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/*
* 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 <http://www.gnu.org/licenses/>.
*/
#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/device_tree.h"
#include "sysemu/rng.h"
#include "hw/ppc/spapr.h"
#include "hw/qdev-properties.h"
#include "kvm_ppc.h"
#include "qom/object.h"
OBJECT_DECLARE_SIMPLE_TYPE(SpaprRngState, SPAPR_RNG)
struct SpaprRngState {
/*< private >*/
DeviceState ds;
RngBackend *backend;
bool use_kvm;
};
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");
}
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);
device_class_set_props(dc, 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)
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