1 /* 2 * QEMU sPAPR random number generator "device" for H_RANDOM hypercall 3 * 4 * Copyright 2015 Thomas Huth, Red Hat Inc. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, 9 * or (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include "qemu/error-report.h" 21 #include "sysemu/sysemu.h" 22 #include "sysemu/device_tree.h" 23 #include "sysemu/rng.h" 24 #include "hw/ppc/spapr.h" 25 #include "kvm_ppc.h" 26 27 #define SPAPR_RNG(obj) \ 28 OBJECT_CHECK(sPAPRRngState, (obj), TYPE_SPAPR_RNG) 29 30 struct sPAPRRngState { 31 /*< private >*/ 32 DeviceState ds; 33 RngBackend *backend; 34 bool use_kvm; 35 }; 36 typedef struct sPAPRRngState sPAPRRngState; 37 38 struct HRandomData { 39 QemuSemaphore sem; 40 union { 41 uint64_t v64; 42 uint8_t v8[8]; 43 } val; 44 int received; 45 }; 46 typedef struct HRandomData HRandomData; 47 48 /* Callback function for the RngBackend */ 49 static void random_recv(void *dest, const void *src, size_t size) 50 { 51 HRandomData *hrdp = dest; 52 53 if (src && size > 0) { 54 assert(size + hrdp->received <= sizeof(hrdp->val.v8)); 55 memcpy(&hrdp->val.v8[hrdp->received], src, size); 56 hrdp->received += size; 57 } 58 59 qemu_sem_post(&hrdp->sem); 60 } 61 62 /* Handler for the H_RANDOM hypercall */ 63 static target_ulong h_random(PowerPCCPU *cpu, sPAPRMachineState *spapr, 64 target_ulong opcode, target_ulong *args) 65 { 66 sPAPRRngState *rngstate; 67 HRandomData hrdata; 68 69 rngstate = SPAPR_RNG(object_resolve_path_type("", TYPE_SPAPR_RNG, NULL)); 70 71 if (!rngstate || !rngstate->backend) { 72 return H_HARDWARE; 73 } 74 75 qemu_sem_init(&hrdata.sem, 0); 76 hrdata.val.v64 = 0; 77 hrdata.received = 0; 78 79 qemu_mutex_unlock_iothread(); 80 while (hrdata.received < 8) { 81 rng_backend_request_entropy(rngstate->backend, 8 - hrdata.received, 82 random_recv, &hrdata); 83 qemu_sem_wait(&hrdata.sem); 84 } 85 qemu_mutex_lock_iothread(); 86 87 qemu_sem_destroy(&hrdata.sem); 88 args[0] = hrdata.val.v64; 89 90 return H_SUCCESS; 91 } 92 93 static void spapr_rng_instance_init(Object *obj) 94 { 95 sPAPRRngState *rngstate = SPAPR_RNG(obj); 96 97 if (object_resolve_path_type("", TYPE_SPAPR_RNG, NULL) != NULL) { 98 error_report("spapr-rng can not be instantiated twice!"); 99 return; 100 } 101 102 object_property_add_link(obj, "rng", TYPE_RNG_BACKEND, 103 (Object **)&rngstate->backend, 104 object_property_allow_set_link, 105 OBJ_PROP_LINK_UNREF_ON_RELEASE, NULL); 106 object_property_set_description(obj, "rng", 107 "ID of the random number generator backend", 108 NULL); 109 } 110 111 static void spapr_rng_realize(DeviceState *dev, Error **errp) 112 { 113 114 sPAPRRngState *rngstate = SPAPR_RNG(dev); 115 116 if (rngstate->use_kvm) { 117 if (kvmppc_enable_hwrng() == 0) { 118 return; 119 } 120 /* 121 * If user specified both, use-kvm and a backend, we fall back to 122 * the backend now. If not, provide an appropriate error message. 123 */ 124 if (!rngstate->backend) { 125 error_setg(errp, "Could not initialize in-kernel H_RANDOM call!"); 126 return; 127 } 128 } 129 130 if (rngstate->backend) { 131 spapr_register_hypercall(H_RANDOM, h_random); 132 } else { 133 error_setg(errp, "spapr-rng needs an RNG backend!"); 134 } 135 } 136 137 int spapr_rng_populate_dt(void *fdt) 138 { 139 int node; 140 int ret; 141 142 node = qemu_fdt_add_subnode(fdt, "/ibm,platform-facilities"); 143 if (node <= 0) { 144 return -1; 145 } 146 ret = fdt_setprop_string(fdt, node, "device_type", 147 "ibm,platform-facilities"); 148 ret |= fdt_setprop_cell(fdt, node, "#address-cells", 0x1); 149 ret |= fdt_setprop_cell(fdt, node, "#size-cells", 0x0); 150 151 node = fdt_add_subnode(fdt, node, "ibm,random-v1"); 152 if (node <= 0) { 153 return -1; 154 } 155 ret |= fdt_setprop_string(fdt, node, "compatible", "ibm,random"); 156 157 return ret ? -1 : 0; 158 } 159 160 static Property spapr_rng_properties[] = { 161 DEFINE_PROP_BOOL("use-kvm", sPAPRRngState, use_kvm, false), 162 DEFINE_PROP_END_OF_LIST(), 163 }; 164 165 static void spapr_rng_class_init(ObjectClass *oc, void *data) 166 { 167 DeviceClass *dc = DEVICE_CLASS(oc); 168 169 dc->realize = spapr_rng_realize; 170 set_bit(DEVICE_CATEGORY_MISC, dc->categories); 171 dc->props = spapr_rng_properties; 172 } 173 174 static const TypeInfo spapr_rng_info = { 175 .name = TYPE_SPAPR_RNG, 176 .parent = TYPE_DEVICE, 177 .instance_size = sizeof(sPAPRRngState), 178 .instance_init = spapr_rng_instance_init, 179 .class_init = spapr_rng_class_init, 180 }; 181 182 static void spapr_rng_register_type(void) 183 { 184 type_register_static(&spapr_rng_info); 185 } 186 type_init(spapr_rng_register_type) 187