From 750cf86932cd16bd881bba372738c1c6f17fc189 Mon Sep 17 00:00:00 2001 From: Thomas Huth Date: Thu, 25 Feb 2016 13:44:20 +0100 Subject: [PATCH 1/6] MAINTAINERS: Add an entry for the include/sysemu/rng*.h files These headers are used by the virtio-rng and rng backends code, so they should be listed in the same section in MAINTAINERS, too. Signed-off-by: Thomas Huth Reviewed-by: Amit Shah Message-Id: <1456404260-26928-1-git-send-email-thuth@redhat.com> Signed-off-by: Amit Shah --- MAINTAINERS | 1 + 1 file changed, 1 insertion(+) diff --git a/MAINTAINERS b/MAINTAINERS index 13d1b4d81a..2f5a338218 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -921,6 +921,7 @@ M: Amit Shah S: Supported F: hw/virtio/virtio-rng.c F: include/hw/virtio/virtio-rng.h +F: include/sysemu/rng*.h F: backends/rng*.c nvme From 3c52ddcdc548e7fbe65112d8a7bdc9cd105b4750 Mon Sep 17 00:00:00 2001 From: Ladi Prosek Date: Thu, 3 Mar 2016 09:37:15 +0100 Subject: [PATCH 2/6] rng: remove the unused request cancellation code rng_backend_cancel_requests had no callers and none of the code deleted in this commit ever ran. Signed-off-by: Ladi Prosek Reviewed-by: Amit Shah Message-Id: <1456994238-9585-2-git-send-email-lprosek@redhat.com> Signed-off-by: Amit Shah --- backends/rng-egd.c | 12 ------------ backends/rng.c | 9 --------- include/sysemu/rng.h | 11 ----------- 3 files changed, 32 deletions(-) diff --git a/backends/rng-egd.c b/backends/rng-egd.c index 2de5cd5fef..0b2976ae45 100644 --- a/backends/rng-egd.c +++ b/backends/rng-egd.c @@ -125,17 +125,6 @@ static void rng_egd_free_requests(RngEgd *s) s->requests = NULL; } -static void rng_egd_cancel_requests(RngBackend *b) -{ - RngEgd *s = RNG_EGD(b); - - /* We simply delete the list of pending requests. If there is data in the - * queue waiting to be read, this is okay, because there will always be - * more data than we requested originally - */ - rng_egd_free_requests(s); -} - static void rng_egd_opened(RngBackend *b, Error **errp) { RngEgd *s = RNG_EGD(b); @@ -213,7 +202,6 @@ static void rng_egd_class_init(ObjectClass *klass, void *data) RngBackendClass *rbc = RNG_BACKEND_CLASS(klass); rbc->request_entropy = rng_egd_request_entropy; - rbc->cancel_requests = rng_egd_cancel_requests; rbc->opened = rng_egd_opened; } diff --git a/backends/rng.c b/backends/rng.c index b7820ef471..2f2f3ee4eb 100644 --- a/backends/rng.c +++ b/backends/rng.c @@ -26,15 +26,6 @@ void rng_backend_request_entropy(RngBackend *s, size_t size, } } -void rng_backend_cancel_requests(RngBackend *s) -{ - RngBackendClass *k = RNG_BACKEND_GET_CLASS(s); - - if (k->cancel_requests) { - k->cancel_requests(s); - } -} - static bool rng_backend_prop_get_opened(Object *obj, Error **errp) { RngBackend *s = RNG_BACKEND(obj); diff --git a/include/sysemu/rng.h b/include/sysemu/rng.h index 858be8cef4..87b3ebec99 100644 --- a/include/sysemu/rng.h +++ b/include/sysemu/rng.h @@ -37,7 +37,6 @@ struct RngBackendClass void (*request_entropy)(RngBackend *s, size_t size, EntropyReceiveFunc *receive_entropy, void *opaque); - void (*cancel_requests)(RngBackend *s); void (*opened)(RngBackend *s, Error **errp); }; @@ -68,14 +67,4 @@ struct RngBackend void rng_backend_request_entropy(RngBackend *s, size_t size, EntropyReceiveFunc *receive_entropy, void *opaque); - -/** - * rng_backend_cancel_requests: - * @s: the backend to cancel all pending requests in - * - * Cancels all pending requests submitted by @rng_backend_request_entropy. This - * should be used by a device during reset or in preparation for live migration - * to stop tracking any request. - */ -void rng_backend_cancel_requests(RngBackend *s); #endif From 74074e8a7c60592cf1cc6469dbc2550d24aeded3 Mon Sep 17 00:00:00 2001 From: Ladi Prosek Date: Thu, 3 Mar 2016 09:37:16 +0100 Subject: [PATCH 3/6] rng: move request queue from RngEgd to RngBackend The 'requests' field now lives in the RngBackend parent class. There are no functional changes in this commit. Signed-off-by: Ladi Prosek Reviewed-by: Amit Shah Message-Id: <1456994238-9585-3-git-send-email-lprosek@redhat.com> Signed-off-by: Amit Shah --- backends/rng-egd.c | 28 +++++++++------------------- include/sysemu/rng.h | 11 +++++++++++ 2 files changed, 20 insertions(+), 19 deletions(-) diff --git a/backends/rng-egd.c b/backends/rng-egd.c index 0b2976ae45..b061362e29 100644 --- a/backends/rng-egd.c +++ b/backends/rng-egd.c @@ -25,19 +25,8 @@ typedef struct RngEgd CharDriverState *chr; char *chr_name; - - GSList *requests; } RngEgd; -typedef struct RngRequest -{ - EntropyReceiveFunc *receive_entropy; - uint8_t *data; - void *opaque; - size_t offset; - size_t size; -} RngRequest; - static void rng_egd_request_entropy(RngBackend *b, size_t size, EntropyReceiveFunc *receive_entropy, void *opaque) @@ -66,7 +55,7 @@ static void rng_egd_request_entropy(RngBackend *b, size_t size, size -= len; } - s->requests = g_slist_append(s->requests, req); + s->parent.requests = g_slist_append(s->parent.requests, req); } static void rng_egd_free_request(RngRequest *req) @@ -81,7 +70,7 @@ static int rng_egd_chr_can_read(void *opaque) GSList *i; int size = 0; - for (i = s->requests; i; i = i->next) { + for (i = s->parent.requests; i; i = i->next) { RngRequest *req = i->data; size += req->size - req->offset; } @@ -94,8 +83,8 @@ static void rng_egd_chr_read(void *opaque, const uint8_t *buf, int size) RngEgd *s = RNG_EGD(opaque); size_t buf_offset = 0; - while (size > 0 && s->requests) { - RngRequest *req = s->requests->data; + while (size > 0 && s->parent.requests) { + RngRequest *req = s->parent.requests->data; int len = MIN(size, req->size - req->offset); memcpy(req->data + req->offset, buf + buf_offset, len); @@ -104,7 +93,8 @@ static void rng_egd_chr_read(void *opaque, const uint8_t *buf, int size) size -= len; if (req->offset == req->size) { - s->requests = g_slist_remove_link(s->requests, s->requests); + s->parent.requests = g_slist_remove_link(s->parent.requests, + s->parent.requests); req->receive_entropy(req->opaque, req->data, req->size); @@ -117,12 +107,12 @@ static void rng_egd_free_requests(RngEgd *s) { GSList *i; - for (i = s->requests; i; i = i->next) { + for (i = s->parent.requests; i; i = i->next) { rng_egd_free_request(i->data); } - g_slist_free(s->requests); - s->requests = NULL; + g_slist_free(s->parent.requests); + s->parent.requests = NULL; } static void rng_egd_opened(RngBackend *b, Error **errp) diff --git a/include/sysemu/rng.h b/include/sysemu/rng.h index 87b3ebec99..c744d82745 100644 --- a/include/sysemu/rng.h +++ b/include/sysemu/rng.h @@ -24,6 +24,7 @@ #define RNG_BACKEND_CLASS(klass) \ OBJECT_CLASS_CHECK(RngBackendClass, (klass), TYPE_RNG_BACKEND) +typedef struct RngRequest RngRequest; typedef struct RngBackendClass RngBackendClass; typedef struct RngBackend RngBackend; @@ -31,6 +32,15 @@ typedef void (EntropyReceiveFunc)(void *opaque, const void *data, size_t size); +struct RngRequest +{ + EntropyReceiveFunc *receive_entropy; + uint8_t *data; + void *opaque; + size_t offset; + size_t size; +}; + struct RngBackendClass { ObjectClass parent_class; @@ -47,6 +57,7 @@ struct RngBackend /*< protected >*/ bool opened; + GSList *requests; }; /** From 9f14b0add1dcdbfa2ee61051d068211fb0a1fcc9 Mon Sep 17 00:00:00 2001 From: Ladi Prosek Date: Thu, 3 Mar 2016 09:37:17 +0100 Subject: [PATCH 4/6] rng: move request queue cleanup from RngEgd to RngBackend RngBackend is now in charge of cleaning up the linked list on instance finalization. It also exposes a function to finalize individual RngRequest instances, called by its child classes. Signed-off-by: Ladi Prosek Reviewed-by: Amit Shah Message-Id: <1456994238-9585-4-git-send-email-lprosek@redhat.com> Signed-off-by: Amit Shah --- backends/rng-egd.c | 25 +------------------------ backends/rng.c | 32 ++++++++++++++++++++++++++++++++ include/sysemu/rng.h | 12 ++++++++++++ 3 files changed, 45 insertions(+), 24 deletions(-) diff --git a/backends/rng-egd.c b/backends/rng-egd.c index b061362e29..8f2bd16b18 100644 --- a/backends/rng-egd.c +++ b/backends/rng-egd.c @@ -58,12 +58,6 @@ static void rng_egd_request_entropy(RngBackend *b, size_t size, s->parent.requests = g_slist_append(s->parent.requests, req); } -static void rng_egd_free_request(RngRequest *req) -{ - g_free(req->data); - g_free(req); -} - static int rng_egd_chr_can_read(void *opaque) { RngEgd *s = RNG_EGD(opaque); @@ -93,28 +87,13 @@ static void rng_egd_chr_read(void *opaque, const uint8_t *buf, int size) size -= len; if (req->offset == req->size) { - s->parent.requests = g_slist_remove_link(s->parent.requests, - s->parent.requests); - req->receive_entropy(req->opaque, req->data, req->size); - rng_egd_free_request(req); + rng_backend_finalize_request(&s->parent, req); } } } -static void rng_egd_free_requests(RngEgd *s) -{ - GSList *i; - - for (i = s->parent.requests; i; i = i->next) { - rng_egd_free_request(i->data); - } - - g_slist_free(s->parent.requests); - s->parent.requests = NULL; -} - static void rng_egd_opened(RngBackend *b, Error **errp) { RngEgd *s = RNG_EGD(b); @@ -183,8 +162,6 @@ static void rng_egd_finalize(Object *obj) } g_free(s->chr_name); - - rng_egd_free_requests(s); } static void rng_egd_class_init(ObjectClass *klass, void *data) diff --git a/backends/rng.c b/backends/rng.c index 2f2f3ee4eb..014cb9d0fe 100644 --- a/backends/rng.c +++ b/backends/rng.c @@ -64,6 +64,30 @@ static void rng_backend_prop_set_opened(Object *obj, bool value, Error **errp) s->opened = true; } +static void rng_backend_free_request(RngRequest *req) +{ + g_free(req->data); + g_free(req); +} + +static void rng_backend_free_requests(RngBackend *s) +{ + GSList *i; + + for (i = s->requests; i; i = i->next) { + rng_backend_free_request(i->data); + } + + g_slist_free(s->requests); + s->requests = NULL; +} + +void rng_backend_finalize_request(RngBackend *s, RngRequest *req) +{ + s->requests = g_slist_remove(s->requests, req); + rng_backend_free_request(req); +} + static void rng_backend_init(Object *obj) { object_property_add_bool(obj, "opened", @@ -72,6 +96,13 @@ static void rng_backend_init(Object *obj) NULL); } +static void rng_backend_finalize(Object *obj) +{ + RngBackend *s = RNG_BACKEND(obj); + + rng_backend_free_requests(s); +} + static void rng_backend_class_init(ObjectClass *oc, void *data) { UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc); @@ -84,6 +115,7 @@ static const TypeInfo rng_backend_info = { .parent = TYPE_OBJECT, .instance_size = sizeof(RngBackend), .instance_init = rng_backend_init, + .instance_finalize = rng_backend_finalize, .class_size = sizeof(RngBackendClass), .class_init = rng_backend_class_init, .abstract = true, diff --git a/include/sysemu/rng.h b/include/sysemu/rng.h index c744d82745..08a2eda2a4 100644 --- a/include/sysemu/rng.h +++ b/include/sysemu/rng.h @@ -60,6 +60,7 @@ struct RngBackend GSList *requests; }; + /** * rng_backend_request_entropy: * @s: the backend to request entropy from @@ -78,4 +79,15 @@ struct RngBackend void rng_backend_request_entropy(RngBackend *s, size_t size, EntropyReceiveFunc *receive_entropy, void *opaque); + +/** + * rng_backend_free_request: + * @s: the backend that created the request + * @req: the request to finalize + * + * Used by child rng backend classes to finalize requests once they've been + * processed. The request is removed from the list of active requests and + * deleted. + */ +void rng_backend_finalize_request(RngBackend *s, RngRequest *req); #endif From 60253ed1e6ec6d8e5ef2efe7bf755f475dce9956 Mon Sep 17 00:00:00 2001 From: Ladi Prosek Date: Thu, 3 Mar 2016 09:37:18 +0100 Subject: [PATCH 5/6] 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 Reviewed-by: Amit Shah Message-Id: <1456994238-9585-5-git-send-email-lprosek@redhat.com> Signed-off-by: Amit Shah --- 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 8f2bd16b18..30332edb81 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 8cdad6af7b..a6cb3858e3 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; + 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); + + req->receive_entropy(req->opaque, req->data, len); + + rng_backend_finalize_request(&s->parent, req); } - g_assert(len != -1); - - s->receive_func(s->opaque, buffer, len); - s->receive_func = NULL; + /* 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 014cb9d0fe..277a41bb0f 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 08a2eda2a4..4fffd681a6 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); }; From f8693c2cd06d0401007b2c168126ab907f6da345 Mon Sep 17 00:00:00 2001 From: Ladi Prosek Date: Thu, 3 Mar 2016 10:48:34 +0100 Subject: [PATCH 6/6] virtio-rng: ask for more data if queue is not fully drained This commit effectively reverts: commit 4621c1768ef5d12171cca2aa1473595ecb9f1c9e Author: Amit Shah Date: Wed Nov 21 11:21:19 2012 +0530 virtio-rng: remove extra request for entropy but instead of calling virtio_rng_process unconditionally, it first checks to see if the queue is empty as a little bit of optimization. Signed-off-by: Ladi Prosek Reviewed-by: Amit Shah Message-Id: <1456998514-19271-1-git-send-email-lprosek@redhat.com> Signed-off-by: Amit Shah --- hw/virtio/virtio-rng.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/hw/virtio/virtio-rng.c b/hw/virtio/virtio-rng.c index 17da2f8f3d..d7134646e2 100644 --- a/hw/virtio/virtio-rng.c +++ b/hw/virtio/virtio-rng.c @@ -69,6 +69,13 @@ static void chr_read(void *opaque, const void *buf, size_t size) g_free(elem); } virtio_notify(vdev, vrng->vq); + + if (!virtio_queue_empty(vrng->vq)) { + /* If we didn't drain the queue, call virtio_rng_process + * to take care of asking for more data as appropriate. + */ + virtio_rng_process(vrng); + } } static void virtio_rng_process(VirtIORNG *vrng)