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qemu/hw/s390x/sclp.c
David Hildenbrand 732bdd383e s390/sclp: temporarily fix unassignment/reassignment of memory subregions 
Commit 374f2981d1 ("memory: protect current_map by RCU") broke
unassignment of standby memory on s390x. Looks like that the new
parallelism allows races with our (semi broken) memory hotplug code. The
flatview_unref() can now be executed after our unparenting. Therefore
memory_region_unref() tries to unreference the MemoryRegion itself instead
of the parent.

In theory, MemoryRegions are now bound to separate devices that control
their lifetime. We don't have this yet, so we really want to control their
lifetime manually.

This patch fixes it temporarily, until we have a proper rework. The only
drawback is that they won't pop up in "info qom-tree", but that's better
than qemu crashes.

We have to release the reference to a memory region after a
memory_region_find, as it automatically takes a reference. As we're now
able to reassign memory, the MemoryRegion is in fact deleted (otherwise
vmstate_register_ram() would complain).

Reviewed-by: Matthew Rosato <mjrosato@linux.vnet.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
2015-09-07 16:10:43 +02:00

485 lines
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/*
* SCLP Support
*
* Copyright IBM, Corp. 2012
*
* Authors:
* Christian Borntraeger <borntraeger@de.ibm.com>
* Heinz Graalfs <graalfs@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or (at your
* option) any later version. See the COPYING file in the top-level directory.
*
*/
#include "cpu.h"
#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"
#include "hw/s390x/s390-pci-bus.h"
static inline SCLPEventFacility *get_event_facility(void)
{
ObjectProperty *op = object_property_find(qdev_get_machine(),
TYPE_SCLP_EVENT_FACILITY,
NULL);
assert(op);
return op->opaque;
}
/* Provide information about the configuration, CPUs and storage */
static void read_SCP_info(SCCB *sccb)
{
ReadInfo *read_info = (ReadInfo *) sccb;
sclpMemoryHotplugDev *mhd = get_sclp_memory_hotplug_dev();
CPUState *cpu;
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++;
}
/* CPU information */
read_info->entries_cpu = cpu_to_be16(cpu_count);
read_info->offset_cpu = cpu_to_be16(offsetof(ReadInfo, entries));
read_info->highest_cpu = cpu_to_be16(max_cpus);
for (i = 0; i < cpu_count; i++) {
read_info->entries[i].address = i;
read_info->entries[i].type = 0;
}
read_info->facilities = cpu_to_be64(SCLP_HAS_CPU_INFO |
SCLP_HAS_PCI_RECONFIG);
/*
* 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);
}
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;
memory_region_unref(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, &error_abort);
/* This is a hack to make memory hotunplug work again. Once we have
* subdevices, we have to unparent them when unassigning memory,
* instead of doing it via the ref count of the MemoryRegion. */
object_ref(OBJECT(standby_ram));
object_unparent(OBJECT(standby_ram));
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;
memory_region_unref(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_unref(OBJECT(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)
{
ReadCpuInfo *cpu_info = (ReadCpuInfo *) sccb;
CPUState *cpu;
int cpu_count = 0;
int i = 0;
CPU_FOREACH(cpu) {
cpu_count++;
}
cpu_info->nr_configured = cpu_to_be16(cpu_count);
cpu_info->offset_configured = cpu_to_be16(offsetof(ReadCpuInfo, entries));
cpu_info->nr_standby = cpu_to_be16(0);
/* The standby offset is 16-byte for each CPU */
cpu_info->offset_standby = cpu_to_be16(cpu_info->offset_configured
+ cpu_info->nr_configured*sizeof(CPUEntry));
for (i = 0; i < cpu_count; i++) {
cpu_info->entries[i].address = i;
cpu_info->entries[i].type = 0;
}
sccb->h.response_code = cpu_to_be16(SCLP_RC_NORMAL_READ_COMPLETION);
}
static void sclp_execute(SCCB *sccb, uint32_t code)
{
SCLPEventFacility *ef = get_event_facility();
SCLPEventFacilityClass *efc = EVENT_FACILITY_GET_CLASS(ef);
switch (code & SCLP_CMD_CODE_MASK) {
case SCLP_CMDW_READ_SCP_INFO:
case SCLP_CMDW_READ_SCP_INFO_FORCED:
read_SCP_info(sccb);
break;
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;
case SCLP_CMDW_CONFIGURE_PCI:
s390_pci_sclp_configure(1, sccb);
break;
case SCLP_CMDW_DECONFIGURE_PCI:
s390_pci_sclp_configure(0, sccb);
break;
default:
efc->command_handler(ef, sccb, code);
break;
}
}
int sclp_service_call(CPUS390XState *env, uint64_t sccb, uint32_t code)
{
int r = 0;
SCCB work_sccb;
hwaddr sccb_len = sizeof(SCCB);
/* first some basic checks on program checks */
if (env->psw.mask & PSW_MASK_PSTATE) {
r = -PGM_PRIVILEGED;
goto out;
}
if (cpu_physical_memory_is_io(sccb)) {
r = -PGM_ADDRESSING;
goto out;
}
if ((sccb & ~0x1fffUL) == 0 || (sccb & ~0x1fffUL) == env->psa
|| (sccb & ~0x7ffffff8UL) != 0) {
r = -PGM_SPECIFICATION;
goto out;
}
/*
* we want to work on a private copy of the sccb, to prevent guests
* from playing dirty tricks by modifying the memory content after
* the host has checked the values
*/
cpu_physical_memory_read(sccb, &work_sccb, sccb_len);
/* Valid sccb sizes */
if (be16_to_cpu(work_sccb.h.length) < sizeof(SCCBHeader) ||
be16_to_cpu(work_sccb.h.length) > SCCB_SIZE) {
r = -PGM_SPECIFICATION;
goto out;
}
sclp_execute((SCCB *)&work_sccb, code);
cpu_physical_memory_write(sccb, &work_sccb,
be16_to_cpu(work_sccb.h.length));
sclp_service_interrupt(sccb);
out:
return r;
}
void sclp_service_interrupt(uint32_t sccb)
{
SCLPEventFacility *ef = get_event_facility();
SCLPEventFacilityClass *efc = EVENT_FACILITY_GET_CLASS(ef);
uint32_t param = sccb & ~3;
/* Indicate whether an event is still pending */
param |= efc->event_pending(ef) ? 1 : 0;
if (!param) {
/* No need to send an interrupt, there's nothing to be notified about */
return;
}
s390_sclp_extint(param);
}
/* qemu object creation and initialization functions */
void s390_sclp_init(void)
{
DeviceState *dev = qdev_create(NULL, TYPE_SCLP_EVENT_FACILITY);
object_property_add_child(qdev_get_machine(), TYPE_SCLP_EVENT_FACILITY,
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 void sclp_memory_hotplug_dev_class_init(ObjectClass *klass,
void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
set_bit(DEVICE_CATEGORY_MISC, dc->categories);
}
static TypeInfo sclp_memory_hotplug_dev_info = {
.name = TYPE_SCLP_MEMORY_HOTPLUG_DEV,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(sclpMemoryHotplugDev),
.class_init = sclp_memory_hotplug_dev_class_init,
};
static void register_types(void)
{
type_register_static(&sclp_memory_hotplug_dev_info);
}
type_init(register_types);
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