diff options
author | Ladi Prosek <lprosek@redhat.com> | 2016-03-03 09:37:18 +0100 |
---|---|---|
committer | Timothy Pearson <tpearson@raptorengineering.com> | 2019-11-29 19:49:12 -0600 |
commit | 7e173b3565e5968eb31a0b438fb49617b45515bd (patch) | |
tree | ec3725a696f3708adb27daad34f0c69339fcdb2f | |
parent | 855f3d3b99a9267239732fa637699e58d64a2261 (diff) | |
download | hqemu-7e173b3565e5968eb31a0b438fb49617b45515bd.zip hqemu-7e173b3565e5968eb31a0b438fb49617b45515bd.tar.gz |
rng: add request queue support to rng-random
Requests are now created in the RngBackend parent class and the
code path is shared by both rng-egd and rng-random.
This commit fixes the rng-random implementation which processed
only one request at a time and simply discarded all but the most
recent one. In the guest this manifested as delayed completion
of reads from virtio-rng, i.e. a read was completed only after
another read was issued.
By switching rng-random to use the same request queue as rng-egd,
the unsafe stack-based allocation of the entropy buffer is
eliminated and replaced with g_malloc.
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Message-Id: <1456994238-9585-5-git-send-email-lprosek@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
-rw-r--r-- | backends/rng-egd.c | 16 | ||||
-rw-r--r-- | backends/rng-random.c | 43 | ||||
-rw-r--r-- | backends/rng.c | 13 | ||||
-rw-r--r-- | include/sysemu/rng.h | 3 |
4 files changed, 34 insertions, 41 deletions
diff --git a/backends/rng-egd.c b/backends/rng-egd.c index 8f2bd16..30332ed 100644 --- a/backends/rng-egd.c +++ b/backends/rng-egd.c @@ -27,20 +27,10 @@ typedef struct RngEgd char *chr_name; } RngEgd; -static void rng_egd_request_entropy(RngBackend *b, size_t size, - EntropyReceiveFunc *receive_entropy, - void *opaque) +static void rng_egd_request_entropy(RngBackend *b, RngRequest *req) { RngEgd *s = RNG_EGD(b); - RngRequest *req; - - req = g_malloc(sizeof(*req)); - - req->offset = 0; - req->size = size; - req->receive_entropy = receive_entropy; - req->opaque = opaque; - req->data = g_malloc(req->size); + size_t size = req->size; while (size > 0) { uint8_t header[2]; @@ -54,8 +44,6 @@ static void rng_egd_request_entropy(RngBackend *b, size_t size, size -= len; } - - s->parent.requests = g_slist_append(s->parent.requests, req); } static int rng_egd_chr_can_read(void *opaque) diff --git a/backends/rng-random.c b/backends/rng-random.c index 8cdad6a..a6cb385 100644 --- a/backends/rng-random.c +++ b/backends/rng-random.c @@ -22,10 +22,6 @@ struct RndRandom int fd; char *filename; - - EntropyReceiveFunc *receive_func; - void *opaque; - size_t size; }; /** @@ -38,36 +34,35 @@ struct RndRandom static void entropy_available(void *opaque) { RndRandom *s = RNG_RANDOM(opaque); - uint8_t buffer[s->size]; - ssize_t len; - len = read(s->fd, buffer, s->size); - if (len < 0 && errno == EAGAIN) { - return; - } - g_assert(len != -1); + while (s->parent.requests != NULL) { + RngRequest *req = s->parent.requests->data; + ssize_t len; + + len = read(s->fd, req->data, req->size); + if (len < 0 && errno == EAGAIN) { + return; + } + g_assert(len != -1); - s->receive_func(s->opaque, buffer, len); - s->receive_func = NULL; + req->receive_entropy(req->opaque, req->data, len); + rng_backend_finalize_request(&s->parent, req); + } + + /* We've drained all requests, the fd handler can be reset. */ qemu_set_fd_handler(s->fd, NULL, NULL, NULL); } -static void rng_random_request_entropy(RngBackend *b, size_t size, - EntropyReceiveFunc *receive_entropy, - void *opaque) +static void rng_random_request_entropy(RngBackend *b, RngRequest *req) { RndRandom *s = RNG_RANDOM(b); - if (s->receive_func) { - s->receive_func(s->opaque, NULL, 0); + if (s->parent.requests == NULL) { + /* If there are no pending requests yet, we need to + * install our fd handler. */ + qemu_set_fd_handler(s->fd, entropy_available, NULL, s); } - - s->receive_func = receive_entropy; - s->opaque = opaque; - s->size = size; - - qemu_set_fd_handler(s->fd, entropy_available, NULL, s); } static void rng_random_opened(RngBackend *b, Error **errp) diff --git a/backends/rng.c b/backends/rng.c index 014cb9d..277a41b 100644 --- a/backends/rng.c +++ b/backends/rng.c @@ -20,9 +20,20 @@ void rng_backend_request_entropy(RngBackend *s, size_t size, void *opaque) { RngBackendClass *k = RNG_BACKEND_GET_CLASS(s); + RngRequest *req; if (k->request_entropy) { - k->request_entropy(s, size, receive_entropy, opaque); + req = g_malloc(sizeof(*req)); + + req->offset = 0; + req->size = size; + req->receive_entropy = receive_entropy; + req->opaque = opaque; + req->data = g_malloc(req->size); + + k->request_entropy(s, req); + + s->requests = g_slist_append(s->requests, req); } } diff --git a/include/sysemu/rng.h b/include/sysemu/rng.h index 08a2eda..4fffd68 100644 --- a/include/sysemu/rng.h +++ b/include/sysemu/rng.h @@ -45,8 +45,7 @@ struct RngBackendClass { ObjectClass parent_class; - void (*request_entropy)(RngBackend *s, size_t size, - EntropyReceiveFunc *receive_entropy, void *opaque); + void (*request_entropy)(RngBackend *s, RngRequest *req); void (*opened)(RngBackend *s, Error **errp); }; |