blob: a1b1af26bc4f665ef7bf408a27f2e0b140cdf9c6 [file] [log] [blame]
/*
* Memory Device Interface
*
* Copyright ProfitBricks GmbH 2012
* Copyright (C) 2014 Red Hat Inc
* Copyright (c) 2018 Red Hat Inc
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qemu/error-report.h"
#include "hw/mem/memory-device.h"
#include "qapi/error.h"
#include "hw/boards.h"
#include "qemu/range.h"
#include "hw/virtio/vhost.h"
#include "sysemu/kvm.h"
#include "exec/address-spaces.h"
#include "trace.h"
static bool memory_device_is_empty(const MemoryDeviceState *md)
{
const MemoryDeviceClass *mdc = MEMORY_DEVICE_GET_CLASS(md);
Error *local_err = NULL;
MemoryRegion *mr;
/* dropping const here is fine as we don't touch the memory region */
mr = mdc->get_memory_region((MemoryDeviceState *)md, &local_err);
if (local_err) {
/* Not empty, we'll report errors later when containing the MR again. */
error_free(local_err);
return false;
}
return !mr;
}
static gint memory_device_addr_sort(gconstpointer a, gconstpointer b)
{
const MemoryDeviceState *md_a = MEMORY_DEVICE(a);
const MemoryDeviceState *md_b = MEMORY_DEVICE(b);
const MemoryDeviceClass *mdc_a = MEMORY_DEVICE_GET_CLASS(a);
const MemoryDeviceClass *mdc_b = MEMORY_DEVICE_GET_CLASS(b);
const uint64_t addr_a = mdc_a->get_addr(md_a);
const uint64_t addr_b = mdc_b->get_addr(md_b);
if (addr_a > addr_b) {
return 1;
} else if (addr_a < addr_b) {
return -1;
}
return 0;
}
static int memory_device_build_list(Object *obj, void *opaque)
{
GSList **list = opaque;
if (object_dynamic_cast(obj, TYPE_MEMORY_DEVICE)) {
DeviceState *dev = DEVICE(obj);
if (dev->realized) { /* only realized memory devices matter */
*list = g_slist_insert_sorted(*list, dev, memory_device_addr_sort);
}
}
object_child_foreach(obj, memory_device_build_list, opaque);
return 0;
}
static unsigned int memory_device_get_memslots(MemoryDeviceState *md)
{
const MemoryDeviceClass *mdc = MEMORY_DEVICE_GET_CLASS(md);
if (mdc->get_memslots) {
return mdc->get_memslots(md);
}
return 1;
}
/*
* Memslots that are reserved by memory devices (required but still reported
* as free from KVM / vhost).
*/
static unsigned int get_reserved_memslots(MachineState *ms)
{
if (ms->device_memory->used_memslots >
ms->device_memory->required_memslots) {
/* This is unexpected, and we warned already in the memory notifier. */
return 0;
}
return ms->device_memory->required_memslots -
ms->device_memory->used_memslots;
}
unsigned int memory_devices_get_reserved_memslots(void)
{
if (!current_machine->device_memory) {
return 0;
}
return get_reserved_memslots(current_machine);
}
bool memory_devices_memslot_auto_decision_active(void)
{
if (!current_machine->device_memory) {
return false;
}
return current_machine->device_memory->memslot_auto_decision_active;
}
static unsigned int memory_device_memslot_decision_limit(MachineState *ms,
MemoryRegion *mr)
{
const unsigned int reserved = get_reserved_memslots(ms);
const uint64_t size = memory_region_size(mr);
unsigned int max = vhost_get_max_memslots();
unsigned int free = vhost_get_free_memslots();
uint64_t available_space;
unsigned int memslots;
if (kvm_enabled()) {
max = MIN(max, kvm_get_max_memslots());
free = MIN(free, kvm_get_free_memslots());
}
/*
* If we only have less overall memslots than what we consider reasonable,
* just keep it to a minimum.
*/
if (max < MEMORY_DEVICES_SAFE_MAX_MEMSLOTS) {
return 1;
}
/*
* Consider our soft-limit across all memory devices. We don't really
* expect to exceed this limit in reasonable configurations.
*/
if (MEMORY_DEVICES_SOFT_MEMSLOT_LIMIT <=
ms->device_memory->required_memslots) {
return 1;
}
memslots = MEMORY_DEVICES_SOFT_MEMSLOT_LIMIT -
ms->device_memory->required_memslots;
/*
* Consider the actually still free memslots. This is only relevant if
* other memslot consumers would consume *significantly* more memslots than
* what we prepared for (> 253). Unlikely, but let's just handle it
* cleanly.
*/
memslots = MIN(memslots, free - reserved);
if (memslots < 1 || unlikely(free < reserved)) {
return 1;
}
/* We cannot have any other memory devices? So give all to this device. */
if (size == ms->maxram_size - ms->ram_size) {
return memslots;
}
/*
* Simple heuristic: equally distribute the memslots over the space
* still available for memory devices.
*/
available_space = ms->maxram_size - ms->ram_size -
ms->device_memory->used_region_size;
memslots = (double)memslots * size / available_space;
return memslots < 1 ? 1 : memslots;
}
static void memory_device_check_addable(MachineState *ms, MemoryDeviceState *md,
MemoryRegion *mr, Error **errp)
{
const MemoryDeviceClass *mdc = MEMORY_DEVICE_GET_CLASS(md);
const uint64_t used_region_size = ms->device_memory->used_region_size;
const uint64_t size = memory_region_size(mr);
const unsigned int reserved_memslots = get_reserved_memslots(ms);
unsigned int required_memslots, memslot_limit;
/*
* Instruct the device to decide how many memslots to use, if applicable,
* before we query the number of required memslots the first time.
*/
if (mdc->decide_memslots) {
memslot_limit = memory_device_memslot_decision_limit(ms, mr);
mdc->decide_memslots(md, memslot_limit);
}
required_memslots = memory_device_get_memslots(md);
/* we will need memory slots for kvm and vhost */
if (kvm_enabled() &&
kvm_get_free_memslots() < required_memslots + reserved_memslots) {
error_setg(errp, "hypervisor has not enough free memory slots left");
return;
}
if (vhost_get_free_memslots() < required_memslots + reserved_memslots) {
error_setg(errp, "a used vhost backend has not enough free memory slots left");
return;
}
/* will we exceed the total amount of memory specified */
if (used_region_size + size < used_region_size ||
used_region_size + size > ms->maxram_size - ms->ram_size) {
error_setg(errp, "not enough space, currently 0x%" PRIx64
" in use of total space for memory devices 0x" RAM_ADDR_FMT,
used_region_size, ms->maxram_size - ms->ram_size);
return;
}
}
static uint64_t memory_device_get_free_addr(MachineState *ms,
const uint64_t *hint,
uint64_t align, uint64_t size,
Error **errp)
{
GSList *list = NULL, *item;
Range as, new = range_empty;
range_init_nofail(&as, ms->device_memory->base,
memory_region_size(&ms->device_memory->mr));
/* start of address space indicates the maximum alignment we expect */
if (!QEMU_IS_ALIGNED(range_lob(&as), align)) {
warn_report("the alignment (0x%" PRIx64 ") exceeds the expected"
" maximum alignment, memory will get fragmented and not"
" all 'maxmem' might be usable for memory devices.",
align);
}
if (hint && !QEMU_IS_ALIGNED(*hint, align)) {
error_setg(errp, "address must be aligned to 0x%" PRIx64 " bytes",
align);
return 0;
}
if (hint) {
if (range_init(&new, *hint, size) || !range_contains_range(&as, &new)) {
error_setg(errp, "can't add memory device [0x%" PRIx64 ":0x%" PRIx64
"], usable range for memory devices [0x%" PRIx64 ":0x%"
PRIx64 "]", *hint, size, range_lob(&as),
range_size(&as));
return 0;
}
} else {
if (range_init(&new, QEMU_ALIGN_UP(range_lob(&as), align), size)) {
error_setg(errp, "can't add memory device, device too big");
return 0;
}
}
/* find address range that will fit new memory device */
object_child_foreach(OBJECT(ms), memory_device_build_list, &list);
for (item = list; item; item = g_slist_next(item)) {
const MemoryDeviceState *md = item->data;
const MemoryDeviceClass *mdc = MEMORY_DEVICE_GET_CLASS(OBJECT(md));
uint64_t next_addr;
Range tmp;
if (memory_device_is_empty(md)) {
continue;
}
range_init_nofail(&tmp, mdc->get_addr(md),
memory_device_get_region_size(md, &error_abort));
if (range_overlaps_range(&tmp, &new)) {
if (hint) {
const DeviceState *d = DEVICE(md);
error_setg(errp, "address range conflicts with memory device"
" id='%s'", d->id ? d->id : "(unnamed)");
goto out;
}
next_addr = QEMU_ALIGN_UP(range_upb(&tmp) + 1, align);
if (!next_addr || range_init(&new, next_addr, range_size(&new))) {
range_make_empty(&new);
break;
}
} else if (range_lob(&tmp) > range_upb(&new)) {
break;
}
}
if (!range_contains_range(&as, &new)) {
error_setg(errp, "could not find position in guest address space for "
"memory device - memory fragmented due to alignments");
}
out:
g_slist_free(list);
return range_lob(&new);
}
MemoryDeviceInfoList *qmp_memory_device_list(void)
{
GSList *devices = NULL, *item;
MemoryDeviceInfoList *list = NULL, **tail = &list;
object_child_foreach(qdev_get_machine(), memory_device_build_list,
&devices);
for (item = devices; item; item = g_slist_next(item)) {
const MemoryDeviceState *md = MEMORY_DEVICE(item->data);
const MemoryDeviceClass *mdc = MEMORY_DEVICE_GET_CLASS(item->data);
MemoryDeviceInfo *info = g_new0(MemoryDeviceInfo, 1);
/* Let's query infotmation even for empty memory devices. */
mdc->fill_device_info(md, info);
QAPI_LIST_APPEND(tail, info);
}
g_slist_free(devices);
return list;
}
static int memory_device_plugged_size(Object *obj, void *opaque)
{
uint64_t *size = opaque;
if (object_dynamic_cast(obj, TYPE_MEMORY_DEVICE)) {
const DeviceState *dev = DEVICE(obj);
const MemoryDeviceState *md = MEMORY_DEVICE(obj);
const MemoryDeviceClass *mdc = MEMORY_DEVICE_GET_CLASS(obj);
if (dev->realized && !memory_device_is_empty(md)) {
*size += mdc->get_plugged_size(md, &error_abort);
}
}
object_child_foreach(obj, memory_device_plugged_size, opaque);
return 0;
}
uint64_t get_plugged_memory_size(void)
{
uint64_t size = 0;
memory_device_plugged_size(qdev_get_machine(), &size);
return size;
}
void memory_device_pre_plug(MemoryDeviceState *md, MachineState *ms,
const uint64_t *legacy_align, Error **errp)
{
const MemoryDeviceClass *mdc = MEMORY_DEVICE_GET_CLASS(md);
Error *local_err = NULL;
uint64_t addr, align = 0;
MemoryRegion *mr;
/* We support empty memory devices even without device memory. */
if (memory_device_is_empty(md)) {
return;
}
if (!ms->device_memory) {
error_setg(errp, "the configuration is not prepared for memory devices"
" (e.g., for memory hotplug), consider specifying the"
" maxmem option");
return;
}
mr = mdc->get_memory_region(md, &local_err);
if (local_err) {
goto out;
}
memory_device_check_addable(ms, md, mr, &local_err);
if (local_err) {
goto out;
}
if (legacy_align) {
align = *legacy_align;
} else {
if (mdc->get_min_alignment) {
align = mdc->get_min_alignment(md);
}
align = MAX(align, memory_region_get_alignment(mr));
}
addr = mdc->get_addr(md);
addr = memory_device_get_free_addr(ms, !addr ? NULL : &addr, align,
memory_region_size(mr), &local_err);
if (local_err) {
goto out;
}
mdc->set_addr(md, addr, &local_err);
if (!local_err) {
trace_memory_device_pre_plug(DEVICE(md)->id ? DEVICE(md)->id : "",
addr);
}
out:
error_propagate(errp, local_err);
}
void memory_device_plug(MemoryDeviceState *md, MachineState *ms)
{
const MemoryDeviceClass *mdc = MEMORY_DEVICE_GET_CLASS(md);
unsigned int memslots;
uint64_t addr;
MemoryRegion *mr;
if (memory_device_is_empty(md)) {
return;
}
memslots = memory_device_get_memslots(md);
addr = mdc->get_addr(md);
/*
* We expect that a previous call to memory_device_pre_plug() succeeded, so
* it can't fail at this point.
*/
mr = mdc->get_memory_region(md, &error_abort);
g_assert(ms->device_memory);
ms->device_memory->used_region_size += memory_region_size(mr);
ms->device_memory->required_memslots += memslots;
if (mdc->decide_memslots && memslots > 1) {
ms->device_memory->memslot_auto_decision_active++;
}
memory_region_add_subregion(&ms->device_memory->mr,
addr - ms->device_memory->base, mr);
trace_memory_device_plug(DEVICE(md)->id ? DEVICE(md)->id : "", addr);
}
void memory_device_unplug(MemoryDeviceState *md, MachineState *ms)
{
const MemoryDeviceClass *mdc = MEMORY_DEVICE_GET_CLASS(md);
const unsigned int memslots = memory_device_get_memslots(md);
MemoryRegion *mr;
if (memory_device_is_empty(md)) {
return;
}
/*
* We expect that a previous call to memory_device_pre_plug() succeeded, so
* it can't fail at this point.
*/
mr = mdc->get_memory_region(md, &error_abort);
g_assert(ms->device_memory);
memory_region_del_subregion(&ms->device_memory->mr, mr);
if (mdc->decide_memslots && memslots > 1) {
ms->device_memory->memslot_auto_decision_active--;
}
ms->device_memory->used_region_size -= memory_region_size(mr);
ms->device_memory->required_memslots -= memslots;
trace_memory_device_unplug(DEVICE(md)->id ? DEVICE(md)->id : "",
mdc->get_addr(md));
}
uint64_t memory_device_get_region_size(const MemoryDeviceState *md,
Error **errp)
{
const MemoryDeviceClass *mdc = MEMORY_DEVICE_GET_CLASS(md);
MemoryRegion *mr;
/* dropping const here is fine as we don't touch the memory region */
mr = mdc->get_memory_region((MemoryDeviceState *)md, errp);
if (!mr) {
return 0;
}
return memory_region_size(mr);
}
static void memory_devices_region_mod(MemoryListener *listener,
MemoryRegionSection *mrs, bool add)
{
DeviceMemoryState *dms = container_of(listener, DeviceMemoryState,
listener);
if (!memory_region_is_ram(mrs->mr)) {
warn_report("Unexpected memory region mapped into device memory region.");
return;
}
/*
* The expectation is that each distinct RAM memory region section in
* our region for memory devices consumes exactly one memslot in KVM
* and in vhost. For vhost, this is true, except:
* * ROM memory regions don't consume a memslot. These get used very
* rarely for memory devices (R/O NVDIMMs).
* * Memslots without a fd (memory-backend-ram) don't necessarily
* consume a memslot. Such setups are quite rare and possibly bogus:
* the memory would be inaccessible by such vhost devices.
*
* So for vhost, in corner cases we might over-estimate the number of
* memslots that are currently used or that might still be reserved
* (required - used).
*/
dms->used_memslots += add ? 1 : -1;
if (dms->used_memslots > dms->required_memslots) {
warn_report("Memory devices use more memory slots than indicated as required.");
}
}
static void memory_devices_region_add(MemoryListener *listener,
MemoryRegionSection *mrs)
{
return memory_devices_region_mod(listener, mrs, true);
}
static void memory_devices_region_del(MemoryListener *listener,
MemoryRegionSection *mrs)
{
return memory_devices_region_mod(listener, mrs, false);
}
void machine_memory_devices_init(MachineState *ms, hwaddr base, uint64_t size)
{
g_assert(size);
g_assert(!ms->device_memory);
ms->device_memory = g_new0(DeviceMemoryState, 1);
ms->device_memory->base = base;
memory_region_init(&ms->device_memory->mr, OBJECT(ms), "device-memory",
size);
address_space_init(&ms->device_memory->as, &ms->device_memory->mr,
"device-memory");
memory_region_add_subregion(get_system_memory(), ms->device_memory->base,
&ms->device_memory->mr);
/* Track the number of memslots used by memory devices. */
ms->device_memory->listener.region_add = memory_devices_region_add;
ms->device_memory->listener.region_del = memory_devices_region_del;
memory_listener_register(&ms->device_memory->listener,
&ms->device_memory->as);
}
static const TypeInfo memory_device_info = {
.name = TYPE_MEMORY_DEVICE,
.parent = TYPE_INTERFACE,
.class_size = sizeof(MemoryDeviceClass),
};
static void memory_device_register_types(void)
{
type_register_static(&memory_device_info);
}
type_init(memory_device_register_types)