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-rw-r--r--backends/Makefile.objs2
-rw-r--r--backends/hostmem-memfd.c170
2 files changed, 172 insertions, 0 deletions
diff --git a/backends/Makefile.objs b/backends/Makefile.objs
index 0400799efd..67eeeba5fc 100644
--- a/backends/Makefile.objs
+++ b/backends/Makefile.objs
@@ -8,3 +8,5 @@ common-obj-$(CONFIG_LINUX) += hostmem-file.o
common-obj-y += cryptodev.o
common-obj-y += cryptodev-builtin.o
+
+common-obj-$(CONFIG_LINUX) += hostmem-memfd.o
diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c
new file mode 100644
index 0000000000..1e20fe0ba8
--- /dev/null
+++ b/backends/hostmem-memfd.c
@@ -0,0 +1,170 @@
+/*
+ * 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 "qemu-common.h"
+#include "sysemu/hostmem.h"
+#include "sysemu/sysemu.h"
+#include "qom/object_interfaces.h"
+#include "qemu/memfd.h"
+#include "qapi/error.h"
+
+#define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd"
+
+#define MEMORY_BACKEND_MEMFD(obj) \
+ OBJECT_CHECK(HostMemoryBackendMemfd, (obj), TYPE_MEMORY_BACKEND_MEMFD)
+
+typedef struct HostMemoryBackendMemfd HostMemoryBackendMemfd;
+
+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);
+ char *name;
+ int fd;
+
+ if (!backend->size) {
+ error_setg(errp, "can't create backend with size 0");
+ return;
+ }
+
+ if (host_memory_backend_mr_inited(backend)) {
+ return;
+ }
+
+ backend->force_prealloc = mem_prealloc;
+ 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 = object_get_canonical_path(OBJECT(backend));
+ memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend),
+ name, backend->size, true, fd, 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);
+ Error *local_err = NULL;
+ uint64_t value;
+
+ if (host_memory_backend_mr_inited(MEMORY_BACKEND(obj))) {
+ error_setg(&local_err, "cannot change property value");
+ goto out;
+ }
+
+ visit_type_size(v, name, &value, &local_err);
+ if (local_err) {
+ goto out;
+ }
+ if (!value) {
+ error_setg(&local_err, "Property '%s.%s' doesn't take value '%"
+ PRIu64 "'", object_get_typename(obj), name, value);
+ goto out;
+ }
+ m->hugetlbsize = value;
+out:
+ error_propagate(errp, local_err);
+}
+
+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;
+}
+
+static void
+memfd_backend_class_init(ObjectClass *oc, void *data)
+{
+ HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
+
+ bc->alloc = memfd_backend_memory_alloc;
+
+ object_class_property_add_bool(oc, "hugetlb",
+ memfd_backend_get_hugetlb,
+ memfd_backend_set_hugetlb,
+ &error_abort);
+ object_class_property_add(oc, "hugetlbsize", "int",
+ memfd_backend_get_hugetlbsize,
+ memfd_backend_set_hugetlbsize,
+ NULL, NULL, &error_abort);
+ object_class_property_add_bool(oc, "seal",
+ memfd_backend_get_seal,
+ memfd_backend_set_seal,
+ &error_abort);
+}
+
+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)
+{
+ type_register_static(&memfd_backend_info);
+}
+
+type_init(register_types);