diff options
Diffstat (limited to 'backends/hostmem-memfd.c')
| -rw-r--r-- | backends/hostmem-memfd.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c new file mode 100644 index 000000000..3fc85c3db --- /dev/null +++ b/backends/hostmem-memfd.c @@ -0,0 +1,172 @@ +/* + * QEMU host memfd memory backend + * + * Copyright (C) 2018 Red Hat Inc + * + * Authors: + * Marc-André Lureau <marcandre.lureau@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 "sysemu/hostmem.h" +#include "qom/object_interfaces.h" +#include "qemu/memfd.h" +#include "qemu/module.h" +#include "qapi/error.h" +#include "qom/object.h" + +#define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd" + +OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendMemfd, MEMORY_BACKEND_MEMFD) + + +struct HostMemoryBackendMemfd { + HostMemoryBackend parent_obj; + + bool hugetlb; + uint64_t hugetlbsize; + bool seal; +}; + +static void +memfd_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) +{ + HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(backend); + uint32_t ram_flags; + char *name; + int fd; + + if (!backend->size) { + error_setg(errp, "can't create backend with size 0"); + return; + } + + fd = qemu_memfd_create(TYPE_MEMORY_BACKEND_MEMFD, backend->size, + m->hugetlb, m->hugetlbsize, m->seal ? + F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL : 0, + errp); + if (fd == -1) { + return; + } + + name = host_memory_backend_get_name(backend); + ram_flags = backend->share ? RAM_SHARED : 0; + ram_flags |= backend->reserve ? 0 : RAM_NORESERVE; + memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend), name, + backend->size, ram_flags, fd, 0, errp); + g_free(name); +} + +static bool +memfd_backend_get_hugetlb(Object *o, Error **errp) +{ + return MEMORY_BACKEND_MEMFD(o)->hugetlb; +} + +static void +memfd_backend_set_hugetlb(Object *o, bool value, Error **errp) +{ + MEMORY_BACKEND_MEMFD(o)->hugetlb = value; +} + +static void +memfd_backend_set_hugetlbsize(Object *obj, Visitor *v, const char *name, + void *opaque, Error **errp) +{ + HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj); + uint64_t value; + + if (host_memory_backend_mr_inited(MEMORY_BACKEND(obj))) { + error_setg(errp, "cannot change property value"); + return; + } + + if (!visit_type_size(v, name, &value, errp)) { + return; + } + if (!value) { + error_setg(errp, "Property '%s.%s' doesn't take value '%" PRIu64 "'", + object_get_typename(obj), name, value); + return; + } + m->hugetlbsize = value; +} + +static void +memfd_backend_get_hugetlbsize(Object *obj, Visitor *v, const char *name, + void *opaque, Error **errp) +{ + HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj); + uint64_t value = m->hugetlbsize; + + visit_type_size(v, name, &value, errp); +} + +static bool +memfd_backend_get_seal(Object *o, Error **errp) +{ + return MEMORY_BACKEND_MEMFD(o)->seal; +} + +static void +memfd_backend_set_seal(Object *o, bool value, Error **errp) +{ + MEMORY_BACKEND_MEMFD(o)->seal = value; +} + +static void +memfd_backend_instance_init(Object *obj) +{ + HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj); + + /* default to sealed file */ + m->seal = true; + MEMORY_BACKEND(m)->share = true; +} + +static void +memfd_backend_class_init(ObjectClass *oc, void *data) +{ + HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); + + bc->alloc = memfd_backend_memory_alloc; + + if (qemu_memfd_check(MFD_HUGETLB)) { + object_class_property_add_bool(oc, "hugetlb", + memfd_backend_get_hugetlb, + memfd_backend_set_hugetlb); + object_class_property_set_description(oc, "hugetlb", + "Use huge pages"); + object_class_property_add(oc, "hugetlbsize", "int", + memfd_backend_get_hugetlbsize, + memfd_backend_set_hugetlbsize, + NULL, NULL); + object_class_property_set_description(oc, "hugetlbsize", + "Huge pages size (ex: 2M, 1G)"); + } + object_class_property_add_bool(oc, "seal", + memfd_backend_get_seal, + memfd_backend_set_seal); + object_class_property_set_description(oc, "seal", + "Seal growing & shrinking"); +} + +static const TypeInfo memfd_backend_info = { + .name = TYPE_MEMORY_BACKEND_MEMFD, + .parent = TYPE_MEMORY_BACKEND, + .instance_init = memfd_backend_instance_init, + .class_init = memfd_backend_class_init, + .instance_size = sizeof(HostMemoryBackendMemfd), +}; + +static void register_types(void) +{ + if (qemu_memfd_check(MFD_ALLOW_SEALING)) { + type_register_static(&memfd_backend_info); + } +} + +type_init(register_types); |