hostmem: add file-based HostMemoryBackend

common-obj-$(CONFIG_TPM) += tpm.o

common-obj-y += hostmem.o hostmem-ram.o

common-obj-$(CONFIG_LINUX) += hostmem-file.o

/*

 * QEMU Host Memory Backend for hugetlbfs

 *

 * Copyright (C) 2013-2014 Red Hat Inc

 *

 * Authors:

 *   Paolo Bonzini <pbonzini@redhat.com>

 *

 * 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 "sysemu/hostmem.h"

#include "qom/object_interfaces.h"

/* hostmem-file.c */

/**

 * @TYPE_MEMORY_BACKEND_FILE:

 * name of backend that uses mmap on a file descriptor

 */

#define TYPE_MEMORY_BACKEND_FILE "memory-backend-file"

#define MEMORY_BACKEND_FILE(obj) \

    OBJECT_CHECK(HostMemoryBackendFile, (obj), TYPE_MEMORY_BACKEND_FILE)

typedef struct HostMemoryBackendFile HostMemoryBackendFile;

struct HostMemoryBackendFile {

    HostMemoryBackend parent_obj;

    char *mem_path;

};

static void

file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)

{

    HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend);

    if (!backend->size) {

        error_setg(errp, "can't create backend with size 0");

        return;

    }

    if (!fb->mem_path) {

        error_setg(errp, "mem_path property not set");

        return;

    }

#ifndef CONFIG_LINUX

    error_setg(errp, "-mem-path not supported on this host");

#else

    if (!memory_region_size(&backend->mr)) {

        memory_region_init_ram_from_file(&backend->mr, OBJECT(backend),

                                 object_get_canonical_path(OBJECT(backend)),

                                 backend->size,

                                 fb->mem_path, errp);

    }

#endif

}

static void

file_backend_class_init(ObjectClass *oc, void *data)

{

    HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);

    bc->alloc = file_backend_memory_alloc;

}

static char *get_mem_path(Object *o, Error **errp)

{

    HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);

    return g_strdup(fb->mem_path);

}

static void set_mem_path(Object *o, const char *str, Error **errp)

{

    HostMemoryBackend *backend = MEMORY_BACKEND(o);

    HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);

    if (memory_region_size(&backend->mr)) {

        error_setg(errp, "cannot change property value");

        return;

    }

    if (fb->mem_path) {

        g_free(fb->mem_path);

    }

    fb->mem_path = g_strdup(str);

}

static void

file_backend_instance_init(Object *o)

{

    object_property_add_str(o, "mem-path", get_mem_path,

                            set_mem_path, NULL);

}

static const TypeInfo file_backend_info = {

    .name = TYPE_MEMORY_BACKEND_FILE,

    .parent = TYPE_MEMORY_BACKEND,

    .class_init = file_backend_class_init,

    .instance_init = file_backend_instance_init,

    .instance_size = sizeof(HostMemoryBackendFile),

};

static void register_types(void)

{

    type_register_static(&file_backend_info);

}

type_init(register_types);