Message ID | 20190514162744.30398-3-lvivier@redhat.com |
---|---|
State | New |
Headers | show |
Series | rng-builtin: add an RNG backend thatuses qemu_guest_getrandom() | expand |
On 14/05/2019 18:27, Laurent Vivier wrote: > Add a new RNG backend using QEMU builtin getrandom function. > > It can be created and used with something like: > > ... -object rng-builtin,id=rng0 -device virtio-rng,rng=rng0 ... > > Reviewed-by: Richard Henderson <richard.henderson@linaro.org> > Reviewed-by: Markus Armbruster <armbru@redhat.com> > Signed-off-by: Laurent Vivier <lvivier@redhat.com> > --- > backends/Makefile.objs | 2 +- > backends/rng-builtin.c | 54 ++++++++++++++++++++++++++++++++++++++++++ > qemu-options.hx | 7 ++++++ > 3 files changed, 62 insertions(+), 1 deletion(-) > create mode 100644 backends/rng-builtin.c > > diff --git a/backends/Makefile.objs b/backends/Makefile.objs > index 981e8e122f2c..f0691116e86e 100644 > --- a/backends/Makefile.objs > +++ b/backends/Makefile.objs > @@ -1,4 +1,4 @@ > -common-obj-y += rng.o rng-egd.o > +common-obj-y += rng.o rng-egd.o rng-builtin.o > common-obj-$(CONFIG_POSIX) += rng-random.o > > common-obj-$(CONFIG_TPM) += tpm.o > diff --git a/backends/rng-builtin.c b/backends/rng-builtin.c > new file mode 100644 > index 000000000000..6b9543a7de87 > --- /dev/null > +++ b/backends/rng-builtin.c > @@ -0,0 +1,54 @@ > +/* > + * QEMU Builtin Random Number Generator Backend > + * > + * This work is licensed under the terms of the GNU GPL, version 2 or later. > + * See the COPYING file in the top-level directory. > + */ > + > +#include "qemu/osdep.h" > +#include "sysemu/rng.h" > +#include "qemu/main-loop.h" > +#include "qemu/guest-random.h" > + > +#define TYPE_RNG_BUILTIN "rng-builtin" > +#define RNG_BUILTIN(obj) OBJECT_CHECK(RngBuiltin, (obj), TYPE_RNG_BUILTIN) > + > +typedef struct RngBuiltin { > + RngBackend parent; > +} RngBuiltin; > + > +static void rng_builtin_request_entropy(RngBackend *b, RngRequest *req) > +{ > + RngBuiltin *s = RNG_BUILTIN(b); > + > + while (!QSIMPLEQ_EMPTY(&s->parent.requests)) { > + RngRequest *req = QSIMPLEQ_FIRST(&s->parent.requests); > + > + qemu_guest_getrandom_nofail(req->data, req->size); > + > + req->receive_entropy(req->opaque, req->data, req->size); > + > + rng_backend_finalize_request(&s->parent, req); > There is a problem here: rng_backend_request_entropy() calls rng_builtin_request_entropy() and then add the request to the queue parent.requests, so receive_entropy() is called only on the next call of rng_backend_request_entropy() (and parameter req is unused). Thanks, Laurent
diff --git a/backends/Makefile.objs b/backends/Makefile.objs index 981e8e122f2c..f0691116e86e 100644 --- a/backends/Makefile.objs +++ b/backends/Makefile.objs @@ -1,4 +1,4 @@ -common-obj-y += rng.o rng-egd.o +common-obj-y += rng.o rng-egd.o rng-builtin.o common-obj-$(CONFIG_POSIX) += rng-random.o common-obj-$(CONFIG_TPM) += tpm.o diff --git a/backends/rng-builtin.c b/backends/rng-builtin.c new file mode 100644 index 000000000000..6b9543a7de87 --- /dev/null +++ b/backends/rng-builtin.c @@ -0,0 +1,54 @@ +/* + * QEMU Builtin Random Number Generator Backend + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#include "qemu/osdep.h" +#include "sysemu/rng.h" +#include "qemu/main-loop.h" +#include "qemu/guest-random.h" + +#define TYPE_RNG_BUILTIN "rng-builtin" +#define RNG_BUILTIN(obj) OBJECT_CHECK(RngBuiltin, (obj), TYPE_RNG_BUILTIN) + +typedef struct RngBuiltin { + RngBackend parent; +} RngBuiltin; + +static void rng_builtin_request_entropy(RngBackend *b, RngRequest *req) +{ + RngBuiltin *s = RNG_BUILTIN(b); + + while (!QSIMPLEQ_EMPTY(&s->parent.requests)) { + RngRequest *req = QSIMPLEQ_FIRST(&s->parent.requests); + + qemu_guest_getrandom_nofail(req->data, req->size); + + req->receive_entropy(req->opaque, req->data, req->size); + + rng_backend_finalize_request(&s->parent, req); + } +} + +static void rng_builtin_class_init(ObjectClass *klass, void *data) +{ + RngBackendClass *rbc = RNG_BACKEND_CLASS(klass); + + rbc->request_entropy = rng_builtin_request_entropy; +} + +static const TypeInfo rng_builtin_info = { + .name = TYPE_RNG_BUILTIN, + .parent = TYPE_RNG_BACKEND, + .instance_size = sizeof(RngBuiltin), + .class_init = rng_builtin_class_init, +}; + +static void register_types(void) +{ + type_register_static(&rng_builtin_info); +} + +type_init(register_types); diff --git a/qemu-options.hx b/qemu-options.hx index 4df0ea3aed5c..dc82a8c7ea14 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -4280,6 +4280,13 @@ other options. The @option{share} boolean option is @var{on} by default with memfd. +@item -object rng-builtin,id=@var{id} + +Creates a random number generator backend which obtains entropy from +QEMU builtin functions. The @option{id} parameter is a unique ID that +will be used to reference this entropy backend from the @option{virtio-rng} +device. + @item -object rng-random,id=@var{id},filename=@var{/dev/random} Creates a random number generator backend which obtains entropy from