qemu-e2k/numa.c

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/*
* NUMA parameter parsing routines
*
* Copyright (c) 2014 Fujitsu Ltd.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "sysemu/numa.h"
#include "exec/cpu-common.h"
#include "qemu/bitmap.h"
#include "qom/cpu.h"
#include "qemu/error-report.h"
#include "include/exec/cpu-common.h" /* for RAM_ADDR_FMT */
#include "qapi-visit.h"
#include "qapi/opts-visitor.h"
#include "hw/boards.h"
#include "sysemu/hostmem.h"
#include "qmp-commands.h"
#include "hw/mem/pc-dimm.h"
#include "qemu/option.h"
#include "qemu/config-file.h"
QemuOptsList qemu_numa_opts = {
.name = "numa",
.implied_opt_name = "type",
.head = QTAILQ_HEAD_INITIALIZER(qemu_numa_opts.head),
.desc = { { 0 } } /* validated with OptsVisitor */
};
static int have_memdevs = -1;
static int max_numa_nodeid; /* Highest specified NUMA node ID, plus one.
* For all nodes, nodeid < max_numa_nodeid
*/
int nb_numa_nodes;
NodeInfo numa_info[MAX_NODES];
void numa_set_mem_node_id(ram_addr_t addr, uint64_t size, uint32_t node)
{
struct numa_addr_range *range;
/*
* Memory-less nodes can come here with 0 size in which case,
* there is nothing to do.
*/
if (!size) {
return;
}
range = g_malloc0(sizeof(*range));
range->mem_start = addr;
range->mem_end = addr + size - 1;
QLIST_INSERT_HEAD(&numa_info[node].addr, range, entry);
}
void numa_unset_mem_node_id(ram_addr_t addr, uint64_t size, uint32_t node)
{
struct numa_addr_range *range, *next;
QLIST_FOREACH_SAFE(range, &numa_info[node].addr, entry, next) {
if (addr == range->mem_start && (addr + size - 1) == range->mem_end) {
QLIST_REMOVE(range, entry);
g_free(range);
return;
}
}
}
static void numa_set_mem_ranges(void)
{
int i;
ram_addr_t mem_start = 0;
/*
* Deduce start address of each node and use it to store
* the address range info in numa_info address range list
*/
for (i = 0; i < nb_numa_nodes; i++) {
numa_set_mem_node_id(mem_start, numa_info[i].node_mem, i);
mem_start += numa_info[i].node_mem;
}
}
/*
* Check if @addr falls under NUMA @node.
*/
static bool numa_addr_belongs_to_node(ram_addr_t addr, uint32_t node)
{
struct numa_addr_range *range;
QLIST_FOREACH(range, &numa_info[node].addr, entry) {
if (addr >= range->mem_start && addr <= range->mem_end) {
return true;
}
}
return false;
}
/*
* Given an address, return the index of the NUMA node to which the
* address belongs to.
*/
uint32_t numa_get_node(ram_addr_t addr, Error **errp)
{
uint32_t i;
/* For non NUMA configurations, check if the addr falls under node 0 */
if (!nb_numa_nodes) {
if (numa_addr_belongs_to_node(addr, 0)) {
return 0;
}
}
for (i = 0; i < nb_numa_nodes; i++) {
if (numa_addr_belongs_to_node(addr, i)) {
return i;
}
}
error_setg(errp, "Address 0x" RAM_ADDR_FMT " doesn't belong to any "
"NUMA node", addr);
return -1;
}
static void numa_node_parse(NumaNodeOptions *node, QemuOpts *opts, Error **errp)
{
uint16_t nodenr;
uint16List *cpus = NULL;
if (node->has_nodeid) {
nodenr = node->nodeid;
} else {
nodenr = nb_numa_nodes;
}
if (nodenr >= MAX_NODES) {
error_setg(errp, "Max number of NUMA nodes reached: %"
PRIu16 "", nodenr);
return;
}
if (numa_info[nodenr].present) {
error_setg(errp, "Duplicate NUMA nodeid: %" PRIu16, nodenr);
return;
}
for (cpus = node->cpus; cpus; cpus = cpus->next) {
if (cpus->value >= max_cpus) {
error_setg(errp,
"CPU index (%" PRIu16 ")"
" should be smaller than maxcpus (%d)",
cpus->value, max_cpus);
return;
}
bitmap_set(numa_info[nodenr].node_cpu, cpus->value, 1);
}
if (node->has_mem && node->has_memdev) {
error_setg(errp, "qemu: cannot specify both mem= and memdev=");
return;
}
if (have_memdevs == -1) {
have_memdevs = node->has_memdev;
}
if (node->has_memdev != have_memdevs) {
error_setg(errp, "qemu: memdev option must be specified for either "
"all or no nodes");
return;
}
if (node->has_mem) {
uint64_t mem_size = node->mem;
const char *mem_str = qemu_opt_get(opts, "mem");
/* Fix up legacy suffix-less format */
if (g_ascii_isdigit(mem_str[strlen(mem_str) - 1])) {
mem_size <<= 20;
}
numa_info[nodenr].node_mem = mem_size;
}
if (node->has_memdev) {
Object *o;
o = object_resolve_path_type(node->memdev, TYPE_MEMORY_BACKEND, NULL);
if (!o) {
error_setg(errp, "memdev=%s is ambiguous", node->memdev);
return;
}
object_ref(o);
numa_info[nodenr].node_mem = object_property_get_int(o, "size", NULL);
numa_info[nodenr].node_memdev = MEMORY_BACKEND(o);
}
numa_info[nodenr].present = true;
max_numa_nodeid = MAX(max_numa_nodeid, nodenr + 1);
}
static int parse_numa(void *opaque, QemuOpts *opts, Error **errp)
{
NumaOptions *object = NULL;
Error *err = NULL;
{
OptsVisitor *ov = opts_visitor_new(opts);
qapi: Swap visit_* arguments for consistent 'name' placement JSON uses "name":value, but many of our visitor interfaces were called with visit_type_FOO(v, &value, name, errp). This can be a bit confusing to have to mentally swap the parameter order to match JSON order. It's particularly bad for visit_start_struct(), where the 'name' parameter is smack in the middle of the otherwise-related group of 'obj, kind, size' parameters! It's time to do a global swap of the parameter ordering, so that the 'name' parameter is always immediately after the Visitor argument. Additional reason in favor of the swap: the existing include/qjson.h prefers listing 'name' first in json_prop_*(), and I have plans to unify that file with the qapi visitors; listing 'name' first in qapi will minimize churn to the (admittedly few) qjson.h clients. Later patches will then fix docs, object.h, visitor-impl.h, and those clients to match. Done by first patching scripts/qapi*.py by hand to make generated files do what I want, then by running the following Coccinelle script to affect the rest of the code base: $ spatch --sp-file script `git grep -l '\bvisit_' -- '**/*.[ch]'` I then had to apply some touchups (Coccinelle insisted on TAB indentation in visitor.h, and botched the signature of visit_type_enum() by rewriting 'const char *const strings[]' to the syntactically invalid 'const char*const[] strings'). The movement of parameters is sufficient to provoke compiler errors if any callers were missed. // Part 1: Swap declaration order @@ type TV, TErr, TObj, T1, T2; identifier OBJ, ARG1, ARG2; @@ void visit_start_struct -(TV v, TObj OBJ, T1 ARG1, const char *name, T2 ARG2, TErr errp) +(TV v, const char *name, TObj OBJ, T1 ARG1, T2 ARG2, TErr errp) { ... } @@ type bool, TV, T1; identifier ARG1; @@ bool visit_optional -(TV v, T1 ARG1, const char *name) +(TV v, const char *name, T1 ARG1) { ... } @@ type TV, TErr, TObj, T1; identifier OBJ, ARG1; @@ void visit_get_next_type -(TV v, TObj OBJ, T1 ARG1, const char *name, TErr errp) +(TV v, const char *name, TObj OBJ, T1 ARG1, TErr errp) { ... } @@ type TV, TErr, TObj, T1, T2; identifier OBJ, ARG1, ARG2; @@ void visit_type_enum -(TV v, TObj OBJ, T1 ARG1, T2 ARG2, const char *name, TErr errp) +(TV v, const char *name, TObj OBJ, T1 ARG1, T2 ARG2, TErr errp) { ... } @@ type TV, TErr, TObj; identifier OBJ; identifier VISIT_TYPE =~ "^visit_type_"; @@ void VISIT_TYPE -(TV v, TObj OBJ, const char *name, TErr errp) +(TV v, const char *name, TObj OBJ, TErr errp) { ... } // Part 2: swap caller order @@ expression V, NAME, OBJ, ARG1, ARG2, ERR; identifier VISIT_TYPE =~ "^visit_type_"; @@ ( -visit_start_struct(V, OBJ, ARG1, NAME, ARG2, ERR) +visit_start_struct(V, NAME, OBJ, ARG1, ARG2, ERR) | -visit_optional(V, ARG1, NAME) +visit_optional(V, NAME, ARG1) | -visit_get_next_type(V, OBJ, ARG1, NAME, ERR) +visit_get_next_type(V, NAME, OBJ, ARG1, ERR) | -visit_type_enum(V, OBJ, ARG1, ARG2, NAME, ERR) +visit_type_enum(V, NAME, OBJ, ARG1, ARG2, ERR) | -VISIT_TYPE(V, OBJ, NAME, ERR) +VISIT_TYPE(V, NAME, OBJ, ERR) ) Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <1454075341-13658-19-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-01-29 14:48:54 +01:00
visit_type_NumaOptions(opts_get_visitor(ov), NULL, &object, &err);
opts_visitor_cleanup(ov);
}
if (err) {
goto error;
}
switch (object->type) {
case NUMA_OPTIONS_KIND_NODE:
numa_node_parse(object->u.node, opts, &err);
if (err) {
goto error;
}
nb_numa_nodes++;
break;
default:
abort();
}
return 0;
error:
error_report_err(err);
qapi_free_NumaOptions(object);
return -1;
}
static char *enumerate_cpus(unsigned long *cpus, int max_cpus)
{
int cpu;
bool first = true;
GString *s = g_string_new(NULL);
for (cpu = find_first_bit(cpus, max_cpus);
cpu < max_cpus;
cpu = find_next_bit(cpus, max_cpus, cpu + 1)) {
g_string_append_printf(s, "%s%d", first ? "" : " ", cpu);
first = false;
}
return g_string_free(s, FALSE);
}
static void validate_numa_cpus(void)
{
int i;
DECLARE_BITMAP(seen_cpus, MAX_CPUMASK_BITS);
bitmap_zero(seen_cpus, MAX_CPUMASK_BITS);
for (i = 0; i < nb_numa_nodes; i++) {
if (bitmap_intersects(seen_cpus, numa_info[i].node_cpu,
MAX_CPUMASK_BITS)) {
bitmap_and(seen_cpus, seen_cpus,
numa_info[i].node_cpu, MAX_CPUMASK_BITS);
error_report("CPU(s) present in multiple NUMA nodes: %s",
enumerate_cpus(seen_cpus, max_cpus));
exit(EXIT_FAILURE);
}
bitmap_or(seen_cpus, seen_cpus,
numa_info[i].node_cpu, MAX_CPUMASK_BITS);
}
2015-02-09 20:35:04 +01:00
if (!bitmap_full(seen_cpus, max_cpus)) {
char *msg;
bitmap_complement(seen_cpus, seen_cpus, max_cpus);
msg = enumerate_cpus(seen_cpus, max_cpus);
error_report("warning: CPU(s) not present in any NUMA nodes: %s", msg);
error_report("warning: All CPU(s) up to maxcpus should be described "
"in NUMA config");
g_free(msg);
}
}
void parse_numa_opts(MachineClass *mc)
{
int i;
if (qemu_opts_foreach(qemu_find_opts("numa"), parse_numa, NULL, NULL)) {
exit(1);
}
assert(max_numa_nodeid <= MAX_NODES);
/* No support for sparse NUMA node IDs yet: */
for (i = max_numa_nodeid - 1; i >= 0; i--) {
/* Report large node IDs first, to make mistakes easier to spot */
if (!numa_info[i].present) {
error_report("numa: Node ID missing: %d", i);
exit(1);
}
}
/* This must be always true if all nodes are present: */
assert(nb_numa_nodes == max_numa_nodeid);
if (nb_numa_nodes > 0) {
uint64_t numa_total;
if (nb_numa_nodes > MAX_NODES) {
nb_numa_nodes = MAX_NODES;
}
/* If no memory size is given for any node, assume the default case
* and distribute the available memory equally across all nodes
*/
for (i = 0; i < nb_numa_nodes; i++) {
if (numa_info[i].node_mem != 0) {
break;
}
}
if (i == nb_numa_nodes) {
uint64_t usedmem = 0;
/* On Linux, each node's border has to be 8MB aligned,
* the final node gets the rest.
*/
for (i = 0; i < nb_numa_nodes - 1; i++) {
numa_info[i].node_mem = (ram_size / nb_numa_nodes) &
~((1 << 23UL) - 1);
usedmem += numa_info[i].node_mem;
}
numa_info[i].node_mem = ram_size - usedmem;
}
numa_total = 0;
for (i = 0; i < nb_numa_nodes; i++) {
numa_total += numa_info[i].node_mem;
}
if (numa_total != ram_size) {
error_report("total memory for NUMA nodes (0x%" PRIx64 ")"
" should equal RAM size (0x" RAM_ADDR_FMT ")",
numa_total, ram_size);
exit(1);
}
for (i = 0; i < nb_numa_nodes; i++) {
QLIST_INIT(&numa_info[i].addr);
}
numa_set_mem_ranges();
for (i = 0; i < nb_numa_nodes; i++) {
if (!bitmap_empty(numa_info[i].node_cpu, MAX_CPUMASK_BITS)) {
break;
}
}
/* Historically VCPUs were assigned in round-robin order to NUMA
* nodes. However it causes issues with guest not handling it nice
* in case where cores/threads from a multicore CPU appear on
* different nodes. So allow boards to override default distribution
* rule grouping VCPUs by socket so that VCPUs from the same socket
* would be on the same node.
*/
if (i == nb_numa_nodes) {
for (i = 0; i < max_cpus; i++) {
unsigned node_id = i % nb_numa_nodes;
if (mc->cpu_index_to_socket_id) {
node_id = mc->cpu_index_to_socket_id(i) % nb_numa_nodes;
}
set_bit(i, numa_info[node_id].node_cpu);
}
}
validate_numa_cpus();
} else {
numa_set_mem_node_id(0, ram_size, 0);
}
}
void numa_post_machine_init(void)
{
CPUState *cpu;
int i;
CPU_FOREACH(cpu) {
for (i = 0; i < nb_numa_nodes; i++) {
if (test_bit(cpu->cpu_index, numa_info[i].node_cpu)) {
cpu->numa_node = i;
}
}
}
}
static void allocate_system_memory_nonnuma(MemoryRegion *mr, Object *owner,
const char *name,
uint64_t ram_size)
{
if (mem_path) {
#ifdef __linux__
Error *err = NULL;
memory_region_init_ram_from_file(mr, owner, name, ram_size, false,
mem_path, &err);
if (err) {
error_report_err(err);
if (mem_prealloc) {
exit(1);
}
/* Legacy behavior: if allocation failed, fall back to
* regular RAM allocation.
*/
Fix bad error handling after memory_region_init_ram() Symptom: $ qemu-system-x86_64 -m 10000000 Unexpected error in ram_block_add() at /work/armbru/qemu/exec.c:1456: upstream-qemu: cannot set up guest memory 'pc.ram': Cannot allocate memory Aborted (core dumped) Root cause: commit ef701d7 screwed up handling of out-of-memory conditions. Before the commit, we report the error and exit(1), in one place, ram_block_add(). The commit lifts the error handling up the call chain some, to three places. Fine. Except it uses &error_abort in these places, changing the behavior from exit(1) to abort(), and thus undoing the work of commit 3922825 "exec: Don't abort when we can't allocate guest memory". The three places are: * memory_region_init_ram() Commit 4994653 (right after commit ef701d7) lifted the error handling further, through memory_region_init_ram(), multiplying the incorrect use of &error_abort. Later on, imitation of existing (bad) code may have created more. * memory_region_init_ram_ptr() The &error_abort is still there. * memory_region_init_rom_device() Doesn't need fixing, because commit 33e0eb5 (soon after commit ef701d7) lifted the error handling further, and in the process changed it from &error_abort to passing it up the call chain. Correct, because the callers are realize() methods. Fix the error handling after memory_region_init_ram() with a Coccinelle semantic patch: @r@ expression mr, owner, name, size, err; position p; @@ memory_region_init_ram(mr, owner, name, size, ( - &error_abort + &error_fatal | err@p ) ); @script:python@ p << r.p; @@ print "%s:%s:%s" % (p[0].file, p[0].line, p[0].column) When the last argument is &error_abort, it gets replaced by &error_fatal. This is the fix. If the last argument is anything else, its position is reported. This lets us check the fix is complete. Four positions get reported: * ram_backend_memory_alloc() Error is passed up the call chain, ultimately through user_creatable_complete(). As far as I can tell, it's callers all handle the error sanely. * fsl_imx25_realize(), fsl_imx31_realize(), dp8393x_realize() DeviceClass.realize() methods, errors handled sanely further up the call chain. We're good. Test case again behaves: $ qemu-system-x86_64 -m 10000000 qemu-system-x86_64: cannot set up guest memory 'pc.ram': Cannot allocate memory [Exit 1 ] The next commits will repair the rest of commit ef701d7's damage. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1441983105-26376-3-git-send-email-armbru@redhat.com> Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
2015-09-11 16:51:43 +02:00
memory_region_init_ram(mr, owner, name, ram_size, &error_fatal);
}
#else
fprintf(stderr, "-mem-path not supported on this host\n");
exit(1);
#endif
} else {
Fix bad error handling after memory_region_init_ram() Symptom: $ qemu-system-x86_64 -m 10000000 Unexpected error in ram_block_add() at /work/armbru/qemu/exec.c:1456: upstream-qemu: cannot set up guest memory 'pc.ram': Cannot allocate memory Aborted (core dumped) Root cause: commit ef701d7 screwed up handling of out-of-memory conditions. Before the commit, we report the error and exit(1), in one place, ram_block_add(). The commit lifts the error handling up the call chain some, to three places. Fine. Except it uses &error_abort in these places, changing the behavior from exit(1) to abort(), and thus undoing the work of commit 3922825 "exec: Don't abort when we can't allocate guest memory". The three places are: * memory_region_init_ram() Commit 4994653 (right after commit ef701d7) lifted the error handling further, through memory_region_init_ram(), multiplying the incorrect use of &error_abort. Later on, imitation of existing (bad) code may have created more. * memory_region_init_ram_ptr() The &error_abort is still there. * memory_region_init_rom_device() Doesn't need fixing, because commit 33e0eb5 (soon after commit ef701d7) lifted the error handling further, and in the process changed it from &error_abort to passing it up the call chain. Correct, because the callers are realize() methods. Fix the error handling after memory_region_init_ram() with a Coccinelle semantic patch: @r@ expression mr, owner, name, size, err; position p; @@ memory_region_init_ram(mr, owner, name, size, ( - &error_abort + &error_fatal | err@p ) ); @script:python@ p << r.p; @@ print "%s:%s:%s" % (p[0].file, p[0].line, p[0].column) When the last argument is &error_abort, it gets replaced by &error_fatal. This is the fix. If the last argument is anything else, its position is reported. This lets us check the fix is complete. Four positions get reported: * ram_backend_memory_alloc() Error is passed up the call chain, ultimately through user_creatable_complete(). As far as I can tell, it's callers all handle the error sanely. * fsl_imx25_realize(), fsl_imx31_realize(), dp8393x_realize() DeviceClass.realize() methods, errors handled sanely further up the call chain. We're good. Test case again behaves: $ qemu-system-x86_64 -m 10000000 qemu-system-x86_64: cannot set up guest memory 'pc.ram': Cannot allocate memory [Exit 1 ] The next commits will repair the rest of commit ef701d7's damage. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1441983105-26376-3-git-send-email-armbru@redhat.com> Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
2015-09-11 16:51:43 +02:00
memory_region_init_ram(mr, owner, name, ram_size, &error_fatal);
}
vmstate_register_ram_global(mr);
}
void memory_region_allocate_system_memory(MemoryRegion *mr, Object *owner,
const char *name,
uint64_t ram_size)
{
uint64_t addr = 0;
int i;
if (nb_numa_nodes == 0 || !have_memdevs) {
allocate_system_memory_nonnuma(mr, owner, name, ram_size);
return;
}
memory_region_init(mr, owner, name, ram_size);
for (i = 0; i < MAX_NODES; i++) {
uint64_t size = numa_info[i].node_mem;
HostMemoryBackend *backend = numa_info[i].node_memdev;
if (!backend) {
continue;
}
MemoryRegion *seg = host_memory_backend_get_memory(backend,
&error_fatal);
if (memory_region_is_mapped(seg)) {
char *path = object_get_canonical_path_component(OBJECT(backend));
error_report("memory backend %s is used multiple times. Each "
"-numa option must use a different memdev value.",
path);
exit(1);
}
memory_region_add_subregion(mr, addr, seg);
vmstate_register_ram_global(seg);
addr += size;
}
}
static void numa_stat_memory_devices(uint64_t node_mem[])
{
MemoryDeviceInfoList *info_list = NULL;
MemoryDeviceInfoList **prev = &info_list;
MemoryDeviceInfoList *info;
qmp_pc_dimm_device_list(qdev_get_machine(), &prev);
for (info = info_list; info; info = info->next) {
MemoryDeviceInfo *value = info->value;
if (value) {
switch (value->type) {
case MEMORY_DEVICE_INFO_KIND_DIMM:
node_mem[value->u.dimm->node] += value->u.dimm->size;
break;
default:
break;
}
}
}
qapi_free_MemoryDeviceInfoList(info_list);
}
void query_numa_node_mem(uint64_t node_mem[])
{
int i;
if (nb_numa_nodes <= 0) {
return;
}
numa_stat_memory_devices(node_mem);
for (i = 0; i < nb_numa_nodes; i++) {
node_mem[i] += numa_info[i].node_mem;
}
}
static int query_memdev(Object *obj, void *opaque)
{
MemdevList **list = opaque;
MemdevList *m = NULL;
if (object_dynamic_cast(obj, TYPE_MEMORY_BACKEND)) {
m = g_malloc0(sizeof(*m));
m->value = g_malloc0(sizeof(*m->value));
m->value->size = object_property_get_int(obj, "size",
&error_abort);
m->value->merge = object_property_get_bool(obj, "merge",
&error_abort);
m->value->dump = object_property_get_bool(obj, "dump",
&error_abort);
m->value->prealloc = object_property_get_bool(obj,
"prealloc",
&error_abort);
m->value->policy = object_property_get_enum(obj,
"policy",
"HostMemPolicy",
&error_abort);
object_property_get_uint16List(obj, "host-nodes",
&m->value->host_nodes,
&error_abort);
m->next = *list;
*list = m;
}
return 0;
}
MemdevList *qmp_query_memdev(Error **errp)
{
Object *obj = object_get_objects_root();
MemdevList *list = NULL;
object_child_foreach(obj, query_memdev, &list);
return list;
}