180 lines
5.4 KiB
Diff
180 lines
5.4 KiB
Diff
From 60253ed1e6ec6d8e5ef2efe7bf755f475dce9956 Mon Sep 17 00:00:00 2001
|
|
From: Ladi Prosek <lprosek@redhat.com>
|
|
Date: Thu, 3 Mar 2016 09:37:18 +0100
|
|
Subject: [PATCH] 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>
|
|
---
|
|
backends/rng-egd.c | 16 ++--------------
|
|
backends/rng-random.c | 43 +++++++++++++++++++------------------------
|
|
backends/rng.c | 13 ++++++++++++-
|
|
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);
|
|
};
|
|
--
|
|
2.7.4
|
|
|