/* * QEMU sPAPR random number generator "device" for H_RANDOM hypercall * * Copyright 2015 Thomas Huth, Red Hat Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, * or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . */ #include "qemu/osdep.h" #include "qapi/error.h" #include "cpu.h" #include "qemu/error-report.h" #include "qemu/main-loop.h" #include "qemu/module.h" #include "sysemu/sysemu.h" #include "sysemu/device_tree.h" #include "sysemu/rng.h" #include "hw/ppc/spapr.h" #include "hw/qdev-properties.h" #include "kvm_ppc.h" #define SPAPR_RNG(obj) \ OBJECT_CHECK(SpaprRngState, (obj), TYPE_SPAPR_RNG) struct SpaprRngState { /*< private >*/ DeviceState ds; RngBackend *backend; bool use_kvm; }; typedef struct SpaprRngState SpaprRngState; struct HRandomData { QemuSemaphore sem; union { uint64_t v64; uint8_t v8[8]; } val; int received; }; typedef struct HRandomData HRandomData; /* Callback function for the RngBackend */ static void random_recv(void *dest, const void *src, size_t size) { HRandomData *hrdp = dest; if (src && size > 0) { assert(size + hrdp->received <= sizeof(hrdp->val.v8)); memcpy(&hrdp->val.v8[hrdp->received], src, size); hrdp->received += size; } qemu_sem_post(&hrdp->sem); } /* Handler for the H_RANDOM hypercall */ static target_ulong h_random(PowerPCCPU *cpu, SpaprMachineState *spapr, target_ulong opcode, target_ulong *args) { SpaprRngState *rngstate; HRandomData hrdata; rngstate = SPAPR_RNG(object_resolve_path_type("", TYPE_SPAPR_RNG, NULL)); if (!rngstate || !rngstate->backend) { return H_HARDWARE; } qemu_sem_init(&hrdata.sem, 0); hrdata.val.v64 = 0; hrdata.received = 0; while (hrdata.received < 8) { rng_backend_request_entropy(rngstate->backend, 8 - hrdata.received, random_recv, &hrdata); qemu_mutex_unlock_iothread(); qemu_sem_wait(&hrdata.sem); qemu_mutex_lock_iothread(); } qemu_sem_destroy(&hrdata.sem); args[0] = hrdata.val.v64; return H_SUCCESS; } static void spapr_rng_instance_init(Object *obj) { if (object_resolve_path_type("", TYPE_SPAPR_RNG, NULL) != NULL) { error_report("spapr-rng can not be instantiated twice!"); return; } object_property_set_description(obj, "rng", "ID of the random number generator backend", NULL); } static void spapr_rng_realize(DeviceState *dev, Error **errp) { SpaprRngState *rngstate = SPAPR_RNG(dev); if (rngstate->use_kvm) { if (kvmppc_enable_hwrng() == 0) { return; } /* * If user specified both, use-kvm and a backend, we fall back to * the backend now. If not, provide an appropriate error message. */ if (!rngstate->backend) { error_setg(errp, "Could not initialize in-kernel H_RANDOM call!"); return; } } if (rngstate->backend) { spapr_register_hypercall(H_RANDOM, h_random); } else { error_setg(errp, "spapr-rng needs an RNG backend!"); } } static Property spapr_rng_properties[] = { DEFINE_PROP_BOOL("use-kvm", SpaprRngState, use_kvm, false), DEFINE_PROP_LINK("rng", SpaprRngState, backend, TYPE_RNG_BACKEND, RngBackend *), DEFINE_PROP_END_OF_LIST(), }; static void spapr_rng_class_init(ObjectClass *oc, void *data) { DeviceClass *dc = DEVICE_CLASS(oc); dc->realize = spapr_rng_realize; set_bit(DEVICE_CATEGORY_MISC, dc->categories); dc->props = spapr_rng_properties; dc->hotpluggable = false; } static const TypeInfo spapr_rng_info = { .name = TYPE_SPAPR_RNG, .parent = TYPE_DEVICE, .instance_size = sizeof(SpaprRngState), .instance_init = spapr_rng_instance_init, .class_init = spapr_rng_class_init, }; static void spapr_rng_register_type(void) { type_register_static(&spapr_rng_info); } type_init(spapr_rng_register_type)