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 bool
  21 sgx_epc_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
  22 {
  23     g_autofree char *name = NULL;
  24     uint32_t ram_flags;
  25     int fd;
  26
  27     if (!backend->size) {
  28         error_setg(errp, "can't create backend with size 0");
  29         return false;
  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 false;
  37     }
  38
  39     backend->aligned = true;
  40     name = object_get_canonical_path(OBJECT(backend));
  41     ram_flags = (backend->share ? RAM_SHARED : 0) | RAM_PROTECTED;
  42     return memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend), name,
  43                                           backend->size, ram_flags, fd, 0, errp);
  44 }
  45
  46 static void sgx_epc_backend_instance_init(Object *obj)
  47 {
  48     HostMemoryBackend *m = MEMORY_BACKEND(obj);
  49
  50     m->share = true;
  51     m->merge = false;
  52     m->dump = false;
  53 }
  54
  55 static void sgx_epc_backend_class_init(ObjectClass *oc, void *data)
  56 {
  57     HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
  58
  59     bc->alloc = sgx_epc_backend_memory_alloc;
  60 }
  61
  62 static const TypeInfo sgx_epc_backed_info = {
  63     .name = TYPE_MEMORY_BACKEND_EPC,
  64     .parent = TYPE_MEMORY_BACKEND,
  65     .instance_init = sgx_epc_backend_instance_init,
  66     .class_init = sgx_epc_backend_class_init,
  67     .instance_size = sizeof(HostMemoryBackendEpc),
  68 };
  69
  70 static void register_types(void)
  71 {
  72     int fd = qemu_open_old("/dev/sgx_vepc", O_RDWR);
  73     if (fd >= 0) {
  74         close(fd);
  75
  76         type_register_static(&sgx_epc_backed_info);
  77     }
  78 }
  79
  80 type_init(register_types);