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Re: [Qemu-devel] [PATCH 0/6] add paravirtualization hwrng support
From: |
Amit Shah |
Subject: |
Re: [Qemu-devel] [PATCH 0/6] add paravirtualization hwrng support |
Date: |
Mon, 29 Oct 2012 12:31:10 +0530 |
On (Fri) 26 Oct 2012 [09:43:34], Anthony Liguori wrote:
> Hi,
>
> This series implements the backend and frontend infrastructure for virtio-rng.
> This is similar to previous series sent out by both Amit and myself although
> it
> has been trimmed down considerably.
>
> In terms of backends, a file and EGD backend are supported. The file defaults
> to /dev/random based on the feedback from Peter. It's still possible to
> support
> /dev/urandom though as an entropy source by overriding the file name.
>
> I think this series is ready to merge.
I have a small diff to this series that I had merged in mine. Please
apply to your tree as well.
(Gets rid of savevm/loadvm complexities by using the new
virtqueue_get_avail_bytes(), fixes typos/whitespace in rng.h)
diff --git b/hw/virtio-rng.c a/hw/virtio-rng.c
index b7fb5e9..290b2b6 100644
--- b/hw/virtio-rng.c
+++ a/hw/virtio-rng.c
@@ -22,14 +22,9 @@ typedef struct VirtIORNG {
/* Only one vq - guest puts buffer(s) on it when it needs entropy */
VirtQueue *vq;
- VirtQueueElement elem;
- /* Config data for the device -- currently only chardev */
VirtIORNGConf *conf;
- /* Whether we've popped a vq element into 'elem' above */
- bool popped;
-
RngBackend *rng;
} VirtIORNG;
@@ -42,23 +37,19 @@ static bool is_guest_ready(VirtIORNG *vrng)
return false;
}
-static size_t pop_an_elem(VirtIORNG *vrng)
+static size_t get_request_size(VirtQueue *vq)
{
- size_t size;
+ unsigned int in, out;
- if (!vrng->popped && !virtqueue_pop(vrng->vq, &vrng->elem)) {
- return 0;
- }
- vrng->popped = true;
-
- size = iov_size(vrng->elem.in_sg, vrng->elem.in_num);
- return size;
+ virtqueue_get_avail_bytes(vq, &in, &out);
+ return in;
}
/* Send data from a char device over to the guest */
static void chr_read(void *opaque, const void *buf, size_t size)
{
VirtIORNG *vrng = opaque;
+ VirtQueueElement elem;
size_t len;
int offset;
@@ -68,27 +59,16 @@ static void chr_read(void *opaque, const void *buf, size_t
size)
offset = 0;
while (offset < size) {
- if (!pop_an_elem(vrng)) {
+ if (!virtqueue_pop(vrng->vq, &elem)) {
break;
}
- len = iov_from_buf(vrng->elem.in_sg, vrng->elem.in_num,
+ len = iov_from_buf(elem.in_sg, elem.in_num,
0, buf + offset, size - offset);
offset += len;
- virtqueue_push(vrng->vq, &vrng->elem, len);
- vrng->popped = false;
+ virtqueue_push(vrng->vq, &elem, len);
}
virtio_notify(&vrng->vdev, vrng->vq);
-
- /*
- * Lastly, if we had multiple elems queued by the guest, and we
- * didn't have enough data to fill them all, indicate we want more
- * data.
- */
- len = pop_an_elem(vrng);
- if (len) {
- rng_backend_request_entropy(vrng->rng, size, chr_read, vrng);
- }
}
static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
@@ -96,7 +76,7 @@ static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
VirtIORNG *vrng = DO_UPCAST(VirtIORNG, vdev, vdev);
size_t size;
- size = pop_an_elem(vrng);
+ size = get_request_size(vq);
if (size) {
rng_backend_request_entropy(vrng->rng, size, chr_read, vrng);
}
@@ -112,23 +92,6 @@ static void virtio_rng_save(QEMUFile *f, void *opaque)
VirtIORNG *vrng = opaque;
virtio_save(&vrng->vdev, f);
-
- qemu_put_byte(f, vrng->popped);
- if (vrng->popped) {
- int i;
-
- qemu_put_be32(f, vrng->elem.index);
-
- qemu_put_be32(f, vrng->elem.in_num);
- for (i = 0; i < vrng->elem.in_num; i++) {
- qemu_put_be64(f, vrng->elem.in_addr[i]);
- }
-
- qemu_put_be32(f, vrng->elem.out_num);
- for (i = 0; i < vrng->elem.out_num; i++) {
- qemu_put_be64(f, vrng->elem.out_addr[i]);
- }
- }
}
static int virtio_rng_load(QEMUFile *f, void *opaque, int version_id)
@@ -139,30 +102,6 @@ static int virtio_rng_load(QEMUFile *f, void *opaque, int
version_id)
return -EINVAL;
}
virtio_load(&vrng->vdev, f);
-
- vrng->popped = qemu_get_byte(f);
- if (vrng->popped) {
- int i;
-
- vrng->elem.index = qemu_get_be32(f);
-
- vrng->elem.in_num = qemu_get_be32(f);
- g_assert(vrng->elem.in_num < VIRTQUEUE_MAX_SIZE);
- for (i = 0; i < vrng->elem.in_num; i++) {
- vrng->elem.in_addr[i] = qemu_get_be64(f);
- }
-
- vrng->elem.out_num = qemu_get_be32(f);
- g_assert(vrng->elem.out_num < VIRTQUEUE_MAX_SIZE);
- for (i = 0; i < vrng->elem.out_num; i++) {
- vrng->elem.out_addr[i] = qemu_get_be64(f);
- }
-
- virtqueue_map_sg(vrng->elem.in_sg, vrng->elem.in_addr,
- vrng->elem.in_num, 1);
- virtqueue_map_sg(vrng->elem.out_sg, vrng->elem.out_addr,
- vrng->elem.out_num, 0);
- }
return 0;
}
@@ -195,7 +134,6 @@ VirtIODevice *virtio_rng_init(DeviceState *dev,
VirtIORNGConf *conf)
vrng->qdev = dev;
vrng->conf = conf;
- vrng->popped = false;
register_savevm(dev, "virtio-rng", -1, 1, virtio_rng_save,
virtio_rng_load, vrng);
diff --git b/include/qemu/rng.h a/include/qemu/rng.h
index 7e9d672..9836463 100644
--- b/include/qemu/rng.h
+++ a/include/qemu/rng.h
@@ -61,10 +61,10 @@ struct RngBackend
* This function is used by the front-end to request entropy from an entropy
* source. This function can be called multiple times before @receive_entropy
* is invoked with different values of @receive_entropy and @opaque. The
- * backend will queue each request and handle appropriate.
+ * backend will queue each request and handle appropriately.
*
* The backend does not need to pass the full amount of data to
@receive_entropy
- * but will pass at a value greater than 0.
+ * but will pass a a value greater than 0.
*/
void rng_backend_request_entropy(RngBackend *s, size_t size,
EntropyReceiveFunc *receive_entropy,
@@ -87,7 +87,7 @@ void rng_backend_cancel_requests(RngBackend *s);
*
* This function will open the backend if it is not already open. Calling this
* function on an already opened backend will not result in an error.
- */
+ */
void rng_backend_open(RngBackend *s, Error **errp);
#endif
Amit
- Re: [Qemu-devel] [PATCH 0/6] add paravirtualization hwrng support, (continued)
- Re: [Qemu-devel] [PATCH 0/6] add paravirtualization hwrng support, Paolo Bonzini, 2012/10/26
- Re: [Qemu-devel] [PATCH 0/6] add paravirtualization hwrng support, H. Peter Anvin, 2012/10/26
- Re: [Qemu-devel] [PATCH 0/6] add paravirtualization hwrng support, Paolo Bonzini, 2012/10/26
- Re: [Qemu-devel] [PATCH 0/6] add paravirtualization hwrng support, H. Peter Anvin, 2012/10/26
- Re: [Qemu-devel] [PATCH 0/6] add paravirtualization hwrng support, H. Peter Anvin, 2012/10/26
- Re: [Qemu-devel] [PATCH 0/6] add paravirtualization hwrng support, Paolo Bonzini, 2012/10/26
Re: [Qemu-devel] [PATCH 0/6] add paravirtualization hwrng support,
Amit Shah <=