Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 82 insertions, 0 deletions

diff --git a/backends/hostmem-epc.c b/backends/hostmem-epc.c
new file mode 100644
index 000000000..b47f98b6a
--- /dev/null
+++ b/backends/hostmem-epc.c
@@ -0,0 +1,82 @@
+/*
+ * QEMU host SGX EPC memory backend
+ *
+ * Copyright (C) 2019 Intel Corporation
+ *
+ * Authors:
+ *   Sean Christopherson <sean.j.christopherson@intel.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 <sys/ioctl.h>
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "qom/object_interfaces.h"
+#include "qapi/error.h"
+#include "sysemu/hostmem.h"
+#include "hw/i386/hostmem-epc.h"
+
+static void
+sgx_epc_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
+{
+    uint32_t ram_flags;
+    char *name;
+    int fd;
+
+    if (!backend->size) {
+        error_setg(errp, "can't create backend with size 0");
+        return;
+    }
+
+    fd = qemu_open_old("/dev/sgx_vepc", O_RDWR);
+    if (fd < 0) {
+        error_setg_errno(errp, errno,
+                         "failed to open /dev/sgx_vepc to alloc SGX EPC");
+        return;
+    }
+
+    name = object_get_canonical_path(OBJECT(backend));
+    ram_flags = (backend->share ? RAM_SHARED : 0) | RAM_PROTECTED;
+    memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend),
+                                   name, backend->size, ram_flags,
+                                   fd, 0, errp);
+    g_free(name);
+}
+
+static void sgx_epc_backend_instance_init(Object *obj)
+{
+    HostMemoryBackend *m = MEMORY_BACKEND(obj);
+
+    m->share = true;
+    m->merge = false;
+    m->dump = false;
+}
+
+static void sgx_epc_backend_class_init(ObjectClass *oc, void *data)
+{
+    HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
+
+    bc->alloc = sgx_epc_backend_memory_alloc;
+}
+
+static const TypeInfo sgx_epc_backed_info = {
+    .name = TYPE_MEMORY_BACKEND_EPC,
+    .parent = TYPE_MEMORY_BACKEND,
+    .instance_init = sgx_epc_backend_instance_init,
+    .class_init = sgx_epc_backend_class_init,
+    .instance_size = sizeof(HostMemoryBackendEpc),
+};
+
+static void register_types(void)
+{
+    int fd = qemu_open_old("/dev/sgx_vepc", O_RDWR);
+    if (fd >= 0) {
+        close(fd);
+
+        type_register_static(&sgx_epc_backed_info);
+    }
+}
+
+type_init(register_types);