backends/hostmem-file.c - third_party/qemu - Git at Google

 /*
  * 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 "qemu/osdep.h"
 #include "qapi/error.h"
 #include "qemu/error-report.h"
 #include "qemu/module.h"
 #include "qemu/madvise.h"
 #include "sysemu/hostmem.h"
 #include "qom/object_interfaces.h"
 #include "qom/object.h"
 #include "qapi/visitor.h"
 #include "qapi/qapi-visit-common.h"

 OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendFile, MEMORY_BACKEND_FILE)


 struct HostMemoryBackendFile {
     HostMemoryBackend parent_obj;

     char *mem_path;
     uint64_t align;
     uint64_t offset;
     bool discard_data;
     bool is_pmem;
     bool readonly;
     OnOffAuto rom;
 };

 static bool
 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
 {
 #ifndef CONFIG_POSIX
     error_setg(errp, "backend '%s' not supported on this host",
                object_get_typename(OBJECT(backend)));
     return false;
 #else
     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend);
     g_autofree gchar *name = NULL;
     uint32_t ram_flags;

     if (!backend->size) {
         error_setg(errp, "can't create backend with size 0");
         return false;
     }
     if (!fb->mem_path) {
         error_setg(errp, "mem-path property not set");
         return false;
     }

     switch (fb->rom) {
     case ON_OFF_AUTO_AUTO:
         /* Traditionally, opening the file readonly always resulted in ROM. */
         fb->rom = fb->readonly ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
         break;
     case ON_OFF_AUTO_ON:
         if (!fb->readonly) {
             error_setg(errp, "property 'rom' = 'on' is not supported with"
                        " 'readonly' = 'off'");
             return false;
         }
         break;
     case ON_OFF_AUTO_OFF:
         if (fb->readonly && backend->share) {
             error_setg(errp, "property 'rom' = 'off' is incompatible with"
                        " 'readonly' = 'on' and 'share' = 'on'");
             return false;
         }
         break;
     default:
         g_assert_not_reached();
     }

     name = host_memory_backend_get_name(backend);
     ram_flags = backend->share ? RAM_SHARED : 0;
     ram_flags |= fb->readonly ? RAM_READONLY_FD : 0;
     ram_flags |= fb->rom == ON_OFF_AUTO_ON ? RAM_READONLY : 0;
     ram_flags |= backend->reserve ? 0 : RAM_NORESERVE;
     ram_flags |= backend->guest_memfd ? RAM_GUEST_MEMFD : 0;
     ram_flags |= fb->is_pmem ? RAM_PMEM : 0;
     ram_flags |= RAM_NAMED_FILE;
     return memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), name,
                                             backend->size, fb->align, ram_flags,
                                             fb->mem_path, fb->offset, errp);
 #endif
 }

 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 (host_memory_backend_mr_inited(backend)) {
         error_setg(errp, "cannot change property 'mem-path' of %s",
                    object_get_typename(o));
         return;
     }
     g_free(fb->mem_path);
     fb->mem_path = g_strdup(str);
 }

 static bool file_memory_backend_get_discard_data(Object *o, Error **errp)
 {
     return MEMORY_BACKEND_FILE(o)->discard_data;
 }

 static void file_memory_backend_set_discard_data(Object *o, bool value,
                                                Error **errp)
 {
     MEMORY_BACKEND_FILE(o)->discard_data = value;
 }

 static void file_memory_backend_get_align(Object *o, Visitor *v,
                                           const char *name, void *opaque,
                                           Error **errp)
 {
     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
     uint64_t val = fb->align;

     visit_type_size(v, name, &val, errp);
 }

 static void file_memory_backend_set_align(Object *o, Visitor *v,
                                           const char *name, void *opaque,
                                           Error **errp)
 {
     HostMemoryBackend *backend = MEMORY_BACKEND(o);
     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
     uint64_t val;

     if (host_memory_backend_mr_inited(backend)) {
         error_setg(errp, "cannot change property '%s' of %s", name,
                    object_get_typename(o));
         return;
     }

     if (!visit_type_size(v, name, &val, errp)) {
         return;
     }
     fb->align = val;
 }

 static void file_memory_backend_get_offset(Object *o, Visitor *v,
                                           const char *name, void *opaque,
                                           Error **errp)
 {
     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
     uint64_t val = fb->offset;

     visit_type_size(v, name, &val, errp);
 }

 static void file_memory_backend_set_offset(Object *o, Visitor *v,
                                           const char *name, void *opaque,
                                           Error **errp)
 {
     HostMemoryBackend *backend = MEMORY_BACKEND(o);
     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
     uint64_t val;

     if (host_memory_backend_mr_inited(backend)) {
         error_setg(errp, "cannot change property '%s' of %s", name,
                    object_get_typename(o));
         return;
     }

     if (!visit_type_size(v, name, &val, errp)) {
         return;
     }
     fb->offset = val;
 }

 #ifdef CONFIG_LIBPMEM
 static bool file_memory_backend_get_pmem(Object *o, Error **errp)
 {
     return MEMORY_BACKEND_FILE(o)->is_pmem;
 }

 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp)
 {
     HostMemoryBackend *backend = MEMORY_BACKEND(o);
     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);

     if (host_memory_backend_mr_inited(backend)) {
         error_setg(errp, "cannot change property 'pmem' of %s.",
                    object_get_typename(o));
         return;
     }

     fb->is_pmem = value;
 }
 #endif /* CONFIG_LIBPMEM */

 static bool file_memory_backend_get_readonly(Object *obj, Error **errp)
 {
     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);

     return fb->readonly;
 }

 static void file_memory_backend_set_readonly(Object *obj, bool value,
                                              Error **errp)
 {
     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);

     if (host_memory_backend_mr_inited(backend)) {
         error_setg(errp, "cannot change property 'readonly' of %s.",
                    object_get_typename(obj));
         return;
     }

     fb->readonly = value;
 }

 static void file_memory_backend_get_rom(Object *obj, Visitor *v,
                                         const char *name, void *opaque,
                                         Error **errp)
 {
     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
     OnOffAuto rom = fb->rom;

     visit_type_OnOffAuto(v, name, &rom, errp);
 }

 static void file_memory_backend_set_rom(Object *obj, Visitor *v,
                                         const char *name, void *opaque,
                                         Error **errp)
 {
     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);

     if (host_memory_backend_mr_inited(backend)) {
         error_setg(errp, "cannot change property '%s' of %s.", name,
                    object_get_typename(obj));
         return;
     }

     visit_type_OnOffAuto(v, name, &fb->rom, errp);
 }

 static void file_backend_unparent(Object *obj)
 {
     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);

     if (host_memory_backend_mr_inited(backend) && fb->discard_data) {
         void *ptr = memory_region_get_ram_ptr(&backend->mr);
         uint64_t sz = memory_region_size(&backend->mr);

         qemu_madvise(ptr, sz, QEMU_MADV_REMOVE);
     }
 }

 static void
 file_backend_class_init(ObjectClass *oc, void *data)
 {
     HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);

     bc->alloc = file_backend_memory_alloc;
     oc->unparent = file_backend_unparent;

     object_class_property_add_bool(oc, "discard-data",
         file_memory_backend_get_discard_data, file_memory_backend_set_discard_data);
     object_class_property_add_str(oc, "mem-path",
         get_mem_path, set_mem_path);
     object_class_property_add(oc, "align", "int",
         file_memory_backend_get_align,
         file_memory_backend_set_align,
         NULL, NULL);
     object_class_property_add(oc, "offset", "int",
         file_memory_backend_get_offset,
         file_memory_backend_set_offset,
         NULL, NULL);
     object_class_property_set_description(oc, "offset",
         "Offset into the target file (ex: 1G)");
 #ifdef CONFIG_LIBPMEM
     object_class_property_add_bool(oc, "pmem",
         file_memory_backend_get_pmem, file_memory_backend_set_pmem);
 #endif
     object_class_property_add_bool(oc, "readonly",
         file_memory_backend_get_readonly,
         file_memory_backend_set_readonly);
     object_class_property_add(oc, "rom", "OnOffAuto",
         file_memory_backend_get_rom, file_memory_backend_set_rom, NULL, NULL);
     object_class_property_set_description(oc, "rom",
         "Whether to create Read Only Memory (ROM)");
 }

 static void file_backend_instance_finalize(Object *o)
 {
     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);

     g_free(fb->mem_path);
 }

 static const TypeInfo file_backend_info = {
     .name = TYPE_MEMORY_BACKEND_FILE,
     .parent = TYPE_MEMORY_BACKEND,
     .class_init = file_backend_class_init,
     .instance_finalize = file_backend_instance_finalize,
     .instance_size = sizeof(HostMemoryBackendFile),
 };

 static void register_types(void)
 {
     type_register_static(&file_backend_info);
 }

 type_init(register_types);
	/*
	* 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 "qemu/osdep.h"
	#include "qapi/error.h"
	#include "qemu/error-report.h"
	#include "qemu/module.h"
	#include "qemu/madvise.h"
	#include "sysemu/hostmem.h"
	#include "qom/object_interfaces.h"
	#include "qom/object.h"
	#include "qapi/visitor.h"
	#include "qapi/qapi-visit-common.h"

	OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendFile, MEMORY_BACKEND_FILE)


	struct HostMemoryBackendFile {
	HostMemoryBackend parent_obj;

	char *mem_path;
	uint64_t align;
	uint64_t offset;
	bool discard_data;
	bool is_pmem;
	bool readonly;
	OnOffAuto rom;
	};

	static bool
	file_backend_memory_alloc(HostMemoryBackend backend, Error *errp)
	{
	#ifndef CONFIG_POSIX
	error_setg(errp, "backend '%s' not supported on this host",
	object_get_typename(OBJECT(backend)));
	return false;
	#else
	HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend);
	g_autofree gchar *name = NULL;
	uint32_t ram_flags;

	if (!backend->size) {
	error_setg(errp, "can't create backend with size 0");
	return false;
	}
	if (!fb->mem_path) {
	error_setg(errp, "mem-path property not set");
	return false;
	}

	switch (fb->rom) {
	case ON_OFF_AUTO_AUTO:
	/* Traditionally, opening the file readonly always resulted in ROM. */
	fb->rom = fb->readonly ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
	break;
	case ON_OFF_AUTO_ON:
	if (!fb->readonly) {
	error_setg(errp, "property 'rom' = 'on' is not supported with"
	" 'readonly' = 'off'");
	return false;
	}
	break;
	case ON_OFF_AUTO_OFF:
	if (fb->readonly && backend->share) {
	error_setg(errp, "property 'rom' = 'off' is incompatible with"
	" 'readonly' = 'on' and 'share' = 'on'");
	return false;
	}
	break;
	default:
	g_assert_not_reached();
	}

	name = host_memory_backend_get_name(backend);
	ram_flags = backend->share ? RAM_SHARED : 0;
	ram_flags \|= fb->readonly ? RAM_READONLY_FD : 0;
	ram_flags \|= fb->rom == ON_OFF_AUTO_ON ? RAM_READONLY : 0;
	ram_flags \|= backend->reserve ? 0 : RAM_NORESERVE;
	ram_flags \|= backend->guest_memfd ? RAM_GUEST_MEMFD : 0;
	ram_flags \|= fb->is_pmem ? RAM_PMEM : 0;
	ram_flags \|= RAM_NAMED_FILE;
	return memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), name,
	backend->size, fb->align, ram_flags,
	fb->mem_path, fb->offset, errp);
	#endif
	}

	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 (host_memory_backend_mr_inited(backend)) {
	error_setg(errp, "cannot change property 'mem-path' of %s",
	object_get_typename(o));
	return;
	}
	g_free(fb->mem_path);
	fb->mem_path = g_strdup(str);
	}

	static bool file_memory_backend_get_discard_data(Object o, Error *errp)
	{
	return MEMORY_BACKEND_FILE(o)->discard_data;
	}

	static void file_memory_backend_set_discard_data(Object *o, bool value,
	Error **errp)
	{
	MEMORY_BACKEND_FILE(o)->discard_data = value;
	}

	static void file_memory_backend_get_align(Object o, Visitor v,
	const char name, void opaque,
	Error **errp)
	{
	HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
	uint64_t val = fb->align;

	visit_type_size(v, name, &val, errp);
	}

	static void file_memory_backend_set_align(Object o, Visitor v,
	const char name, void opaque,
	Error **errp)
	{
	HostMemoryBackend *backend = MEMORY_BACKEND(o);
	HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
	uint64_t val;

	if (host_memory_backend_mr_inited(backend)) {
	error_setg(errp, "cannot change property '%s' of %s", name,
	object_get_typename(o));
	return;
	}

	if (!visit_type_size(v, name, &val, errp)) {
	return;
	}
	fb->align = val;
	}

	static void file_memory_backend_get_offset(Object o, Visitor v,
	const char name, void opaque,
	Error **errp)
	{
	HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
	uint64_t val = fb->offset;

	visit_type_size(v, name, &val, errp);
	}

	static void file_memory_backend_set_offset(Object o, Visitor v,
	const char name, void opaque,
	Error **errp)
	{
	HostMemoryBackend *backend = MEMORY_BACKEND(o);
	HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
	uint64_t val;

	if (host_memory_backend_mr_inited(backend)) {
	error_setg(errp, "cannot change property '%s' of %s", name,
	object_get_typename(o));
	return;
	}

	if (!visit_type_size(v, name, &val, errp)) {
	return;
	}
	fb->offset = val;
	}

	#ifdef CONFIG_LIBPMEM
	static bool file_memory_backend_get_pmem(Object o, Error *errp)
	{
	return MEMORY_BACKEND_FILE(o)->is_pmem;
	}

	static void file_memory_backend_set_pmem(Object o, bool value, Error *errp)
	{
	HostMemoryBackend *backend = MEMORY_BACKEND(o);
	HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);

	if (host_memory_backend_mr_inited(backend)) {
	error_setg(errp, "cannot change property 'pmem' of %s.",
	object_get_typename(o));
	return;
	}

	fb->is_pmem = value;
	}
	#endif /* CONFIG_LIBPMEM */

	static bool file_memory_backend_get_readonly(Object obj, Error *errp)
	{
	HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);

	return fb->readonly;
	}

	static void file_memory_backend_set_readonly(Object *obj, bool value,
	Error **errp)
	{
	HostMemoryBackend *backend = MEMORY_BACKEND(obj);
	HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);

	if (host_memory_backend_mr_inited(backend)) {
	error_setg(errp, "cannot change property 'readonly' of %s.",
	object_get_typename(obj));
	return;
	}

	fb->readonly = value;
	}

	static void file_memory_backend_get_rom(Object obj, Visitor v,
	const char name, void opaque,
	Error **errp)
	{
	HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
	OnOffAuto rom = fb->rom;

	visit_type_OnOffAuto(v, name, &rom, errp);
	}

	static void file_memory_backend_set_rom(Object obj, Visitor v,
	const char name, void opaque,
	Error **errp)
	{
	HostMemoryBackend *backend = MEMORY_BACKEND(obj);
	HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);

	if (host_memory_backend_mr_inited(backend)) {
	error_setg(errp, "cannot change property '%s' of %s.", name,
	object_get_typename(obj));
	return;
	}

	visit_type_OnOffAuto(v, name, &fb->rom, errp);
	}

	static void file_backend_unparent(Object *obj)
	{
	HostMemoryBackend *backend = MEMORY_BACKEND(obj);
	HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);

	if (host_memory_backend_mr_inited(backend) && fb->discard_data) {
	void *ptr = memory_region_get_ram_ptr(&backend->mr);
	uint64_t sz = memory_region_size(&backend->mr);

	qemu_madvise(ptr, sz, QEMU_MADV_REMOVE);
	}
	}

	static void
	file_backend_class_init(ObjectClass oc, void data)
	{
	HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);

	bc->alloc = file_backend_memory_alloc;
	oc->unparent = file_backend_unparent;

	object_class_property_add_bool(oc, "discard-data",
	file_memory_backend_get_discard_data, file_memory_backend_set_discard_data);
	object_class_property_add_str(oc, "mem-path",
	get_mem_path, set_mem_path);
	object_class_property_add(oc, "align", "int",
	file_memory_backend_get_align,
	file_memory_backend_set_align,
	NULL, NULL);
	object_class_property_add(oc, "offset", "int",
	file_memory_backend_get_offset,
	file_memory_backend_set_offset,
	NULL, NULL);
	object_class_property_set_description(oc, "offset",
	"Offset into the target file (ex: 1G)");
	#ifdef CONFIG_LIBPMEM
	object_class_property_add_bool(oc, "pmem",
	file_memory_backend_get_pmem, file_memory_backend_set_pmem);
	#endif
	object_class_property_add_bool(oc, "readonly",
	file_memory_backend_get_readonly,
	file_memory_backend_set_readonly);
	object_class_property_add(oc, "rom", "OnOffAuto",
	file_memory_backend_get_rom, file_memory_backend_set_rom, NULL, NULL);
	object_class_property_set_description(oc, "rom",
	"Whether to create Read Only Memory (ROM)");
	}

	static void file_backend_instance_finalize(Object *o)
	{
	HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);

	g_free(fb->mem_path);
	}

	static const TypeInfo file_backend_info = {
	.name = TYPE_MEMORY_BACKEND_FILE,
	.parent = TYPE_MEMORY_BACKEND,
	.class_init = file_backend_class_init,
	.instance_finalize = file_backend_instance_finalize,
	.instance_size = sizeof(HostMemoryBackendFile),
	};

	static void register_types(void)
	{
	type_register_static(&file_backend_info);
	}

	type_init(register_types);