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 #include <sys/ioctl.h>
  13
  14 #include "qemu/osdep.h"
  15 #include "qemu-common.h"
  16 #include "qom/object_interfaces.h"
  17 #include "qapi/error.h"
  18 #include "sysemu/hostmem.h"
  19 #include "hw/i386/hostmem-epc.h"
  20
  21 static void
  22 sgx_epc_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
  23 {
  24     uint32_t ram_flags;
  25     char *name;
  26     int fd;
  27
  28     if (!backend->size) {
  29         error_setg(errp, "can't create backend with size 0");
  30         return;
  31     }
  32
  33     fd = qemu_open_old("/dev/sgx_vepc", O_RDWR);
  34     if (fd < 0) {
  35         error_setg_errno(errp, errno,
  36                          "failed to open /dev/sgx_vepc to alloc SGX EPC");
  37         return;
  38     }
  39
  40     name = object_get_canonical_path(OBJECT(backend));
  41     ram_flags = (backend->share ? RAM_SHARED : 0) | RAM_PROTECTED;
  42     memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend),
  43                                    name, backend->size, ram_flags,
  44                                    fd, 0, errp);
  45     g_free(name);
  46 }
  47
  48 static void sgx_epc_backend_instance_init(Object *obj)
  49 {
  50     HostMemoryBackend *m = MEMORY_BACKEND(obj);
  51
  52     m->share = true;
  53     m->merge = false;
  54     m->dump = false;
  55 }
  56
  57 static void sgx_epc_backend_class_init(ObjectClass *oc, void *data)
  58 {
  59     HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
  60
  61     bc->alloc = sgx_epc_backend_memory_alloc;
  62 }
  63
  64 static const TypeInfo sgx_epc_backed_info = {
  65     .name = TYPE_MEMORY_BACKEND_EPC,
  66     .parent = TYPE_MEMORY_BACKEND,
  67     .instance_init = sgx_epc_backend_instance_init,
  68     .class_init = sgx_epc_backend_class_init,
  69     .instance_size = sizeof(HostMemoryBackendEpc),
  70 };
  71
  72 static void register_types(void)
  73 {
  74     int fd = qemu_open_old("/dev/sgx_vepc", O_RDWR);
  75     if (fd >= 0) {
  76         close(fd);
  77
  78         type_register_static(&sgx_epc_backed_info);
  79     }
  80 }
  81
  82 type_init(register_types);