On 2018年04月04日 20:54, w...@redhat.com wrote:
From: Wei Xu
Signed-off-by: Wei Xu
---
hw/virtio/virtio.c | 104 +
1 file changed, 90 insertions(+), 14 deletions(-)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 95a4681..def07c6 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -26,6 +26,7 @@
#define AVAIL_DESC_PACKED(b) ((b) << 7)
#define USED_DESC_PACKED(b) ((b) << 15)
+#define VIRTQ_F_DESC_USED(w) (AVAIL_DESC_PACKED(w) | USED_DESC_PACKED(w))
/*
* The alignment to use between consumer and producer parts of vring.
@@ -636,19 +637,11 @@ bool virtqueue_rewind(VirtQueue *vq, unsigned int num)
}
/* Called within rcu_read_lock(). */
-void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
+static void virtqueue_fill_split(VirtQueue *vq, const VirtQueueElement *elem,
unsigned int len, unsigned int idx)
{
VRingUsedElem uelem;
-trace_virtqueue_fill(vq, elem, len, idx);
-
-virtqueue_unmap_sg(vq, elem, len);
-
-if (unlikely(vq->vdev->broken)) {
-return;
-}
-
if (unlikely(!vq->vring.used)) {
return;
}
@@ -660,16 +653,66 @@ void virtqueue_fill(VirtQueue *vq, const VirtQueueElement
*elem,
vring_used_write(vq, , idx);
}
-/* Called within rcu_read_lock(). */
-void virtqueue_flush(VirtQueue *vq, unsigned int count)
+static void virtqueue_fill_packed(VirtQueue *vq, const VirtQueueElement *elem)
{
-uint16_t old, new;
+uint16_t i, w, head;
+VRingMemoryRegionCaches *caches;
+VRingDescPacked desc = {
+.addr = 0,
+.flags = 0,
+};
+
+if (unlikely(!vq->packed.desc)) {
+return;
+}
+
+w = elem->wrap_counter;
+caches = vring_get_region_caches(vq);
+for (i = 0; i < elem->count; i++) {
+head = (elem->index + i) % vq->packed.num;
This looks strange, we should get the location from vq->used_idx.
+/* Don't toggle the first one since it is the originally one */
+if ((i > 0) && (!head)) {
+w ^= 1;
+}
+
+desc.id = elem->index;
+desc.flags = VIRTQ_F_DESC_USED(w);
+desc.len = elem->len[i];
This should be determined by the caller, especially for the WRITE
descriptor.
+virtio_tswap16s(vq->vdev, );
+virtio_tswap32s(vq->vdev, );
+virtio_tswap16s(vq->vdev, );
+address_space_write_cached(>desc,
+ sizeof(VRingDescPacked) * head, ,
+ sizeof(VRingDescPacked));
We should make sure flags is written after other fileds. So need a wmb()
between the two writes.
+address_space_cache_invalidate(>desc,
+ sizeof(VRingDescPacked) * head,
+ sizeof(VRingDescPacked));
+}
Have you tested the case when elem->count is greater than one? According
to the spec device only need to write a single used descriptor for the
whole list.
+}
+
+void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
+unsigned int len, unsigned int idx)
+{
+trace_virtqueue_fill(vq, elem, len, idx);
+
+virtqueue_unmap_sg(vq, elem, len);
if (unlikely(vq->vdev->broken)) {
-vq->inuse -= count;
return;
}
+if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
+virtqueue_fill_packed(vq, elem);
+} else {
+virtqueue_fill_split(vq, elem, len, idx);
+}
+}
+
+/* Called within rcu_read_lock(). */
+static void virtqueue_flush_split(VirtQueue *vq, unsigned int count)
+{
+uint16_t old, new;
+
if (unlikely(!vq->vring.used)) {
return;
}
@@ -685,12 +728,45 @@ void virtqueue_flush(VirtQueue *vq, unsigned int count)
vq->signalled_used_valid = false;
}
+static void virtqueue_flush_packed(VirtQueue *vq, unsigned int count)
+{
+if (unlikely(!vq->packed.desc)) {
+return;
+}
+
+vq->inuse -= count;
+
+/* FIXME: is this correct? */
+if (vq->inuse) {
+return;
+}
I think the semantics here is write flags here.
+}
+
+void virtqueue_flush(VirtQueue *vq, unsigned int count)
+{
+if (unlikely(vq->vdev->broken)) {
+vq->inuse -= count;
+return;
+}
+
+if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
+virtqueue_flush_packed(vq, count);
+} else {
+virtqueue_flush_split(vq, count);
+}
+}
+
void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
unsigned int len)
{
rcu_read_lock();
virtqueue_fill(vq, elem, len, 0);
-virtqueue_flush(vq, 1);
+if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
+/* FIXME: How to deal with the length field for chained desc */
+virtqueue_flush(vq, elem->count);
+} else {
+