Merge tag 'pull-ppc-20211129' of https://github.com/legoater/qemu into staging
[qemu.git] / hw / ppc / spapr_rng.c
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 "sysemu/device_tree.h"
26 #include "sysemu/rng.h"
27 #include "hw/ppc/spapr.h"
28 #include "hw/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 qemu_mutex_unlock_iothread();
86 qemu_sem_wait(&hrdata.sem);
87 qemu_mutex_lock_iothread();
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 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 DEFINE_PROP_END_OF_LIST(),
138 };
139
140 static void spapr_rng_class_init(ObjectClass *oc, void *data)
141 {
142 DeviceClass *dc = DEVICE_CLASS(oc);
143
144 dc->realize = spapr_rng_realize;
145 set_bit(DEVICE_CATEGORY_MISC, dc->categories);
146 device_class_set_props(dc, spapr_rng_properties);
147 dc->hotpluggable = false;
148 }
149
150 static const TypeInfo spapr_rng_info = {
151 .name = TYPE_SPAPR_RNG,
152 .parent = TYPE_DEVICE,
153 .instance_size = sizeof(SpaprRngState),
154 .instance_init = spapr_rng_instance_init,
155 .class_init = spapr_rng_class_init,
156 };
157
158 static void spapr_rng_register_type(void)
159 {
160 type_register_static(&spapr_rng_info);
161 }
162 type_init(spapr_rng_register_type)