[Minios-devel] [UNIKRAFT PATCH 3/5] plat/drivers: Allocate virtqueue for virtio 9P

[Cristian Banu <cristb@xxxxxxxxx>]

This patch implements virtqueue allocation with a stubbed interrupt
handler for virtio 9P devices.

Signed-off-by: Cristian Banu <cristb@xxxxxxxxx>
---
 plat/drivers/virtio/virtio_9p.c | 57 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/plat/drivers/virtio/virtio_9p.c b/plat/drivers/virtio/virtio_9p.c
index 798ebe908a6c..ab3a1b1679de 100644
--- a/plat/drivers/virtio/virtio_9p.c
+++ b/plat/drivers/virtio/virtio_9p.c
@@ -32,6 +32,7 @@
  * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.
  */
 
+#include <inttypes.h>
 #include <uk/alloc.h>
 #include <uk/essentials.h>
 #include <virtio/virtio_bus.h>
@@ -39,6 +40,7 @@
 #include <uk/plat/spinlock.h>
 
 #define DRIVER_NAME    "virtio-9p"
+#define NUM_SEGMENTS   128 /** The number of virtqueue descriptors. */
 static struct uk_alloc *a;
 
 /* List of initialized virtio 9p devices. */
@@ -52,8 +54,56 @@ struct virtio_9p_device {
        char *tag;
        /* Entry within the virtio devices' list. */
        struct uk_list_head _list;
+       /* Virtqueue reference. */
+       struct virtqueue *vq;
+       /* Hw queue identifier. */
+       uint16_t hwvq_id;
 };
 
+static int virtio_9p_recv(struct virtqueue *vq __unused, void *priv __unused)
+{
+       return 0;
+}
+
+static int virtio_9p_vq_alloc(struct virtio_9p_device *d)
+{
+       int vq_avail = 0;
+       int rc = 0;
+       __u16 qdesc_size;
+
+       vq_avail = virtio_find_vqs(d->vdev, 1, &qdesc_size);
+       if (unlikely(vq_avail != 1)) {
+               uk_pr_err(DRIVER_NAME": Expected: %d queues, found %d\n",
+                         1, vq_avail);
+               rc = -ENOMEM;
+               goto exit;
+       }
+
+       d->hwvq_id = 0;
+       if (unlikely(qdesc_size != NUM_SEGMENTS)) {
+               uk_pr_err(DRIVER_NAME": Expected %d descriptors, found %d 
(virtqueue %"
+                         PRIu16")\n", NUM_SEGMENTS, qdesc_size, d->hwvq_id);
+               rc = -EINVAL;
+               goto exit;
+       }
+
+       d->vq = virtio_vqueue_setup(d->vdev,
+                                   d->hwvq_id,
+                                   qdesc_size,
+                                   virtio_9p_recv,
+                                   a);
+       if (unlikely(PTRISERR(d->vq))) {
+               uk_pr_err(DRIVER_NAME": Failed to set up virtqueue %"PRIu16"\n",
+                         d->hwvq_id);
+               rc = PTR2ERR(d->vq);
+       }
+
+       d->vq->priv = d;
+
+exit:
+       return rc;
+}
+
 static int virtio_9p_feature_negotiate(struct virtio_9p_device *d)
 {
        __u64 host_features;
@@ -107,6 +157,12 @@ static int virtio_9p_configure(struct virtio_9p_device *d)
                goto out_status_fail;
        }
 
+       rc = virtio_9p_vq_alloc(d);
+       if (rc) {
+               uk_pr_err(DRIVER_NAME": Could not allocate virtqueue\n");
+               goto out_status_fail;
+       }
+
        uk_pr_info(DRIVER_NAME": Configured: features=0x%lx tag=%s\n",
                        d->vdev->features, d->tag);
 out:
@@ -119,6 +175,7 @@ out_status_fail:
 
 static int virtio_9p_start(struct virtio_9p_device *d)
 {
+       virtqueue_intr_enable(d->vq);
        virtio_dev_drv_up(d->vdev);
        uk_pr_info(DRIVER_NAME": %s started\n", d->tag);
 
-- 
2.11.0


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