backends/hostmem-epc.c

   1 /*
   2  * QEMU host SGX EPC memory backend
   3  *
   4  * Copyright (C) 2019 Intel Corporation
   5  *
   6  * Authors:
   7  *   Sean Christopherson <sean.j.christopherson@intel.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include <sys/ioctl.h>
  15 #include "qom/object_interfaces.h"
  16 #include "qapi/error.h"
  17 #include "sysemu/hostmem.h"
  18 #include "hw/i386/hostmem-epc.h"
  19
  20 static void
  21 sgx_epc_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
  22 {
  23     uint32_t ram_flags;
  24     char *name;
  25     int fd;
  26
  27     if (!backend->size) {
  28         error_setg(errp, "can't create backend with size 0");
  29         return;
  30     }
  31
  32     fd = qemu_open_old("/dev/sgx_vepc", O_RDWR);
  33     if (fd < 0) {
  34         error_setg_errno(errp, errno,
  35                          "failed to open /dev/sgx_vepc to alloc SGX EPC");
  36         return;
  37     }
  38
  39     name = object_get_canonical_path(OBJECT(backend));
  40     ram_flags = (backend->share ? RAM_SHARED : 0) | RAM_PROTECTED;
  41     memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend),
  42                                    name, backend->size, ram_flags,
  43                                    fd, 0, errp);
  44     g_free(name);
  45 }
  46
  47 static void sgx_epc_backend_instance_init(Object *obj)
  48 {
  49     HostMemoryBackend *m = MEMORY_BACKEND(obj);
  50
  51     m->share = true;
  52     m->merge = false;
  53     m->dump = false;
  54 }
  55
  56 static void sgx_epc_backend_class_init(ObjectClass *oc, void *data)
  57 {
  58     HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
  59
  60     bc->alloc = sgx_epc_backend_memory_alloc;
  61 }
  62
  63 static const TypeInfo sgx_epc_backed_info = {
  64     .name = TYPE_MEMORY_BACKEND_EPC,
  65     .parent = TYPE_MEMORY_BACKEND,
  66     .instance_init = sgx_epc_backend_instance_init,
  67     .class_init = sgx_epc_backend_class_init,
  68     .instance_size = sizeof(HostMemoryBackendEpc),
  69 };
  70
  71 static void register_types(void)
  72 {
  73     int fd = qemu_open_old("/dev/sgx_vepc", O_RDWR);
  74     if (fd >= 0) {
  75         close(fd);
  76
  77         type_register_static(&sgx_epc_backed_info);
  78     }
  79 }
  80
  81 type_init(register_types);