From: Wei Xu <w...@redhat.com>
mostly as same as 1.0 except traversing all desc to feed
headcount, need a refactor.
Signed-off-by: Wei Xu <w...@redhat.com>
---
hw/virtio/virtio.c | 148 +++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 145 insertions(+), 3 deletions(-)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index bd669a2..cdbb5af 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -650,9 +650,9 @@ static int virtqueue_read_next_desc(VirtIODevice *vdev,
VRingDesc *desc,
return VIRTQUEUE_READ_DESC_MORE;
}
-void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
- unsigned int *out_bytes,
- unsigned max_in_bytes, unsigned max_out_bytes)
+static void virtqueue_split_get_avail_bytes(VirtQueue *vq,
+ unsigned int *in_bytes, unsigned int *out_bytes,
+ unsigned max_in_bytes, unsigned max_out_bytes)
{
VirtIODevice *vdev = vq->vdev;
unsigned int max, idx;
@@ -775,6 +775,148 @@ err:
goto done;
}
+static void virtqueue_packed_get_avail_bytes(VirtQueue *vq,
+ unsigned int *in_bytes, unsigned int *out_bytes,
+ unsigned max_in_bytes, unsigned max_out_bytes)
+{
+ VirtIODevice *vdev = vq->vdev;
+ unsigned int max, idx;
+ unsigned int total_bufs, in_total, out_total;
+ MemoryRegionCache *desc_cache;
+ VRingMemoryRegionCaches *caches;
+ MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
+ int64_t len = 0;
+ VRingDescPacked desc;
+
+ if (unlikely(!vq->vring.desc)) {
+ if (in_bytes) {
+ *in_bytes = 0;
+ }
+ if (out_bytes) {
+ *out_bytes = 0;
+ }
+ return;
+ }
+
+ rcu_read_lock();
+ idx = vq->last_avail_idx;
+ total_bufs = in_total = out_total = 0;
+
+ max = vq->vring.num;
+ caches = vring_get_region_caches(vq);
+ if (caches->desc.len < max * sizeof(VRingDescPacked)) {
+ virtio_error(vdev, "Cannot map descriptor ring");
+ goto err;
+ }
+
+ desc_cache = &caches->desc;
+ vring_packed_desc_read(vdev, &desc, desc_cache, idx);
+ while (is_desc_avail(&desc)) {
+ unsigned int num_bufs;
+ unsigned int i;
+
+ num_bufs = total_bufs;
+
+ if (desc.flags & VRING_DESC_F_INDIRECT) {
+ if (desc.len % sizeof(VRingDescPacked)) {
+ virtio_error(vdev, "Invalid size for indirect buffer table");
+ goto err;
+ }
+
+ /* If we've got too many, that implies a descriptor loop. */
+ if (num_bufs >= max) {
+ virtio_error(vdev, "Looped descriptor");
+ goto err;
+ }
+
+ /* loop over the indirect descriptor table */
+ len = address_space_cache_init(&indirect_desc_cache,
+ vdev->dma_as,
+ desc.addr, desc.len, false);
+ desc_cache = &indirect_desc_cache;
+ if (len < desc.len) {
+ virtio_error(vdev, "Cannot map indirect buffer");
+ goto err;
+ }
+
+ max = desc.len / sizeof(VRingDescPacked);
+ num_bufs = i = 0;
+ vring_packed_desc_read(vdev, &desc, desc_cache, i);
+ }
+
+ do {
+ /* If we've got too many, that implies a descriptor loop. */
+ if (++num_bufs > max) {
+ virtio_error(vdev, "Looped descriptor");
+ goto err;
+ }
+
+ if (desc.flags & VRING_DESC_F_WRITE) {
+ in_total += desc.len;
+ } else {
+ out_total += desc.len;
+ }
+ if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
+ goto done;
+ }
+
+ if (desc_cache == &indirect_desc_cache) {
+ if (++i >= vq->vring.num) {
+ i -= vq->vring.num;
+ }
+ vring_packed_desc_read(vdev, &desc, desc_cache, i);
+ } else {
+ if (++idx >= vq->vring.num) {
+ idx -= vq->vring.num;
+ }
+ vring_packed_desc_read(vdev, &desc, desc_cache, idx);
+ }
+ /* Make sure we see the flags */
+ smp_mb();
+ } while (desc.flags & VRING_DESC_F_NEXT);
+
+ if (desc_cache == &indirect_desc_cache) {
+ address_space_cache_destroy(&indirect_desc_cache);
+ total_bufs++;
+ /* We missed one step on for indirect desc */
+ idx++;
+ } else {
+ total_bufs = num_bufs;
+ }
+
+ desc_cache = &caches->desc;
+ vring_packed_desc_read(vdev, &desc, desc_cache, idx % vq->vring.num);
+ }
+
+done:
+ address_space_cache_destroy(&indirect_desc_cache);
+ if (in_bytes) {
+ *in_bytes = in_total;
+ }
+ if (out_bytes) {
+ *out_bytes = out_total;
+ }
+ rcu_read_unlock();
+ return;
+
+err:
+ in_total = out_total = 0;
+ goto done;
+}
+
+void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
+ unsigned int *out_bytes,
+ unsigned max_in_bytes, unsigned max_out_bytes)
+{
+ if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
+ virtqueue_packed_get_avail_bytes(vq, in_bytes, out_bytes,
+ max_in_bytes, max_out_bytes);
+ } else {
+ virtqueue_split_get_avail_bytes(vq, in_bytes, out_bytes,
+ max_in_bytes, max_out_bytes);
+ }
+}
+
int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,
unsigned int out_bytes)
{
--
1.8.3.1
