diff options
Diffstat (limited to 'hw/virtio/virtio.c')
| -rw-r--r-- | hw/virtio/virtio.c | 131 |
1 files changed, 128 insertions, 3 deletions
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 583a224163..397c261c3c 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -872,6 +872,46 @@ static void virtqueue_packed_fill(VirtQueue *vq, const VirtQueueElement *elem, vq->used_elems[idx].ndescs = elem->ndescs; } +static void virtqueue_ordered_fill(VirtQueue *vq, const VirtQueueElement *elem, + unsigned int len) +{ + unsigned int i, steps, max_steps; + + i = vq->used_idx % vq->vring.num; + steps = 0; + /* + * We shouldn't need to increase 'i' by more than the distance + * between used_idx and last_avail_idx. + */ + max_steps = (vq->last_avail_idx - vq->used_idx) % vq->vring.num; + + /* Search for element in vq->used_elems */ + while (steps <= max_steps) { + /* Found element, set length and mark as filled */ + if (vq->used_elems[i].index == elem->index) { + vq->used_elems[i].len = len; + vq->used_elems[i].in_order_filled = true; + break; + } + + i += vq->used_elems[i].ndescs; + steps += vq->used_elems[i].ndescs; + + if (i >= vq->vring.num) { + i -= vq->vring.num; + } + } + + /* + * We should be able to find a matching VirtQueueElement in + * used_elems. If we don't, this is an error. + */ + if (steps >= max_steps) { + qemu_log_mask(LOG_GUEST_ERROR, "%s: %s cannot fill buffer id %u\n", + __func__, vq->vdev->name, elem->index); + } +} + static void virtqueue_packed_fill_desc(VirtQueue *vq, const VirtQueueElement *elem, unsigned int idx, @@ -922,7 +962,9 @@ void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem, return; } - if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) { + if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_IN_ORDER)) { + virtqueue_ordered_fill(vq, elem, len); + } else if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) { virtqueue_packed_fill(vq, elem, len, idx); } else { virtqueue_split_fill(vq, elem, len, idx); @@ -981,6 +1023,73 @@ static void virtqueue_packed_flush(VirtQueue *vq, unsigned int count) } } +static void virtqueue_ordered_flush(VirtQueue *vq) +{ + unsigned int i = vq->used_idx % vq->vring.num; + unsigned int ndescs = 0; + uint16_t old = vq->used_idx; + uint16_t new; + bool packed; + VRingUsedElem uelem; + + packed = virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED); + + if (packed) { + if (unlikely(!vq->vring.desc)) { + return; + } + } else if (unlikely(!vq->vring.used)) { + return; + } + + /* First expected in-order element isn't ready, nothing to do */ + if (!vq->used_elems[i].in_order_filled) { + return; + } + + /* Search for filled elements in-order */ + while (vq->used_elems[i].in_order_filled) { + /* + * First entry for packed VQs is written last so the guest + * doesn't see invalid descriptors. + */ + if (packed && i != vq->used_idx) { + virtqueue_packed_fill_desc(vq, &vq->used_elems[i], ndescs, false); + } else if (!packed) { + uelem.id = vq->used_elems[i].index; + uelem.len = vq->used_elems[i].len; + vring_used_write(vq, &uelem, i); + } + + vq->used_elems[i].in_order_filled = false; + ndescs += vq->used_elems[i].ndescs; + i += vq->used_elems[i].ndescs; + if (i >= vq->vring.num) { + i -= vq->vring.num; + } + } + + if (packed) { + virtqueue_packed_fill_desc(vq, &vq->used_elems[vq->used_idx], 0, true); + vq->used_idx += ndescs; + if (vq->used_idx >= vq->vring.num) { + vq->used_idx -= vq->vring.num; + vq->used_wrap_counter ^= 1; + vq->signalled_used_valid = false; + } + } else { + /* Make sure buffer is written before we update index. */ + smp_wmb(); + new = old + ndescs; + vring_used_idx_set(vq, new); + if (unlikely((int16_t)(new - vq->signalled_used) < + (uint16_t)(new - old))) { + vq->signalled_used_valid = false; + } + } + vq->inuse -= ndescs; +} + void virtqueue_flush(VirtQueue *vq, unsigned int count) { if (virtio_device_disabled(vq->vdev)) { @@ -988,7 +1097,9 @@ void virtqueue_flush(VirtQueue *vq, unsigned int count) return; } - if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) { + if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_IN_ORDER)) { + virtqueue_ordered_flush(vq); + } else if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) { virtqueue_packed_flush(vq, count); } else { virtqueue_split_flush(vq, count); @@ -1505,7 +1616,7 @@ static void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_nu static void *virtqueue_split_pop(VirtQueue *vq, size_t sz) { - unsigned int i, head, max; + unsigned int i, head, max, idx; VRingMemoryRegionCaches *caches; MemoryRegionCache indirect_desc_cache; MemoryRegionCache *desc_cache; @@ -1629,6 +1740,13 @@ static void *virtqueue_split_pop(VirtQueue *vq, size_t sz) elem->in_sg[i] = iov[out_num + i]; } + if (virtio_vdev_has_feature(vdev, VIRTIO_F_IN_ORDER)) { + idx = (vq->last_avail_idx - 1) % vq->vring.num; + vq->used_elems[idx].index = elem->index; + vq->used_elems[idx].len = elem->len; + vq->used_elems[idx].ndescs = elem->ndescs; + } + vq->inuse++; trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num); @@ -1762,6 +1880,13 @@ static void *virtqueue_packed_pop(VirtQueue *vq, size_t sz) elem->index = id; elem->ndescs = (desc_cache == &indirect_desc_cache) ? 1 : elem_entries; + + if (virtio_vdev_has_feature(vdev, VIRTIO_F_IN_ORDER)) { + vq->used_elems[vq->last_avail_idx].index = elem->index; + vq->used_elems[vq->last_avail_idx].len = elem->len; + vq->used_elems[vq->last_avail_idx].ndescs = elem->ndescs; + } + vq->last_avail_idx += elem->ndescs; vq->inuse += elem->ndescs; |