On 11/3/21 08:51, Andrew Jones wrote:
On Fri, Aug 27, 2021 at 12:17:18PM +0200, Pierre Morel wrote:
To communicate in both directions with a VIRTIO device we need
to add the incoming communication to the VIRTIO level.
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
---
lib/virtio.c | 32 ++++++++++++++++++++++++++++++++
lib/virtio.h | 2 ++
2 files changed, 34 insertions(+)
diff --git a/lib/virtio.c b/lib/virtio.c
index e10153b9..b84bc680 100644
--- a/lib/virtio.c
+++ b/lib/virtio.c
@@ -47,6 +47,38 @@ void vring_init_virtqueue(struct vring_virtqueue *vq, unsigned index,
vq->data[i] = NULL;
}
+int virtqueue_add_inbuf(struct virtqueue *_vq, char *buf, unsigned int len)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+ unsigned int avail;
+ int head;
+
+ assert(buf);
+ assert(len);
+
+ if (!vq->vq.num_free)
+ return -1;
+
+ --vq->vq.num_free;
+
+ head = vq->free_head;
+
+ vq->vring.desc[head].flags = 0;
+ vq->vring.desc[head].addr = virt_to_phys(buf);
+ vq->vring.desc[head].len = len;
+
+ vq->free_head = vq->vring.desc[head].next;
+
+ vq->data[head] = buf;
+
+ avail = (vq->vring.avail->idx & (vq->vring.num - 1));
+ vq->vring.avail->ring[avail] = head;
+ wmb(); /* be sure to update the ring before updating the idx */
+ vq->vring.avail->idx++;
+ vq->num_added++;
+
+ return 0;
+}
int virtqueue_add_outbuf(struct virtqueue *_vq, char *buf, unsigned int len)
{
struct vring_virtqueue *vq = to_vvq(_vq);
diff --git a/lib/virtio.h b/lib/virtio.h
index 2c31fdc7..44b727f8 100644
--- a/lib/virtio.h
+++ b/lib/virtio.h
@@ -141,6 +141,8 @@ extern void vring_init_virtqueue(struct vring_virtqueue *vq, unsigned index,
const char *name);
extern int virtqueue_add_outbuf(struct virtqueue *vq, char *buf,
unsigned int len);
+extern int virtqueue_add_inbuf(struct virtqueue *vq, char *buf,
+ unsigned int len);
extern bool virtqueue_kick(struct virtqueue *vq);
extern void detach_buf(struct vring_virtqueue *vq, unsigned head);
extern void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len);
--
2.25.1
Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
Thanks,
Pierre
--
Pierre Morel
IBM Lab Boeblingen
