@@ -9,6 +9,7 @@ common-obj-$(CONFIG_TPM) += tpm.o
common-obj-y += hostmem.o hostmem-ram.o
common-obj-$(CONFIG_LINUX) += hostmem-file.o
+common-obj-${CONFIG_XEN_BACKEND} += hostmem-xen.o
common-obj-y += cryptodev.o
common-obj-y += cryptodev-builtin.o
new file mode 100644
@@ -0,0 +1,121 @@
+/*
+ * QEMU Host Memory Backend for Xen
+ *
+ * Copyright(C) 2017 Intel Corporation.
+ *
+ * Author:
+ * Haozhong Zhang <haozhong.zhang@intel.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/mmap-alloc.h"
+#include "sysemu/hostmem.h"
+#include "qapi/error.h"
+#include "qom/object_interfaces.h"
+
+
+#define TYPE_MEMORY_BACKEND_XEN "memory-backend-xen"
+
+#define MEMORY_BACKEND_XEN(obj) \
+ OBJECT_CHECK(HostMemoryBackendXen, (obj), TYPE_MEMORY_BACKEND_XEN)
+
+typedef struct HostMemoryBackendXen HostMemoryBackendXen;
+
+struct HostMemoryBackendXen {
+ HostMemoryBackend parent_obj;
+
+ char *mem_path;
+};
+
+static void xen_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
+{
+ HostMemoryBackendXen *db = MEMORY_BACKEND_XEN(backend);
+ int fd;
+ size_t page_size;
+
+ if (!backend->size) {
+ error_setg(errp, "can't create backend with size 0");
+ return;
+ }
+ memory_region_init(&backend->mr,
+ OBJECT(backend), db->mem_path, backend->size);
+
+ fd = open(db->mem_path, O_RDONLY);
+ if (!fd) {
+ error_setg(errp, "can't open file %s, err %d", db->mem_path, errno);
+ return;
+ }
+ page_size = qemu_fd_getpagesize(fd);
+ backend->mr.align = MAX(page_size, QEMU_VMALLOC_ALIGN);
+ close(fd);
+}
+
+static void xen_backend_class_init(ObjectClass *oc, void *data)
+{
+ HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
+
+ bc->alloc = xen_backend_memory_alloc;
+}
+
+static char *get_mem_path(Object *o, Error **errp)
+{
+ HostMemoryBackendXen *db = MEMORY_BACKEND_XEN(o);
+
+ return g_strdup(db->mem_path);
+}
+
+static void set_mem_path(Object *o, const char *str, Error **errp)
+{
+ HostMemoryBackend *backend = MEMORY_BACKEND(o);
+ HostMemoryBackendXen *db = MEMORY_BACKEND_XEN(o);
+
+ if (memory_region_size(&backend->mr)) {
+ error_setg(errp, "cannot change property value");
+ return;
+ }
+ g_free(db->mem_path);
+ db->mem_path = g_strdup(str);
+}
+
+static void
+xen_backend_instance_init(Object *o)
+{
+ object_property_add_str(o, "mem-path", get_mem_path,
+ set_mem_path, NULL);
+}
+
+static void xen_backend_instance_finalize(Object *o)
+{
+ HostMemoryBackendXen *db = MEMORY_BACKEND_XEN(o);
+
+ g_free(db->mem_path);
+}
+
+static const TypeInfo xen_backend_info = {
+ .name = TYPE_MEMORY_BACKEND_XEN,
+ .parent = TYPE_MEMORY_BACKEND,
+ .class_init = xen_backend_class_init,
+ .instance_init = xen_backend_instance_init,
+ .instance_finalize = xen_backend_instance_finalize,
+ .instance_size = sizeof(HostMemoryBackendXen),
+};
+
+static void register_types(void)
+{
+ type_register_static(&xen_backend_info);
+}
+
+type_init(register_types);
@@ -18,6 +18,7 @@
#include "qapi-visit.h"
#include "qemu/config-file.h"
#include "qom/object_interfaces.h"
+#include "hw/xen/xen.h"
#ifdef CONFIG_NUMA
#include <numaif.h>
@@ -274,6 +275,13 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
goto out;
}
+ /* The backend storage of MEMORY_BACKEND_XEN is managed by Xen,
+ * so no further work in this function is needed.
+ */
+ if (xen_enabled() && !backend->mr.ram_block) {
+ goto out;
+ }
+
ptr = memory_region_get_ram_ptr(&backend->mr);
sz = memory_region_size(&backend->mr);
@@ -28,6 +28,7 @@
#include "sysemu/kvm.h"
#include "trace.h"
#include "hw/virtio/vhost.h"
+#include "hw/xen/xen.h"
typedef struct pc_dimms_capacity {
uint64_t size;
@@ -107,7 +108,9 @@ void pc_dimm_memory_plug(DeviceState *dev, MemoryHotplugState *hpms,
}
memory_region_add_subregion(&hpms->mr, addr - hpms->base, mr);
- vmstate_register_ram(vmstate_mr, dev);
+ if (!xen_enabled()) {
+ vmstate_register_ram(vmstate_mr, dev);
+ }
numa_set_mem_node_id(addr, memory_region_size(mr), dimm->node);
out:
Some virtual devices (e.g. NVDIMM) use the host memory backend to map its backend resources to the guest. When those devices are used on Xen, the mapping has to be managed out of QEMU. In order to reuse other parts of the implementation of those devices, we introduce a host memory backend for Xen (memory-backend-xen) which is mostly a placeholder that only creates an empty memory region and does not actually allocate and map the resource. Following is an example of a vNVDIMM device backed by a host pmem namespace, -object memory-backend-xen,id=mem1,mem-path=/dev/pmem0,size=4G -device nvdimm,id=nvdimm1,memdev=mem1 Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> --- Cc: Eduardo Habkost <ehabkost@redhat.com> Cc: Igor Mammedov <imammedo@redhat.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> --- backends/Makefile.objs | 1 + backends/hostmem-xen.c | 121 +++++++++++++++++++++++++++++++++++++++++++++++++ backends/hostmem.c | 8 ++++ hw/mem/pc-dimm.c | 5 +- 4 files changed, 134 insertions(+), 1 deletion(-) create mode 100644 backends/hostmem-xen.c