When option -mem-prealloc is used with one or more memory-backend objects, created backends may not obey configured bind policy or creation may fail after kernel attempts to move pages according to bind policy. Reason is in file_ram_alloc(), which will pre-allocate any descriptor based RAM if global mem_prealloc != 0 and that happens way before bind policy is applied to memory range. One way to fix it would be to extend memory_region_foo() API and add more invariants that could broken later due implicit dependencies that's hard to track. Another approach is to drop adhoc main RAM allocation and consolidate it around memory-backend. That allows to have single place that allocates guest RAM (main and memdev) in the same way and then global mem_prealloc could be replaced by backend's property[s] that will affect created memory-backend objects but only in correct order this time. With main RAM now converted to hostmem backends, there is no point in keeping global mem_prealloc around, so alias -mem-prealloc to "memory-backend.prealloc=on" machine compat[*] property and make mem_prealloc a local variable to only stir registration of compat property. *) currently user accessible -global works only with DEVICE based objects and extra work is needed to make it work with hostmem backends. But that is convenience option and out of scope of this already huge refactoring. Hence machine compat properties were used. Signed-off-by: Igor Mammedov <imammedo@redhat.com> Message-Id: <20200219160953.13771-78-imammedo@redhat.com>
533 lines
16 KiB
C
533 lines
16 KiB
C
/*
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* QEMU Host Memory Backend
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*
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* Copyright (C) 2013-2014 Red Hat Inc
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*
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* Authors:
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* Igor Mammedov <imammedo@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#include "qemu/osdep.h"
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#include "sysemu/hostmem.h"
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#include "sysemu/sysemu.h"
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#include "hw/boards.h"
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#include "qapi/error.h"
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#include "qapi/qapi-builtin-visit.h"
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#include "qapi/visitor.h"
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#include "qemu/config-file.h"
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#include "qom/object_interfaces.h"
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#include "qemu/mmap-alloc.h"
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#ifdef CONFIG_NUMA
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#include <numaif.h>
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QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_DEFAULT != MPOL_DEFAULT);
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QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_PREFERRED != MPOL_PREFERRED);
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QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_BIND != MPOL_BIND);
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QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_INTERLEAVE != MPOL_INTERLEAVE);
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#endif
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char *
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host_memory_backend_get_name(HostMemoryBackend *backend)
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{
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if (!backend->use_canonical_path) {
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return object_get_canonical_path_component(OBJECT(backend));
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}
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return object_get_canonical_path(OBJECT(backend));
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}
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static void
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host_memory_backend_get_size(Object *obj, Visitor *v, const char *name,
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void *opaque, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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uint64_t value = backend->size;
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visit_type_size(v, name, &value, errp);
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}
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static void
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host_memory_backend_set_size(Object *obj, Visitor *v, const char *name,
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void *opaque, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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Error *local_err = NULL;
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uint64_t value;
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if (host_memory_backend_mr_inited(backend)) {
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error_setg(&local_err, "cannot change property %s of %s ",
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name, object_get_typename(obj));
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goto out;
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}
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visit_type_size(v, name, &value, &local_err);
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if (local_err) {
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goto out;
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}
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if (!value) {
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error_setg(&local_err,
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"property '%s' of %s doesn't take value '%" PRIu64 "'",
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name, object_get_typename(obj), value);
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goto out;
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}
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backend->size = value;
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out:
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error_propagate(errp, local_err);
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}
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static void
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host_memory_backend_get_host_nodes(Object *obj, Visitor *v, const char *name,
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void *opaque, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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uint16List *host_nodes = NULL;
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uint16List **node = &host_nodes;
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unsigned long value;
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value = find_first_bit(backend->host_nodes, MAX_NODES);
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if (value == MAX_NODES) {
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goto ret;
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}
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*node = g_malloc0(sizeof(**node));
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(*node)->value = value;
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node = &(*node)->next;
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do {
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value = find_next_bit(backend->host_nodes, MAX_NODES, value + 1);
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if (value == MAX_NODES) {
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break;
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}
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*node = g_malloc0(sizeof(**node));
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(*node)->value = value;
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node = &(*node)->next;
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} while (true);
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ret:
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visit_type_uint16List(v, name, &host_nodes, errp);
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}
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static void
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host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
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void *opaque, Error **errp)
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{
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#ifdef CONFIG_NUMA
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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uint16List *l, *host_nodes = NULL;
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visit_type_uint16List(v, name, &host_nodes, errp);
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for (l = host_nodes; l; l = l->next) {
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if (l->value >= MAX_NODES) {
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error_setg(errp, "Invalid host-nodes value: %d", l->value);
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goto out;
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}
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}
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for (l = host_nodes; l; l = l->next) {
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bitmap_set(backend->host_nodes, l->value, 1);
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}
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out:
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qapi_free_uint16List(host_nodes);
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#else
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error_setg(errp, "NUMA node binding are not supported by this QEMU");
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#endif
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}
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static int
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host_memory_backend_get_policy(Object *obj, Error **errp G_GNUC_UNUSED)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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return backend->policy;
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}
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static void
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host_memory_backend_set_policy(Object *obj, int policy, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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backend->policy = policy;
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#ifndef CONFIG_NUMA
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if (policy != HOST_MEM_POLICY_DEFAULT) {
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error_setg(errp, "NUMA policies are not supported by this QEMU");
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}
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#endif
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}
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static bool host_memory_backend_get_merge(Object *obj, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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return backend->merge;
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}
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static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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if (!host_memory_backend_mr_inited(backend)) {
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backend->merge = value;
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return;
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}
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if (value != backend->merge) {
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void *ptr = memory_region_get_ram_ptr(&backend->mr);
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uint64_t sz = memory_region_size(&backend->mr);
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qemu_madvise(ptr, sz,
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value ? QEMU_MADV_MERGEABLE : QEMU_MADV_UNMERGEABLE);
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backend->merge = value;
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}
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}
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static bool host_memory_backend_get_dump(Object *obj, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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return backend->dump;
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}
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static void host_memory_backend_set_dump(Object *obj, bool value, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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if (!host_memory_backend_mr_inited(backend)) {
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backend->dump = value;
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return;
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}
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if (value != backend->dump) {
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void *ptr = memory_region_get_ram_ptr(&backend->mr);
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uint64_t sz = memory_region_size(&backend->mr);
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qemu_madvise(ptr, sz,
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value ? QEMU_MADV_DODUMP : QEMU_MADV_DONTDUMP);
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backend->dump = value;
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}
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}
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static bool host_memory_backend_get_prealloc(Object *obj, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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return backend->prealloc;
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}
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static void host_memory_backend_set_prealloc(Object *obj, bool value,
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Error **errp)
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{
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Error *local_err = NULL;
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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if (!host_memory_backend_mr_inited(backend)) {
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backend->prealloc = value;
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return;
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}
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if (value && !backend->prealloc) {
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int fd = memory_region_get_fd(&backend->mr);
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void *ptr = memory_region_get_ram_ptr(&backend->mr);
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uint64_t sz = memory_region_size(&backend->mr);
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os_mem_prealloc(fd, ptr, sz, backend->prealloc_threads, &local_err);
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if (local_err) {
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error_propagate(errp, local_err);
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return;
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}
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backend->prealloc = true;
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}
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}
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static void host_memory_backend_get_prealloc_threads(Object *obj, Visitor *v,
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const char *name, void *opaque, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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visit_type_uint32(v, name, &backend->prealloc_threads, errp);
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}
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static void host_memory_backend_set_prealloc_threads(Object *obj, Visitor *v,
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const char *name, void *opaque, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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Error *local_err = NULL;
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uint32_t value;
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visit_type_uint32(v, name, &value, &local_err);
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if (local_err) {
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goto out;
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}
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if (value <= 0) {
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error_setg(&local_err,
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"property '%s' of %s doesn't take value '%d'",
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name, object_get_typename(obj), value);
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goto out;
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}
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backend->prealloc_threads = value;
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out:
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error_propagate(errp, local_err);
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}
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static void host_memory_backend_init(Object *obj)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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MachineState *machine = MACHINE(qdev_get_machine());
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/* TODO: convert access to globals to compat properties */
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backend->merge = machine_mem_merge(machine);
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backend->dump = machine_dump_guest_core(machine);
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}
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static void host_memory_backend_post_init(Object *obj)
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{
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object_apply_compat_props(obj);
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}
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bool host_memory_backend_mr_inited(HostMemoryBackend *backend)
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{
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/*
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* NOTE: We forbid zero-length memory backend, so here zero means
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* "we haven't inited the backend memory region yet".
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*/
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return memory_region_size(&backend->mr) != 0;
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}
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MemoryRegion *host_memory_backend_get_memory(HostMemoryBackend *backend)
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{
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return host_memory_backend_mr_inited(backend) ? &backend->mr : NULL;
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}
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void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)
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{
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backend->is_mapped = mapped;
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}
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bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
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{
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return backend->is_mapped;
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}
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#ifdef __linux__
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size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
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{
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Object *obj = OBJECT(memdev);
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char *path = object_property_get_str(obj, "mem-path", NULL);
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size_t pagesize = qemu_mempath_getpagesize(path);
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g_free(path);
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return pagesize;
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}
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#else
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size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
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{
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return qemu_real_host_page_size;
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}
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#endif
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static void
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host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(uc);
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HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
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Error *local_err = NULL;
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void *ptr;
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uint64_t sz;
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if (bc->alloc) {
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bc->alloc(backend, &local_err);
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if (local_err) {
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goto out;
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}
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ptr = memory_region_get_ram_ptr(&backend->mr);
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sz = memory_region_size(&backend->mr);
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if (backend->merge) {
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qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
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}
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if (!backend->dump) {
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qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
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}
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#ifdef CONFIG_NUMA
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unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
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/* lastbit == MAX_NODES means maxnode = 0 */
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unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
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/* ensure policy won't be ignored in case memory is preallocated
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* before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
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* this doesn't catch hugepage case. */
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unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
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/* check for invalid host-nodes and policies and give more verbose
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* error messages than mbind(). */
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if (maxnode && backend->policy == MPOL_DEFAULT) {
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error_setg(errp, "host-nodes must be empty for policy default,"
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" or you should explicitly specify a policy other"
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" than default");
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return;
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} else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
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error_setg(errp, "host-nodes must be set for policy %s",
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HostMemPolicy_str(backend->policy));
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return;
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}
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/* We can have up to MAX_NODES nodes, but we need to pass maxnode+1
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* as argument to mbind() due to an old Linux bug (feature?) which
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* cuts off the last specified node. This means backend->host_nodes
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* must have MAX_NODES+1 bits available.
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*/
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assert(sizeof(backend->host_nodes) >=
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BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
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assert(maxnode <= MAX_NODES);
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if (mbind(ptr, sz, backend->policy,
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maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
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if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
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error_setg_errno(errp, errno,
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"cannot bind memory to host NUMA nodes");
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return;
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}
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}
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#endif
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/* Preallocate memory after the NUMA policy has been instantiated.
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* This is necessary to guarantee memory is allocated with
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* specified NUMA policy in place.
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*/
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if (backend->prealloc) {
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os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz,
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backend->prealloc_threads, &local_err);
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if (local_err) {
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goto out;
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}
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}
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}
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out:
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error_propagate(errp, local_err);
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}
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static bool
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host_memory_backend_can_be_deleted(UserCreatable *uc)
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{
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if (host_memory_backend_is_mapped(MEMORY_BACKEND(uc))) {
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return false;
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} else {
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return true;
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}
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}
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static bool host_memory_backend_get_share(Object *o, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(o);
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return backend->share;
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}
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static void host_memory_backend_set_share(Object *o, bool value, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(o);
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if (host_memory_backend_mr_inited(backend)) {
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error_setg(errp, "cannot change property value");
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return;
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}
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backend->share = value;
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}
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static bool
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host_memory_backend_get_use_canonical_path(Object *obj, Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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return backend->use_canonical_path;
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}
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static void
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host_memory_backend_set_use_canonical_path(Object *obj, bool value,
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Error **errp)
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{
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HostMemoryBackend *backend = MEMORY_BACKEND(obj);
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backend->use_canonical_path = value;
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}
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static void
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host_memory_backend_class_init(ObjectClass *oc, void *data)
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{
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UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
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ucc->complete = host_memory_backend_memory_complete;
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ucc->can_be_deleted = host_memory_backend_can_be_deleted;
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object_class_property_add_bool(oc, "merge",
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host_memory_backend_get_merge,
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host_memory_backend_set_merge, &error_abort);
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object_class_property_set_description(oc, "merge",
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"Mark memory as mergeable", &error_abort);
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object_class_property_add_bool(oc, "dump",
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host_memory_backend_get_dump,
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host_memory_backend_set_dump, &error_abort);
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object_class_property_set_description(oc, "dump",
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"Set to 'off' to exclude from core dump", &error_abort);
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object_class_property_add_bool(oc, "prealloc",
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host_memory_backend_get_prealloc,
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host_memory_backend_set_prealloc, &error_abort);
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object_class_property_set_description(oc, "prealloc",
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"Preallocate memory", &error_abort);
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object_class_property_add(oc, "prealloc-threads", "int",
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host_memory_backend_get_prealloc_threads,
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host_memory_backend_set_prealloc_threads,
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NULL, NULL, &error_abort);
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object_class_property_set_description(oc, "prealloc-threads",
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"Number of CPU threads to use for prealloc", &error_abort);
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object_class_property_add(oc, "size", "int",
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host_memory_backend_get_size,
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host_memory_backend_set_size,
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NULL, NULL, &error_abort);
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object_class_property_set_description(oc, "size",
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"Size of the memory region (ex: 500M)", &error_abort);
|
|
object_class_property_add(oc, "host-nodes", "int",
|
|
host_memory_backend_get_host_nodes,
|
|
host_memory_backend_set_host_nodes,
|
|
NULL, NULL, &error_abort);
|
|
object_class_property_set_description(oc, "host-nodes",
|
|
"Binds memory to the list of NUMA host nodes", &error_abort);
|
|
object_class_property_add_enum(oc, "policy", "HostMemPolicy",
|
|
&HostMemPolicy_lookup,
|
|
host_memory_backend_get_policy,
|
|
host_memory_backend_set_policy, &error_abort);
|
|
object_class_property_set_description(oc, "policy",
|
|
"Set the NUMA policy", &error_abort);
|
|
object_class_property_add_bool(oc, "share",
|
|
host_memory_backend_get_share, host_memory_backend_set_share,
|
|
&error_abort);
|
|
object_class_property_set_description(oc, "share",
|
|
"Mark the memory as private to QEMU or shared", &error_abort);
|
|
object_class_property_add_bool(oc, "x-use-canonical-path-for-ramblock-id",
|
|
host_memory_backend_get_use_canonical_path,
|
|
host_memory_backend_set_use_canonical_path, &error_abort);
|
|
}
|
|
|
|
static const TypeInfo host_memory_backend_info = {
|
|
.name = TYPE_MEMORY_BACKEND,
|
|
.parent = TYPE_OBJECT,
|
|
.abstract = true,
|
|
.class_size = sizeof(HostMemoryBackendClass),
|
|
.class_init = host_memory_backend_class_init,
|
|
.instance_size = sizeof(HostMemoryBackend),
|
|
.instance_init = host_memory_backend_init,
|
|
.instance_post_init = host_memory_backend_post_init,
|
|
.interfaces = (InterfaceInfo[]) {
|
|
{ TYPE_USER_CREATABLE },
|
|
{ }
|
|
}
|
|
};
|
|
|
|
static void register_types(void)
|
|
{
|
|
type_register_static(&host_memory_backend_info);
|
|
}
|
|
|
|
type_init(register_types);
|