
+    QemuOpts *opts = qemu_opts_find(qemu_find_opts("memory"), NULL);
+    int slots = qemu_opt_get_number(opts, "slots", 0);
+    int max_avail_slots = s390_get_memslot_count(kvm_state);
+
+    if (slots > max_avail_slots) {
+        slots = max_avail_slots;
+    }
 
     CPU_FOREACH(cpu) {
         cpu_count++;
@@ -54,14 +64,235 @@ static void read_SCP_info(SCCB *sccb)
 
     read_info->facilities = cpu_to_be64(SCLP_HAS_CPU_INFO);
 
-    while ((ram_size >> (20 + shift)) > 65535) {
-        shift++;
+    /*
+     * The storage increment size is a multiple of 1M and is a power of 2.
+     * The number of storage increments must be MAX_STORAGE_INCREMENTS or fewer.
+     */
+    while ((ram_size >> increment_size) > MAX_STORAGE_INCREMENTS) {
+        increment_size++;
+    }
+    rnmax = ram_size >> increment_size;
+
+    /* Memory Hotplug is only supported for the ccw machine type */
+    if (mhd) {
+        while ((mhd->standby_mem_size >> increment_size) >
+               MAX_STORAGE_INCREMENTS) {
+            increment_size++;
+        }
+        assert(increment_size == mhd->increment_size);
+
+        mhd->standby_subregion_size = MEM_SECTION_SIZE;
+        /* Deduct the memory slot already used for core */
+        if (slots > 0) {
+            while ((mhd->standby_subregion_size * (slots - 1)
+                    < mhd->standby_mem_size)) {
+                mhd->standby_subregion_size = mhd->standby_subregion_size << 1;
+            }
+        }
+        /*
+         * Initialize mapping of guest standby memory sections indicating which
+         * are and are not online. Assume all standby memory begins offline.
+         */
+        if (mhd->standby_state_map == 0) {
+            if (mhd->standby_mem_size % mhd->standby_subregion_size) {
+                mhd->standby_state_map = g_malloc0((mhd->standby_mem_size /
+                                             mhd->standby_subregion_size + 1) *
+                                             (mhd->standby_subregion_size /
+                                             MEM_SECTION_SIZE));
+            } else {
+                mhd->standby_state_map = g_malloc0(mhd->standby_mem_size /
+                                                   MEM_SECTION_SIZE);
+            }
+        }
+        mhd->padded_ram_size = ram_size + mhd->pad_size;
+        mhd->rzm = 1 << mhd->increment_size;
+        rnmax = ((ram_size + mhd->standby_mem_size + mhd->pad_size)
+             >> mhd->increment_size);
+
+        read_info->facilities |= cpu_to_be64(SCLP_FC_ASSIGN_ATTACH_READ_STOR);
+    }
+
+    rnsize = 1 << (increment_size - 20);
+    if (rnsize <= 128) {
+        read_info->rnsize = rnsize;
+    } else {
+        read_info->rnsize = 0;
+        read_info->rnsize2 = cpu_to_be32(rnsize);
+    }
+
+    if (rnmax < 0x10000) {
+        read_info->rnmax = cpu_to_be16(rnmax);
+    } else {
+        read_info->rnmax = cpu_to_be16(0);
+        read_info->rnmax2 = cpu_to_be64(rnmax);
     }
-    read_info->rnmax = cpu_to_be16(ram_size >> (20 + shift));
-    read_info->rnsize = 1 << shift;
+
     sccb->h.response_code = cpu_to_be16(SCLP_RC_NORMAL_READ_COMPLETION);
 }
 
+static void read_storage_element0_info(SCCB *sccb)
+{
+    int i, assigned;
+    int subincrement_id = SCLP_STARTING_SUBINCREMENT_ID;
+    ReadStorageElementInfo *storage_info = (ReadStorageElementInfo *) sccb;
+    sclpMemoryHotplugDev *mhd = get_sclp_memory_hotplug_dev();
+
+    assert(mhd);
+
+    if ((ram_size >> mhd->increment_size) >= 0x10000) {
+        sccb->h.response_code = cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION);
+        return;
+    }
+
+    /* Return information regarding core memory */
+    storage_info->max_id = cpu_to_be16(mhd->standby_mem_size ? 1 : 0);
+    assigned = ram_size >> mhd->increment_size;
+    storage_info->assigned = cpu_to_be16(assigned);
+
+    for (i = 0; i < assigned; i++) {
+        storage_info->entries[i] = cpu_to_be32(subincrement_id);
+        subincrement_id += SCLP_INCREMENT_UNIT;
+    }
+    sccb->h.response_code = cpu_to_be16(SCLP_RC_NORMAL_READ_COMPLETION);
+}
+
+static void read_storage_element1_info(SCCB *sccb)
+{
+    ReadStorageElementInfo *storage_info = (ReadStorageElementInfo *) sccb;
+    sclpMemoryHotplugDev *mhd = get_sclp_memory_hotplug_dev();
+
+    assert(mhd);
+
+    if ((mhd->standby_mem_size >> mhd->increment_size) >= 0x10000) {
+        sccb->h.response_code = cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION);
+        return;
+    }
+
+    /* Return information regarding standby memory */
+    storage_info->max_id = cpu_to_be16(mhd->standby_mem_size ? 1 : 0);
+    storage_info->assigned = cpu_to_be16(mhd->standby_mem_size >>
+                                         mhd->increment_size);
+    storage_info->standby = cpu_to_be16(mhd->standby_mem_size >>
+                                        mhd->increment_size);
+    sccb->h.response_code = cpu_to_be16(SCLP_RC_STANDBY_READ_COMPLETION);
+}
+
+static void attach_storage_element(SCCB *sccb, uint16_t element)
+{
+    int i, assigned, subincrement_id;
+    AttachStorageElement *attach_info = (AttachStorageElement *) sccb;
+    sclpMemoryHotplugDev *mhd = get_sclp_memory_hotplug_dev();
+
+    assert(mhd);
+
+    if (element != 1) {
+        sccb->h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND);
+        return;
+    }
+
+    assigned = mhd->standby_mem_size >> mhd->increment_size;
+    attach_info->assigned = cpu_to_be16(assigned);
+    subincrement_id = ((ram_size >> mhd->increment_size) << 16)
+                      + SCLP_STARTING_SUBINCREMENT_ID;
+    for (i = 0; i < assigned; i++) {
+        attach_info->entries[i] = cpu_to_be32(subincrement_id);
+        subincrement_id += SCLP_INCREMENT_UNIT;
+    }
+    sccb->h.response_code = cpu_to_be16(SCLP_RC_NORMAL_COMPLETION);
+}
+
+static void assign_storage(SCCB *sccb)
+{
+    MemoryRegion *mr = NULL;
+    uint64_t this_subregion_size;
+    AssignStorage *assign_info = (AssignStorage *) sccb;
+    sclpMemoryHotplugDev *mhd = get_sclp_memory_hotplug_dev();
+    assert(mhd);
+    ram_addr_t assign_addr = (assign_info->rn - 1) * mhd->rzm;
+    MemoryRegion *sysmem = get_system_memory();
+
+    if ((assign_addr % MEM_SECTION_SIZE == 0) &&
+        (assign_addr >= mhd->padded_ram_size)) {
+        /* Re-use existing memory region if found */
+        mr = memory_region_find(sysmem, assign_addr, 1).mr;
+        if (!mr) {
+
+            MemoryRegion *standby_ram = g_new(MemoryRegion, 1);
+
+            /* offset to align to standby_subregion_size for allocation */
+            ram_addr_t offset = assign_addr -
+                                (assign_addr - mhd->padded_ram_size)
+                                % mhd->standby_subregion_size;
+
+            /* strlen("standby.ram") + 4 (Max of KVM_MEMORY_SLOTS) +  NULL */
+            char id[16];
+            snprintf(id, 16, "standby.ram%d",
+                     (int)((offset - mhd->padded_ram_size) /
+                     mhd->standby_subregion_size) + 1);
+
+            /* Allocate a subregion of the calculated standby_subregion_size */
+            if (offset + mhd->standby_subregion_size >
+                mhd->padded_ram_size + mhd->standby_mem_size) {
+                this_subregion_size = mhd->padded_ram_size +
+                  mhd->standby_mem_size - offset;
+            } else {
+                this_subregion_size = mhd->standby_subregion_size;
+            }
+
+            memory_region_init_ram(standby_ram, NULL, id, this_subregion_size);
+            vmstate_register_ram_global(standby_ram);
+            memory_region_add_subregion(sysmem, offset, standby_ram);
+        }
+        /* The specified subregion is no longer in standby */
+        mhd->standby_state_map[(assign_addr - mhd->padded_ram_size)
+                               / MEM_SECTION_SIZE] = 1;
+    }
+    sccb->h.response_code = cpu_to_be16(SCLP_RC_NORMAL_COMPLETION);
+}
+
+static void unassign_storage(SCCB *sccb)
+{
+    MemoryRegion *mr = NULL;
+    AssignStorage *assign_info = (AssignStorage *) sccb;
+    sclpMemoryHotplugDev *mhd = get_sclp_memory_hotplug_dev();
+    assert(mhd);
+    ram_addr_t unassign_addr = (assign_info->rn - 1) * mhd->rzm;
+    MemoryRegion *sysmem = get_system_memory();
+
+    /* if the addr is a multiple of 256 MB */
+    if ((unassign_addr % MEM_SECTION_SIZE == 0) &&
+        (unassign_addr >= mhd->padded_ram_size)) {
+        mhd->standby_state_map[(unassign_addr -
+                           mhd->padded_ram_size) / MEM_SECTION_SIZE] = 0;
+
+        /* find the specified memory region and destroy it */
+        mr = memory_region_find(sysmem, unassign_addr, 1).mr;
+        if (mr) {
+            int i;
+            int is_removable = 1;
+            ram_addr_t map_offset = (unassign_addr - mhd->padded_ram_size -
+                                     (unassign_addr - mhd->padded_ram_size)
+                                     % mhd->standby_subregion_size);
+            /* Mark all affected subregions as 'standby' once again */
+            for (i = 0;
+                 i < (mhd->standby_subregion_size / MEM_SECTION_SIZE);
+                 i++) {
+
+                if (mhd->standby_state_map[i + map_offset / MEM_SECTION_SIZE]) {
+                    is_removable = 0;
+                    break;
+                }
+            }
+            if (is_removable) {
+                memory_region_del_subregion(sysmem, mr);
+                object_unparent(OBJECT(mr));
+                g_free(mr);
+            }
+        }
+    }
+    sccb->h.response_code = cpu_to_be16(SCLP_RC_NORMAL_COMPLETION);
+}
+
 /* Provide information about the CPU */
 static void sclp_read_cpu_info(SCCB *sccb)
 {
@@ -103,6 +334,22 @@ static void sclp_execute(SCCB *sccb, uint32_t code)
     case SCLP_CMDW_READ_CPU_INFO:
         sclp_read_cpu_info(sccb);
         break;
+    case SCLP_READ_STORAGE_ELEMENT_INFO:
+        if (code & 0xff00) {
+            read_storage_element1_info(sccb);
+        } else {
+            read_storage_element0_info(sccb);
+        }
+        break;
+    case SCLP_ATTACH_STORAGE_ELEMENT:
+        attach_storage_element(sccb, (code & 0xff00) >> 8);
+        break;
+    case SCLP_ASSIGN_STORAGE:
+        assign_storage(sccb);
+        break;
+    case SCLP_UNASSIGN_STORAGE:
+        unassign_storage(sccb);
+        break;
     default:
         efc->command_handler(ef, sccb, code);
         break;
@@ -183,3 +430,33 @@ void s390_sclp_init(void)
                               OBJECT(dev), NULL);
     qdev_init_nofail(dev);
 }
+
+sclpMemoryHotplugDev *init_sclp_memory_hotplug_dev(void)
+{
+    DeviceState *dev;
+    dev = qdev_create(NULL, TYPE_SCLP_MEMORY_HOTPLUG_DEV);
+    object_property_add_child(qdev_get_machine(),
+                              TYPE_SCLP_MEMORY_HOTPLUG_DEV,
+                              OBJECT(dev), NULL);
+    qdev_init_nofail(dev);
+    return SCLP_MEMORY_HOTPLUG_DEV(object_resolve_path(
+                                   TYPE_SCLP_MEMORY_HOTPLUG_DEV, NULL));
+}
+
+sclpMemoryHotplugDev *get_sclp_memory_hotplug_dev(void)
+{
+    return SCLP_MEMORY_HOTPLUG_DEV(object_resolve_path(
+                                   TYPE_SCLP_MEMORY_HOTPLUG_DEV, NULL));
+}
+
+static TypeInfo sclp_memory_hotplug_dev_info = {
+    .name = TYPE_SCLP_MEMORY_HOTPLUG_DEV,
+    .parent = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(sclpMemoryHotplugDev),
+};
+
+static void register_types(void)
+{
+    type_register_static(&sclp_memory_hotplug_dev_info);
+}
+type_init(register_types);
diff --git a/include/hw/s390x/sclp.h b/include/hw/s390x/sclp.h
index 7ef16226df..5c435749e1 100644
--- a/include/hw/s390x/sclp.h
+++ b/include/hw/s390x/sclp.h
@@ -37,6 +37,7 @@
 #define SCLP_STARTING_SUBINCREMENT_ID           0x10001
 #define SCLP_INCREMENT_UNIT                     0x10000
 #define MAX_AVAIL_SLOTS                         32
+#define MAX_STORAGE_INCREMENTS                  1020
 
 /* CPU hotplug SCLP codes */
 #define SCLP_HAS_CPU_INFO                       0x0C00000000000000ULL
@@ -156,6 +157,23 @@ typedef struct SCCB {
     char data[SCCB_DATA_LEN];
  } QEMU_PACKED SCCB;
 
+typedef struct sclpMemoryHotplugDev sclpMemoryHotplugDev;
+
+#define TYPE_SCLP_MEMORY_HOTPLUG_DEV "sclp-memory-hotplug-dev"
+#define SCLP_MEMORY_HOTPLUG_DEV(obj) \
+  OBJECT_CHECK(sclpMemoryHotplugDev, (obj), TYPE_SCLP_MEMORY_HOTPLUG_DEV)
+
+struct sclpMemoryHotplugDev {
+    SysBusDevice parent;
+    ram_addr_t standby_mem_size;
+    ram_addr_t padded_ram_size;
+    ram_addr_t pad_size;
+    ram_addr_t standby_subregion_size;
+    ram_addr_t rzm;
+    int increment_size;
+    char *standby_state_map;
+};
+
 static inline int sccb_data_len(SCCB *sccb)
 {
     return be16_to_cpu(sccb->h.length) - sizeof(sccb->h);
@@ -163,6 +181,8 @@ static inline int sccb_data_len(SCCB *sccb)
 
 
 void s390_sclp_init(void);
+sclpMemoryHotplugDev *init_sclp_memory_hotplug_dev(void);
+sclpMemoryHotplugDev *get_sclp_memory_hotplug_dev(void);
 void sclp_service_interrupt(uint32_t sccb);
 void raise_irq_cpu_hotplug(void);
 
diff --git a/pc-bios/s390-ccw.img b/pc-bios/s390-ccw.img
index e3ea0d5664..44873ad181 100644
--- a/pc-bios/s390-ccw.img
+++ b/pc-bios/s390-ccw.img
diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c
index f1756796df..115d8bbac6 100644
--- a/pc-bios/s390-ccw/bootmap.c
+++ b/pc-bios/s390-ccw/bootmap.c
@@ -40,11 +40,6 @@ static void jump_to_IPL_2(void)
     ResetInfo *current = 0;
 
     void (*ipl)(void) = (void *) (uint64_t) current->ipl_continue;
-    debug_print_addr("set IPL addr to", ipl);
-
-    /* Ensure the guest output starts fresh */
-    sclp_print("\n");
-
     *current = save;
     ipl(); /* should not return */
 }
@@ -64,6 +59,11 @@ static void jump_to_IPL_code(uint64_t address)
     current->ipl_addr = (uint32_t) (uint64_t) &jump_to_IPL_2;
     current->ipl_continue = address & 0x7fffffff;
 
+    debug_print_int("set IPL addr to", current->ipl_continue);
+
+    /* Ensure the guest output starts fresh */
+    sclp_print("\n");
+
     /*
      * HACK ALERT.
      * We use the load normal reset to keep r15 unchanged. jump_to_IPL_2
@@ -93,11 +93,23 @@ static inline void verify_boot_info(BootInfo *bip)
                "Bad block size in zIPL section of the 1st record.");
 }
 
-static bool eckd_valid_address(BootMapPointer *p)
+static block_number_t eckd_block_num(BootMapPointer *p)
 {
+    const uint64_t sectors = virtio_get_sectors();
+    const uint64_t heads = virtio_get_heads();
     const uint64_t cylinder = p->eckd.cylinder
                             + ((p->eckd.head & 0xfff0) << 12);
     const uint64_t head = p->eckd.head & 0x000f;
+    const block_number_t block = sectors * heads * cylinder
+                               + sectors * head
+                               + p->eckd.sector
+                               - 1; /* block nr starts with zero */
+    return block;
+}
+
+static bool eckd_valid_address(BootMapPointer *p)
+{
+    const uint64_t head = p->eckd.head & 0x000f;
 
     if (head >= virtio_get_heads()
         ||  p->eckd.sector > virtio_get_sectors()
@@ -105,27 +117,14 @@ static bool eckd_valid_address(BootMapPointer *p)
         return false;
     }
 
-    if (!virtio_guessed_disk_nature() && cylinder >= virtio_get_cylinders()) {
+    if (!virtio_guessed_disk_nature() &&
+        eckd_block_num(p) >= virtio_get_blocks()) {
         return false;
     }
 
     return true;
 }
 
-static block_number_t eckd_block_num(BootMapPointer *p)
-{
-    const uint64_t sectors = virtio_get_sectors();
-    const uint64_t heads = virtio_get_heads();
-    const uint64_t cylinder = p->eckd.cylinder
-                            + ((p->eckd.head & 0xfff0) << 12);
-    const uint64_t head = p->eckd.head & 0x000f;
-    const block_number_t block = sectors * heads * cylinder
-                               + sectors * head
-                               + p->eckd.sector
-                               - 1; /* block nr starts with zero */
-    return block;
-}
-
 static block_number_t load_eckd_segments(block_number_t blk, uint64_t *address)
 {
     block_number_t block_nr;
@@ -223,7 +222,6 @@ static void ipl_eckd_cdl(void)
 
     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
     read_block(1, ipl2, "Cannot read IPL2 record at block 1");
-    IPL_assert(magic_match(ipl2, IPL2_MAGIC), "No IPL2 record");
 
     mbr = &ipl2->u.x.mbr;
     IPL_assert(magic_match(mbr, ZIPL_MAGIC), "No zIPL section in IPL2 record.");
@@ -247,12 +245,10 @@ static void ipl_eckd_cdl(void)
     /* no return */
 }
 
-static void ipl_eckd_ldl(ECKD_IPL_mode_t mode)
+static void print_eckd_ldl_msg(ECKD_IPL_mode_t mode)
 {
     LDL_VTOC *vlbl = (void *)sec; /* already read, 3rd block */
     char msg[4] = { '?', '.', '\n', '\0' };
-    block_number_t block_nr;
-    BootInfo *bip;
 
     sclp_print((mode == ECKD_CMS) ? "CMS" : "LDL");
     sclp_print(" version ");
@@ -272,12 +268,27 @@ static void ipl_eckd_ldl(ECKD_IPL_mode_t mode)
     }
     sclp_print(msg);
     print_volser(vlbl->volser);
+}
+
+static void ipl_eckd_ldl(ECKD_IPL_mode_t mode)
+{
+    block_number_t block_nr;
+    BootInfo *bip = (void *)(sec + 0x70); /* BootInfo is MBR for LDL */
+
+    if (mode != ECKD_LDL_UNLABELED) {
+        print_eckd_ldl_msg(mode);
+    }
 
     /* DO NOT read BootMap pointer (only one, xECKD) at block #2 */
 
     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
-    read_block(0, sec, "Cannot read block 0");
-    bip = (void *)(sec + 0x70); /* "boot info" is "eckd mbr" for LDL */
+    read_block(0, sec, "Cannot read block 0 to grab boot info.");
+    if (mode == ECKD_LDL_UNLABELED) {
+        if (!magic_match(bip->magic, ZIPL_MAGIC)) {
+            return; /* not applicable layout */
+        }
+        sclp_print("unlabeled LDL.\n");
+    }
     verify_boot_info(bip);
 
     block_nr = eckd_block_num((void *)&(bip->bp.ipl.bm_ptr.eckd.bptr));
@@ -285,17 +296,23 @@ static void ipl_eckd_ldl(ECKD_IPL_mode_t mode)
     /* no return */
 }
 
-static void ipl_eckd(ECKD_IPL_mode_t mode)
+static void print_eckd_msg(void)
 {
-    switch (mode) {
-    case ECKD_CDL:
-        ipl_eckd_cdl(); /* no return */
-    case ECKD_CMS:
-    case ECKD_LDL:
-        ipl_eckd_ldl(mode); /* no return */
-    default:
-        virtio_panic("\n! Unknown ECKD IPL mode !\n");
+    char msg[] = "Using ECKD scheme (block size *****), ";
+    char *p = &msg[34], *q = &msg[30];
+    int n = virtio_get_block_size();
+
+    /* Fill in the block size and show up the message */
+    if (n > 0 && n <= 99999) {
+        while (n) {
+            *p-- = '0' + (n % 10);
+            n /= 10;
+        }
+        while (p >= q) {
+            *p-- = ' ';
+        }
     }
+    sclp_print(msg);
 }
 
 /***********************************************************************
@@ -447,14 +464,13 @@ void zipl_load(void)
     }
 
     /* We have failed to follow the SCSI scheme, so */
-    sclp_print("Using ECKD scheme.\n");
     if (virtio_guessed_disk_nature()) {
         sclp_print("Using guessed DASD geometry.\n");
         virtio_assume_eckd();
     }
-
+    print_eckd_msg();
     if (magic_match(mbr->magic, IPL1_MAGIC)) {
-        ipl_eckd(ECKD_CDL); /* no return */
+        ipl_eckd_cdl(); /* no return */
     }
 
     /* LDL/CMS? */
@@ -462,11 +478,18 @@ void zipl_load(void)
     read_block(2, vlbl, "Cannot read block 2");
 
     if (magic_match(vlbl->magic, CMS1_MAGIC)) {
-        ipl_eckd(ECKD_CMS); /* no return */
+        ipl_eckd_ldl(ECKD_CMS); /* no return */
     }
     if (magic_match(vlbl->magic, LNX1_MAGIC)) {
-        ipl_eckd(ECKD_LDL); /* no return */
+        ipl_eckd_ldl(ECKD_LDL); /* no return */
     }
 
-    virtio_panic("\n* invalid MBR magic *\n");
+    ipl_eckd_ldl(ECKD_LDL_UNLABELED); /* it still may return */
+    /*
+     * Ok, it is not a LDL by any means.
+     * It still might be a CDL with zero record keys for IPL1 and IPL2
+     */
+    ipl_eckd_cdl();
+
+    virtio_panic("\n* this can never happen *\n");
 }
diff --git a/pc-bios/s390-ccw/bootmap.h b/pc-bios/s390-ccw/bootmap.h
index 30ef22fe61..6a4823d544 100644
--- a/pc-bios/s390-ccw/bootmap.h
+++ b/pc-bios/s390-ccw/bootmap.h
@@ -257,9 +257,9 @@ typedef struct IplVolumeLabel {
 
 typedef enum {
     ECKD_NO_IPL,
-    ECKD_CDL,
     ECKD_CMS,
     ECKD_LDL,
+    ECKD_LDL_UNLABELED,
 } ECKD_IPL_mode_t;
 
 /* utility code below */
diff --git a/pc-bios/s390-ccw/virtio.c b/pc-bios/s390-ccw/virtio.c
index 31b23b086c..c0540d1cd4 100644
--- a/pc-bios/s390-ccw/virtio.c
+++ b/pc-bios/s390-ccw/virtio.c
@@ -275,12 +275,14 @@ void virtio_assume_scsi(void)
 {
     guessed_disk_nature = true;
     blk_cfg.blk_size = 512;
+    blk_cfg.physical_block_exp = 0;
 }
 
 void virtio_assume_eckd(void)
 {
     guessed_disk_nature = true;
     blk_cfg.blk_size = 4096;
+    blk_cfg.physical_block_exp = 0;
 
     /* this must be here to calculate code segment position */
     blk_cfg.geometry.heads = 15;
@@ -290,36 +292,52 @@ void virtio_assume_eckd(void)
 bool virtio_disk_is_scsi(void)
 {
     if (guessed_disk_nature) {
-        return (blk_cfg.blk_size  == 512);
+        return (virtio_get_block_size()  == 512);
     }
     return (blk_cfg.geometry.heads == 255)
         && (blk_cfg.geometry.sectors == 63)
-        && (blk_cfg.blk_size  == 512);
+        && (virtio_get_block_size()  == 512);
+}
+
+/*
+ * Other supported value pairs, if any, would need to be added here.
+ * Note: head count is always 15.
+ */
+static inline u8 virtio_eckd_sectors_for_block_size(int size)
+{
+    switch (size) {
+    case 512:
+        return 49;
+    case 1024:
+        return 33;
+    case 2048:
+        return 21;
+    case 4096:
+        return 12;
+    }
+    return 0;
 }
 
 bool virtio_disk_is_eckd(void)
 {
+    const int block_size = virtio_get_block_size();
+
     if (guessed_disk_nature) {
-        return (blk_cfg.blk_size  == 4096);
+        return (block_size  == 4096);
     }
     return (blk_cfg.geometry.heads == 15)
-        && (blk_cfg.geometry.sectors == 12)
-        && (blk_cfg.blk_size  == 4096);
+        && (blk_cfg.geometry.sectors ==
+            virtio_eckd_sectors_for_block_size(block_size));
 }
 
 bool virtio_ipl_disk_is_valid(void)
 {
-    return blk_cfg.blk_size && (virtio_disk_is_scsi() || virtio_disk_is_eckd());
+    return virtio_disk_is_scsi() || virtio_disk_is_eckd();
 }
 
 int virtio_get_block_size(void)
 {
-    return blk_cfg.blk_size;
-}
-
-uint16_t virtio_get_cylinders(void)
-{
-    return blk_cfg.geometry.cylinders;
+    return blk_cfg.blk_size << blk_cfg.physical_block_exp;
 }
 
 uint8_t virtio_get_heads(void)
@@ -332,6 +350,12 @@ uint8_t virtio_get_sectors(void)
     return blk_cfg.geometry.sectors;
 }
 
+uint64_t virtio_get_blocks(void)
+{
+    return blk_cfg.capacity /
+           (virtio_get_block_size() / VIRTIO_SECTOR_SIZE);
+}
+
 void virtio_setup_block(struct subchannel_id schid)
 {
     struct vq_info_block info;
diff --git a/pc-bios/s390-ccw/virtio.h b/pc-bios/s390-ccw/virtio.h
index f1fb1b08fa..c23466b8db 100644
--- a/pc-bios/s390-ccw/virtio.h
+++ b/pc-bios/s390-ccw/virtio.h
@@ -192,9 +192,9 @@ extern bool virtio_disk_is_scsi(void);
 extern bool virtio_disk_is_eckd(void);
 extern bool virtio_ipl_disk_is_valid(void);
 extern int virtio_get_block_size(void);
-extern uint16_t virtio_get_cylinders(void);
 extern uint8_t virtio_get_heads(void);
 extern uint8_t virtio_get_sectors(void);
+extern uint64_t virtio_get_blocks(void);
 extern int virtio_read_many(ulong sector, void *load_addr, int sec_num);
 
 #define VIRTIO_SECTOR_SIZE 512
diff --git a/qemu-options.hx b/qemu-options.hx
index 5479cf54f4..ecd0e34269 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -225,7 +225,8 @@ DEF("m", HAS_ARG, QEMU_OPTION_m,
     "                size: initial amount of guest memory (default: "
     stringify(DEFAULT_RAM_SIZE) "MiB)\n"
     "                slots: number of hotplug slots (default: none)\n"
-    "                maxmem: maximum amount of guest memory (default: none)\n",
+    "                maxmem: maximum amount of guest memory (default: none)\n"
+    "NOTE: Some architectures might enforce a specific granularity\n",
     QEMU_ARCH_ALL)
 STEXI
 @item -m [size=]@var{megs}
diff --git a/target-s390x/cpu-qom.h b/target-s390x/cpu-qom.h
index f9c96d13a9..80dd74142c 100644
--- a/target-s390x/cpu-qom.h
+++ b/target-s390x/cpu-qom.h
@@ -89,5 +89,6 @@ hwaddr s390_cpu_get_phys_page_debug(CPUState *cpu, vaddr addr);
 hwaddr s390_cpu_get_phys_addr_debug(CPUState *cpu, vaddr addr);
 int s390_cpu_gdb_read_register(CPUState *cpu, uint8_t *buf, int reg);
 int s390_cpu_gdb_write_register(CPUState *cpu, uint8_t *buf, int reg);
+void s390_cpu_gdb_init(CPUState *cs);
 
 #endif
diff --git a/target-s390x/cpu.c b/target-s390x/cpu.c
index c3082b73c5..97a92168a8 100644
--- a/target-s390x/cpu.c
+++ b/target-s390x/cpu.c
@@ -165,7 +165,7 @@ static void s390_cpu_machine_reset_cb(void *opaque)
 {
     S390CPU *cpu = opaque;
 
-    cpu_reset(CPU(cpu));
+    run_on_cpu(CPU(cpu), s390_do_cpu_full_reset, CPU(cpu));
 }
 #endif
 
@@ -174,8 +174,13 @@ static void s390_cpu_realizefn(DeviceState *dev, Error **errp)
     CPUState *cs = CPU(dev);
     S390CPUClass *scc = S390_CPU_GET_CLASS(dev);
 
+    s390_cpu_gdb_init(cs);
     qemu_init_vcpu(cs);
+#if !defined(CONFIG_USER_ONLY)
+    run_on_cpu(cs, s390_do_cpu_full_reset, cs);
+#else
     cpu_reset(cs);
+#endif
 
     scc->parent_realize(dev, errp);
 }
@@ -259,7 +264,8 @@ static void s390_cpu_class_init(ObjectClass *oc, void *data)
     cc->write_elf64_qemunote = s390_cpu_write_elf64_qemunote;
 #endif
     dc->vmsd = &vmstate_s390_cpu;
-    cc->gdb_num_core_regs = S390_NUM_REGS;
+    cc->gdb_num_core_regs = S390_NUM_CORE_REGS;
+    cc->gdb_core_xml_file = "s390x-core64.xml";
 }
 
 static const TypeInfo s390_cpu_type_info = {
diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
index b13761d925..62940c398a 100644
--- a/target-s390x/cpu.h
+++ b/target-s390x/cpu.h
@@ -353,6 +353,21 @@ static inline hwaddr decode_basedisp_s(CPUS390XState *env, uint32_t ipb)
 /* Base/displacement are at the same locations. */
 #define decode_basedisp_rs decode_basedisp_s
 
+/* helper functions for run_on_cpu() */
+static inline void s390_do_cpu_reset(void *arg)
+{
+    CPUState *cs = arg;
+    S390CPUClass *scc = S390_CPU_GET_CLASS(cs);
+
+    scc->cpu_reset(cs);
+}
+static inline void s390_do_cpu_full_reset(void *arg)
+{
+    CPUState *cs = arg;
+
+    cpu_reset(cs);
+}
+
 void s390x_tod_timer(void *opaque);
 void s390x_cpu_timer(void *opaque);
 
@@ -551,44 +566,8 @@ void s390_cpu_list(FILE *f, fprintf_function cpu_fprintf);
 #define S390_R13_REGNUM 15
 #define S390_R14_REGNUM 16
 #define S390_R15_REGNUM 17
-/* Access Registers.  */
-#define S390_A0_REGNUM 18
-#define S390_A1_REGNUM 19
-#define S390_A2_REGNUM 20
-#define S390_A3_REGNUM 21
-#define S390_A4_REGNUM 22
-#define S390_A5_REGNUM 23
-#define S390_A6_REGNUM 24
-#define S390_A7_REGNUM 25
-#define S390_A8_REGNUM 26
-#define S390_A9_REGNUM 27
-#define S390_A10_REGNUM 28
-#define S390_A11_REGNUM 29
-#define S390_A12_REGNUM 30
-#define S390_A13_REGNUM 31
-#define S390_A14_REGNUM 32
-#define S390_A15_REGNUM 33
-/* Floating Point Control Word.  */
-#define S390_FPC_REGNUM 34
-/* Floating Point Registers.  */
-#define S390_F0_REGNUM 35
-#define S390_F1_REGNUM 36
-#define S390_F2_REGNUM 37
-#define S390_F3_REGNUM 38
-#define S390_F4_REGNUM 39
-#define S390_F5_REGNUM 40
-#define S390_F6_REGNUM 41
-#define S390_F7_REGNUM 42
-#define S390_F8_REGNUM 43
-#define S390_F9_REGNUM 44
-#define S390_F10_REGNUM 45
-#define S390_F11_REGNUM 46
-#define S390_F12_REGNUM 47
-#define S390_F13_REGNUM 48
-#define S390_F14_REGNUM 49
-#define S390_F15_REGNUM 50
-/* Total.  */
-#define S390_NUM_REGS 51
+/* Total Core Registers. */
+#define S390_NUM_CORE_REGS 18
 
 /* CC optimization */
 
@@ -1045,6 +1024,10 @@ static inline void cpu_inject_crw_mchk(S390CPU *cpu)
     cpu_interrupt(CPU(cpu), CPU_INTERRUPT_HARD);
 }
 
+/* from s390-virtio-ccw */
+#define MEM_SECTION_SIZE             0x10000000UL
+#define MAX_AVAIL_SLOTS              32
+
 /* fpu_helper.c */
 uint32_t set_cc_nz_f32(float32 v);
 uint32_t set_cc_nz_f64(float64 v);
@@ -1067,6 +1050,7 @@ void kvm_s390_enable_css_support(S390CPU *cpu);
 int kvm_s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch,
                                     int vq, bool assign);
 int kvm_s390_cpu_restart(S390CPU *cpu);
+int kvm_s390_get_memslot_count(KVMState *s);
 void kvm_s390_clear_cmma_callback(void *opaque);
 #else
 static inline void kvm_s390_io_interrupt(uint16_t subchannel_id,
@@ -1094,6 +1078,10 @@ static inline int kvm_s390_cpu_restart(S390CPU *cpu)
 static inline void kvm_s390_clear_cmma_callback(void *opaque)
 {
 }
+static inline int kvm_s390_get_memslot_count(KVMState *s)
+{
+  return MAX_AVAIL_SLOTS;
+}
 #endif
 
 static inline void cmma_reset(S390CPU *cpu)
@@ -1112,6 +1100,15 @@ static inline int s390_cpu_restart(S390CPU *cpu)
     return -ENOSYS;
 }
 
+static inline int s390_get_memslot_count(KVMState *s)
+{
+    if (kvm_enabled()) {
+        return kvm_s390_get_memslot_count(s);
+    } else {
+        return MAX_AVAIL_SLOTS;
+    }
+}
+
 void s390_io_interrupt(uint16_t subchannel_id, uint16_t subchannel_nr,
                        uint32_t io_int_parm, uint32_t io_int_word);
 void s390_crw_mchk(void);
diff --git a/target-s390x/gdbstub.c b/target-s390x/gdbstub.c
index a129742e2f..8945f0271d 100644
--- a/target-s390x/gdbstub.c
+++ b/target-s390x/gdbstub.c
@@ -31,21 +31,18 @@ int s390_cpu_gdb_read_register(CPUState *cs, uint8_t *mem_buf, int n)
 
     switch (n) {
     case S390_PSWM_REGNUM:
-        cc_op = calc_cc(env, env->cc_op, env->cc_src, env->cc_dst, env->cc_vr);
-        val = deposit64(env->psw.mask, 44, 2, cc_op);
-        return gdb_get_regl(mem_buf, val);
+        if (tcg_enabled()) {
+            cc_op = calc_cc(env, env->cc_op, env->cc_src, env->cc_dst,
+                            env->cc_vr);
+            val = deposit64(env->psw.mask, 44, 2, cc_op);
+            return gdb_get_regl(mem_buf, val);
+        }
+        return gdb_get_regl(mem_buf, env->psw.mask);
     case S390_PSWA_REGNUM:
         return gdb_get_regl(mem_buf, env->psw.addr);
     case S390_R0_REGNUM ... S390_R15_REGNUM:
-        return gdb_get_regl(mem_buf, env->regs[n-S390_R0_REGNUM]);
-    case S390_A0_REGNUM ... S390_A15_REGNUM:
-        return gdb_get_reg32(mem_buf, env->aregs[n-S390_A0_REGNUM]);
-    case S390_FPC_REGNUM:
-        return gdb_get_reg32(mem_buf, env->fpc);
-    case S390_F0_REGNUM ... S390_F15_REGNUM:
-        return gdb_get_reg64(mem_buf, env->fregs[n-S390_F0_REGNUM].ll);
+        return gdb_get_regl(mem_buf, env->regs[n - S390_R0_REGNUM]);
     }
-
     return 0;
 }
 
@@ -53,36 +50,94 @@ int s390_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
 {
     S390CPU *cpu = S390_CPU(cs);
     CPUS390XState *env = &cpu->env;
-    target_ulong tmpl;
-    uint32_t tmp32;
-    int r = 8;
-    tmpl = ldtul_p(mem_buf);
-    tmp32 = ldl_p(mem_buf);
+    target_ulong tmpl = ldtul_p(mem_buf);
 
     switch (n) {
     case S390_PSWM_REGNUM:
         env->psw.mask = tmpl;
-        env->cc_op = extract64(tmpl, 44, 2);
+        if (tcg_enabled()) {
+            env->cc_op = extract64(tmpl, 44, 2);
+        }
         break;
     case S390_PSWA_REGNUM:
         env->psw.addr = tmpl;
         break;
     case S390_R0_REGNUM ... S390_R15_REGNUM:
-        env->regs[n-S390_R0_REGNUM] = tmpl;
+        env->regs[n - S390_R0_REGNUM] = tmpl;
         break;
+    default:
+        return 0;
+    }
+    return 8;
+}
+
+/* the values represent the positions in s390-acr.xml */
+#define S390_A0_REGNUM 0
+#define S390_A15_REGNUM 15
+/* total number of registers in s390-acr.xml */
+#define S390_NUM_AC_REGS 16
+
+static int cpu_read_ac_reg(CPUS390XState *env, uint8_t *mem_buf, int n)
+{
+    switch (n) {
     case S390_A0_REGNUM ... S390_A15_REGNUM:
-        env->aregs[n-S390_A0_REGNUM] = tmp32;
-        r = 4;
-        break;
+        return gdb_get_reg32(mem_buf, env->aregs[n]);
+    default:
+        return 0;
+    }
+}
+
+static int cpu_write_ac_reg(CPUS390XState *env, uint8_t *mem_buf, int n)
+{
+    switch (n) {
+    case S390_A0_REGNUM ... S390_A15_REGNUM:
+        env->aregs[n] = ldl_p(mem_buf);
+        return 4;
+    default:
+        return 0;
+    }
+}
+
+/* the values represent the positions in s390-fpr.xml */
+#define S390_FPC_REGNUM 0
+#define S390_F0_REGNUM 1
+#define S390_F15_REGNUM 16
+/* total number of registers in s390-fpr.xml */
+#define S390_NUM_FP_REGS 17
+
+static int cpu_read_fp_reg(CPUS390XState *env, uint8_t *mem_buf, int n)
+{
+    switch (n) {
     case S390_FPC_REGNUM:
-        env->fpc = tmp32;
-        r = 4;
-        break;
+        return gdb_get_reg32(mem_buf, env->fpc);
     case S390_F0_REGNUM ... S390_F15_REGNUM:
-        env->fregs[n-S390_F0_REGNUM].ll = tmpl;
-        break;
+        return gdb_get_reg64(mem_buf, env->fregs[n - S390_F0_REGNUM].ll);
     default:
         return 0;
     }
-    return r;
+}
+
+static int cpu_write_fp_reg(CPUS390XState *env, uint8_t *mem_buf, int n)
+{
+    switch (n) {
+    case S390_FPC_REGNUM:
+        env->fpc = ldl_p(mem_buf);
+        return 4;
+    case S390_F0_REGNUM ... S390_F15_REGNUM:
+        env->fregs[n - S390_F0_REGNUM].ll = ldtul_p(mem_buf);
+        return 8;
+    default:
+        return 0;
+    }
+}
+
+void s390_cpu_gdb_init(CPUState *cs)
+{
+    gdb_register_coprocessor(cs, cpu_read_ac_reg,
+                             cpu_write_ac_reg,
+                             S390_NUM_AC_REGS, "s390-acr.xml", 0);
+
+    gdb_register_coprocessor(cs, cpu_read_fp_reg,
+                             cpu_write_fp_reg,
+                             S390_NUM_FP_REGS, "s390-fpr.xml", 0);
 }
diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index a32d91aa01..a85a480c6a 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -916,23 +916,30 @@ static int handle_diag(S390CPU *cpu, struct kvm_run *run, uint32_t ipb)
     return r;
 }
 
-static int kvm_s390_cpu_start(S390CPU *cpu)
+static void sigp_cpu_start(void *arg)
 {
+    CPUState *cs = arg;
+    S390CPU *cpu = S390_CPU(cs);
+
     s390_add_running_cpu(cpu);
-    qemu_cpu_kick(CPU(cpu));
     DPRINTF("DONE: KVM cpu start: %p\n", &cpu->env);
-    return 0;
 }
 
-int kvm_s390_cpu_restart(S390CPU *cpu)
+static void sigp_cpu_restart(void *arg)
 {
+    CPUState *cs = arg;
+    S390CPU *cpu = S390_CPU(cs);
     struct kvm_s390_irq irq = {
         .type = KVM_S390_RESTART,
     };
 
     kvm_s390_vcpu_interrupt(cpu, &irq);
     s390_add_running_cpu(cpu);
-    qemu_cpu_kick(CPU(cpu));
+}
+
+int kvm_s390_cpu_restart(S390CPU *cpu)
+{
+    run_on_cpu(CPU(cpu), sigp_cpu_restart, CPU(cpu));
     DPRINTF("DONE: KVM cpu restart: %p\n", &cpu->env);
     return 0;
 }
@@ -980,10 +987,12 @@ static int handle_sigp(S390CPU *cpu, struct kvm_run *run, uint8_t ipa1)
 
     switch (order_code) {
     case SIGP_START:
-        cc = kvm_s390_cpu_start(target_cpu);
+        run_on_cpu(CPU(target_cpu), sigp_cpu_start, CPU(target_cpu));
+        cc = 0;
         break;
     case SIGP_RESTART:
-        cc = kvm_s390_cpu_restart(target_cpu);
+        run_on_cpu(CPU(target_cpu), sigp_cpu_restart, CPU(target_cpu));
+        cc = 0;
         break;
     case SIGP_SET_ARCH:
         *statusreg &= 0xffffffff00000000UL;
@@ -1306,3 +1315,8 @@ int kvm_s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch,
     }
     return kvm_vm_ioctl(kvm_state, KVM_IOEVENTFD, &kick);
 }
+
+int kvm_s390_get_memslot_count(KVMState *s)
+{
+    return kvm_check_extension(s, KVM_CAP_NR_MEMSLOTS);
+}
diff --git a/target-s390x/misc_helper.c b/target-s390x/misc_helper.c
index 0b625826ef..ef9758a96a 100644
--- a/target-s390x/misc_helper.c
+++ b/target-s390x/misc_helper.c
@@ -114,33 +114,16 @@ uint32_t HELPER(servc)(CPUS390XState *env, uint64_t r1, uint64_t r2)
 }
 
 #ifndef CONFIG_USER_ONLY
-static void cpu_reset_all(void)
-{
-    CPUState *cs;
-    S390CPUClass *scc;
-
-    CPU_FOREACH(cs) {
-        scc = S390_CPU_GET_CLASS(cs);
-        scc->cpu_reset(cs);
-    }
-}
-
-static void cpu_full_reset_all(void)
-{
-    CPUState *cpu;
-
-    CPU_FOREACH(cpu) {
-        cpu_reset(cpu);
-    }
-}
-
 static int modified_clear_reset(S390CPU *cpu)
 {
     S390CPUClass *scc = S390_CPU_GET_CLASS(cpu);
+    CPUState *t;
 
     pause_all_vcpus();
     cpu_synchronize_all_states();
-    cpu_full_reset_all();
+    CPU_FOREACH(t) {
+        run_on_cpu(t, s390_do_cpu_full_reset, t);
+    }
     cmma_reset(cpu);
     io_subsystem_reset();
     scc->load_normal(CPU(cpu));
@@ -152,10 +135,13 @@ static int modified_clear_reset(S390CPU *cpu)
 static int load_normal_reset(S390CPU *cpu)
 {
     S390CPUClass *scc = S390_CPU_GET_CLASS(cpu);
+    CPUState *t;
 
     pause_all_vcpus();
     cpu_synchronize_all_states();
-    cpu_reset_all();
+    CPU_FOREACH(t) {
+        run_on_cpu(t, s390_do_cpu_reset, t);
+    }
     cmma_reset(cpu);
     io_subsystem_reset();
     scc->initial_cpu_reset(CPU(cpu));