| 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/osdep.h" |
| 21 | #include "qapi/error.h" |
| 22 | #include "qemu/error-report.h" |
| 23 | #include "qemu/main-loop.h" |
| 24 | #include "qemu/module.h" |
| 25 | #include "system/device_tree.h" |
| 26 | #include "system/rng.h" |
| 27 | #include "hw/ppc/spapr.h" |
| 28 | #include "hw/core/qdev-properties.h" |
| 29 | #include "kvm_ppc.h" |
| 30 | #include "qom/object.h" |
| 31 | |
| 32 | OBJECT_DECLARE_SIMPLE_TYPE(SpaprRngState, SPAPR_RNG) |
| 33 | |
| 34 | struct SpaprRngState { |
| 35 | /*< private >*/ |
| 36 | DeviceState ds; |
| 37 | RngBackend *backend; |
| 38 | bool use_kvm; |
| 39 | }; |
| 40 | |
| 41 | struct HRandomData { |
| 42 | QemuSemaphore sem; |
| 43 | union { |
| 44 | uint64_t v64; |
| 45 | uint8_t v8[8]; |
| 46 | } val; |
| 47 | int received; |
| 48 | }; |
| 49 | typedef struct HRandomData HRandomData; |
| 50 | |
| 51 | /* Callback function for the RngBackend */ |
| 52 | static void random_recv(void *dest, const void *src, size_t size) |
| 53 | { |
| 54 | HRandomData *hrdp = dest; |
| 55 | |
| 56 | if (src && size > 0) { |
| 57 | assert(size + hrdp->received <= sizeof(hrdp->val.v8)); |
| 58 | memcpy(&hrdp->val.v8[hrdp->received], src, size); |
| 59 | hrdp->received += size; |
| 60 | } |
| 61 | |
| 62 | qemu_sem_post(&hrdp->sem); |
| 63 | } |
| 64 | |
| 65 | /* Handler for the H_RANDOM hypercall */ |
| 66 | static target_ulong h_random(PowerPCCPU *cpu, SpaprMachineState *spapr, |
| 67 | target_ulong opcode, target_ulong *args) |
| 68 | { |
| 69 | SpaprRngState *rngstate; |
| 70 | HRandomData hrdata; |
| 71 | |
| 72 | rngstate = SPAPR_RNG(object_resolve_path_type("", TYPE_SPAPR_RNG, NULL)); |
| 73 | |
| 74 | if (!rngstate || !rngstate->backend) { |
| 75 | return H_HARDWARE; |
| 76 | } |
| 77 | |
| 78 | qemu_sem_init(&hrdata.sem, 0); |
| 79 | hrdata.val.v64 = 0; |
| 80 | hrdata.received = 0; |
| 81 | |
| 82 | while (hrdata.received < 8) { |
| 83 | rng_backend_request_entropy(rngstate->backend, 8 - hrdata.received, |
| 84 | random_recv, &hrdata); |
| 85 | bql_unlock(); |
| 86 | qemu_sem_wait(&hrdata.sem); |
| 87 | bql_lock(); |
| 88 | } |
| 89 | |
| 90 | qemu_sem_destroy(&hrdata.sem); |
| 91 | args[0] = hrdata.val.v64; |
| 92 | |
| 93 | return H_SUCCESS; |
| 94 | } |
| 95 | |
| 96 | static void spapr_rng_instance_init(Object *obj) |
| 97 | { |
| 98 | if (object_resolve_path_type("", TYPE_SPAPR_RNG, NULL) != NULL) { |
| 99 | error_report("spapr-rng can not be instantiated twice!"); |
| 100 | return; |
| 101 | } |
| 102 | |
| 103 | object_property_set_description(obj, "rng", |
| 104 | "ID of the random number generator backend"); |
| 105 | } |
| 106 | |
| 107 | static void spapr_rng_realize(DeviceState *dev, Error **errp) |
| 108 | { |
| 109 | |
| 110 | SpaprRngState *rngstate = SPAPR_RNG(dev); |
| 111 | |
| 112 | if (rngstate->use_kvm) { |
| 113 | if (kvmppc_enable_hwrng() == 0) { |
| 114 | return; |
| 115 | } |
| 116 | /* |
| 117 | * If user specified both, use-kvm and a backend, we fall back to |
| 118 | * the backend now. If not, provide an appropriate error message. |
| 119 | */ |
| 120 | if (!rngstate->backend) { |
| 121 | error_setg(errp, "Could not initialize in-kernel H_RANDOM call!"); |
| 122 | return; |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | if (rngstate->backend) { |
| 127 | spapr_register_hypercall(H_RANDOM, h_random); |
| 128 | } else { |
| 129 | error_setg(errp, "spapr-rng needs an RNG backend!"); |
| 130 | } |
| 131 | } |
| 132 | |
| 133 | static const Property spapr_rng_properties[] = { |
| 134 | DEFINE_PROP_BOOL("use-kvm", SpaprRngState, use_kvm, false), |
| 135 | DEFINE_PROP_LINK("rng", SpaprRngState, backend, TYPE_RNG_BACKEND, |
| 136 | RngBackend *), |
| 137 | }; |
| 138 | |
| 139 | static void spapr_rng_class_init(ObjectClass *oc, const void *data) |
| 140 | { |
| 141 | DeviceClass *dc = DEVICE_CLASS(oc); |
| 142 | |
| 143 | dc->realize = spapr_rng_realize; |
| 144 | set_bit(DEVICE_CATEGORY_MISC, dc->categories); |
| 145 | device_class_set_props(dc, spapr_rng_properties); |
| 146 | dc->hotpluggable = false; |
| 147 | } |
| 148 | |
| 149 | static const TypeInfo spapr_rng_info = { |
| 150 | .name = TYPE_SPAPR_RNG, |
| 151 | .parent = TYPE_DEVICE, |
| 152 | .instance_size = sizeof(SpaprRngState), |
| 153 | .instance_init = spapr_rng_instance_init, |
| 154 | .class_init = spapr_rng_class_init, |
| 155 | }; |
| 156 | |
| 157 | static void spapr_rng_register_type(void) |
| 158 | { |
| 159 | type_register_static(&spapr_rng_info); |
| 160 | } |
| 161 | type_init(spapr_rng_register_type) |