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Message-ID: <CAJaqyWdmcaSAtGtXQAQ4sTD4S60+zHFpeyaS0YhRXxZOjV-+Pw@mail.gmail.com>
Date: Fri, 19 Dec 2025 16:18:51 +0100
From: Eugenio Perez Martin <eperezma@...hat.com>
To: Jason Wang <jasowang@...hat.com>
Cc: mst@...hat.com, xuanzhuo@...ux.alibaba.com, virtualization@...ts.linux.dev,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH V9 19/19] virtio_ring: add in order support
On Tue, Nov 25, 2025 at 8:10 AM Jason Wang <jasowang@...hat.com> wrote:
>
> This patch implements in order support for both split virtqueue and
> packed virtqueue. Performance could be gained for the device where the
> memory access could be expensive (e.g vhost-net or a real PCI device):
>
> Benchmark with KVM guest:
>
> Vhost-net on the host: (pktgen + XDP_DROP):
>
> in_order=off | in_order=on | +%
> TX: 4.51Mpps | 5.30Mpps | +17%
> RX: 3.47Mpps | 3.61Mpps | + 4%
>
> Vhost-user(testpmd) on the host: (pktgen/XDP_DROP):
>
> For split virtqueue:
>
> in_order=off | in_order=on | +%
> TX: 5.60Mpps | 5.60Mpps | +0.0%
> RX: 9.16Mpps | 9.61Mpps | +4.9%
>
> For packed virtqueue:
>
> in_order=off | in_order=on | +%
> TX: 5.60Mpps | 5.70Mpps | +1.7%
> RX: 10.6Mpps | 10.8Mpps | +1.8%
>
> Benchmark also shows no performance impact for in_order=off for queue
> size with 256 and 1024.
>
> Signed-off-by: Jason Wang <jasowang@...hat.com>
> ---
> drivers/virtio/virtio_ring.c | 458 +++++++++++++++++++++++++++++++++--
> 1 file changed, 435 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 61884e031b94..9847b23f82ea 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -70,6 +70,8 @@
> enum vq_layout {
> SPLIT = 0,
> PACKED,
> + SPLIT_IN_ORDER,
> + PACKED_IN_ORDER,
> VQ_TYPE_MAX,
> };
>
> @@ -80,6 +82,7 @@ struct vring_desc_state_split {
> * allocated together. So we won't stress more to the memory allocator.
> */
> struct vring_desc *indir_desc;
> + u32 total_len; /* Buffer Length */
> };
>
> struct vring_desc_state_packed {
> @@ -91,6 +94,7 @@ struct vring_desc_state_packed {
> struct vring_packed_desc *indir_desc;
> u16 num; /* Descriptor list length. */
> u16 last; /* The last desc state in a list. */
> + u32 total_len; /* Buffer Length */
> };
>
> struct vring_desc_extra {
> @@ -205,8 +209,24 @@ struct vring_virtqueue {
>
> enum vq_layout layout;
>
> - /* Head of free buffer list. */
> + /*
> + * Without IN_ORDER it's the head of free buffer list. With
> + * IN_ORDER and SPLIT, it's the next available buffer
> + * index. With IN_ORDER and PACKED, it's unused.
> + */
> unsigned int free_head;
> +
> + /*
> + * With IN_ORDER, once we see an in-order batch, this stores
> + * this last entry, and until we return the last buffer.
> + * After this, id is set to vq.num to mark it invalid.
s/vq.num/UINT_MAX/.
> + * Unused without IN_ORDER.
> + */
> + struct used_entry {
> + u32 id;
> + u32 len;
> + } batch_last;
> +
> /* Number we've added since last sync. */
> unsigned int num_added;
>
> @@ -218,6 +238,11 @@ struct vring_virtqueue {
> */
> u16 last_used_idx;
>
> + /* With IN_ORDER and SPLIT, last descriptor id we used to
> + * detach buffer.
> + */
> + u16 last_used;
> +
> /* Hint for event idx: already triggered no need to disable. */
> bool event_triggered;
>
> @@ -259,7 +284,12 @@ static void vring_free(struct virtqueue *_vq);
>
> static inline bool virtqueue_is_packed(const struct vring_virtqueue *vq)
> {
> - return vq->layout == PACKED;
> + return vq->layout == PACKED || vq->layout == PACKED_IN_ORDER;
> +}
> +
> +static inline bool virtqueue_is_in_order(const struct vring_virtqueue *vq)
> +{
> + return vq->layout == SPLIT_IN_ORDER || vq->layout == PACKED_IN_ORDER;
> }
>
> static bool virtqueue_use_indirect(const struct vring_virtqueue *vq,
> @@ -469,6 +499,8 @@ static void virtqueue_init(struct vring_virtqueue *vq, u32 num)
> else
> vq->last_used_idx = 0;
>
> + vq->last_used = 0;
> +
> vq->event_triggered = false;
> vq->num_added = 0;
>
> @@ -576,6 +608,8 @@ static inline int virtqueue_add_split(struct vring_virtqueue *vq,
> struct scatterlist *sg;
> struct vring_desc *desc;
> unsigned int i, n, avail, descs_used, err_idx, sg_count = 0;
> + /* Total length for in-order */
> + unsigned int total_len = 0;
> int head;
> bool indirect;
>
> @@ -648,6 +682,7 @@ static inline int virtqueue_add_split(struct vring_virtqueue *vq,
> */
> i = virtqueue_add_desc_split(vq, desc, extra, i, addr,
> len, flags ,premapped);
> + total_len += len;
> }
> }
> for (; n < (out_sgs + in_sgs); n++) {
> @@ -667,6 +702,7 @@ static inline int virtqueue_add_split(struct vring_virtqueue *vq,
> */
> i = virtqueue_add_desc_split(vq, desc, extra, i, addr,
> len, flags, premapped);
> + total_len += len;
> }
> }
>
> @@ -689,7 +725,12 @@ static inline int virtqueue_add_split(struct vring_virtqueue *vq,
> vq->vq.num_free -= descs_used;
>
> /* Update free pointer */
> - if (indirect)
> + if (virtqueue_is_in_order(vq)) {
> + vq->free_head += descs_used;
> + if (vq->free_head >= vq->split.vring.num)
> + vq->free_head -= vq->split.vring.num;
> + vq->split.desc_state[head].total_len = total_len;
> + } else if (indirect)
> vq->free_head = vq->split.desc_extra[head].next;
> else
> vq->free_head = i;
> @@ -862,6 +903,14 @@ static bool more_used_split(const struct vring_virtqueue *vq)
> return virtqueue_poll_split(vq, vq->last_used_idx);
> }
>
> +static bool more_used_split_in_order(const struct vring_virtqueue *vq)
> +{
> + if (vq->batch_last.id != UINT_MAX)
> + return true;
> +
> + return virtqueue_poll_split(vq, vq->last_used_idx);
> +}
> +
> static void *virtqueue_get_buf_ctx_split(struct vring_virtqueue *vq,
> unsigned int *len,
> void **ctx)
> @@ -919,6 +968,80 @@ static void *virtqueue_get_buf_ctx_split(struct vring_virtqueue *vq,
> return ret;
> }
>
> +static void *virtqueue_get_buf_ctx_split_in_order(struct vring_virtqueue *vq,
> + unsigned int *len,
> + void **ctx)
> +{
> + void *ret;
> + unsigned int num = vq->split.vring.num;
> + unsigned int num_free = vq->vq.num_free;
> + u16 last_used, last_used_idx;
> +
> + START_USE(vq);
> +
> + if (unlikely(vq->broken)) {
> + END_USE(vq);
> + return NULL;
> + }
> +
> + last_used = vq->last_used & (num - 1);
> + last_used_idx = vq->last_used_idx & (num - 1);
> +
> + if (vq->batch_last.id == UINT_MAX) {
> + if (!more_used_split_in_order(vq)) {
> + pr_debug("No more buffers in queue\n");
> + END_USE(vq);
> + return NULL;
> + }
> +
> + /*
> + * Only get used array entries after they have been
> + * exposed by host.
> + */
> + virtio_rmb(vq->weak_barriers);
> +
> + vq->batch_last.id = virtio32_to_cpu(vq->vq.vdev,
> + vq->split.vring.used->ring[last_used_idx].id);
> + vq->batch_last.len = virtio32_to_cpu(vq->vq.vdev,
> + vq->split.vring.used->ring[last_used_idx].len);
> + }
> +
> + if (vq->batch_last.id == last_used) {
> + vq->batch_last.id = UINT_MAX;
> + *len = vq->batch_last.len;
> + } else {
> + *len = vq->split.desc_state[last_used].total_len;
> + }
> +
> + if (unlikely(last_used >= num)) {
> + BAD_RING(vq, "id %u out of range\n", last_used);
> + return NULL;
> + }
> + if (unlikely(!vq->split.desc_state[last_used].data)) {
> + BAD_RING(vq, "id %u is not a head!\n", last_used);
> + return NULL;
> + }
> +
> + /* detach_buf_split clears data, so grab it now. */
> + ret = vq->split.desc_state[last_used].data;
> + detach_buf_split_in_order(vq, last_used, ctx);
> +
> + vq->last_used_idx++;
> + vq->last_used += (vq->vq.num_free - num_free);
> + /* If we expect an interrupt for the next entry, tell host
> + * by writing event index and flush out the write before
> + * the read in the next get_buf call. */
> + if (!(vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT))
> + virtio_store_mb(vq->weak_barriers,
> + &vring_used_event(&vq->split.vring),
> + cpu_to_virtio16(vq->vq.vdev, vq->last_used_idx));
> +
> + LAST_ADD_TIME_INVALID(vq);
> +
> + END_USE(vq);
> + return ret;
> +}
> +
> static void virtqueue_disable_cb_split(struct vring_virtqueue *vq)
> {
> if (!(vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) {
> @@ -1012,7 +1135,10 @@ static void *virtqueue_detach_unused_buf_split(struct vring_virtqueue *vq)
> continue;
> /* detach_buf_split clears data, so grab it now. */
> buf = vq->split.desc_state[i].data;
> - detach_buf_split(vq, i, NULL);
> + if (virtqueue_is_in_order(vq))
> + detach_buf_split_in_order(vq, i, NULL);
> + else
> + detach_buf_split(vq, i, NULL);
> vq->split.avail_idx_shadow--;
> vq->split.vring.avail->idx = cpu_to_virtio16(vq->vq.vdev,
> vq->split.avail_idx_shadow);
> @@ -1075,6 +1201,7 @@ static void virtqueue_vring_attach_split(struct vring_virtqueue *vq,
>
> /* Put everything in free lists. */
> vq->free_head = 0;
> + vq->batch_last.id = UINT_MAX;
> }
>
> static int vring_alloc_state_extra_split(struct vring_virtqueue_split *vring_split)
> @@ -1186,7 +1313,6 @@ static struct virtqueue *__vring_new_virtqueue_split(unsigned int index,
> if (!vq)
> return NULL;
>
> - vq->layout = SPLIT;
> vq->vq.callback = callback;
> vq->vq.vdev = vdev;
> vq->vq.name = name;
> @@ -1206,6 +1332,8 @@ static struct virtqueue *__vring_new_virtqueue_split(unsigned int index,
> vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) &&
> !context;
> vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
> + vq->layout = virtio_has_feature(vdev, VIRTIO_F_IN_ORDER) ?
> + SPLIT_IN_ORDER : SPLIT;
>
> if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
> vq->weak_barriers = false;
> @@ -1363,13 +1491,14 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
> unsigned int in_sgs,
> void *data,
> bool premapped,
> - gfp_t gfp)
> + gfp_t gfp,
> + u16 id)
> {
> struct vring_desc_extra *extra;
> struct vring_packed_desc *desc;
> struct scatterlist *sg;
> - unsigned int i, n, err_idx, len;
> - u16 head, id;
> + unsigned int i, n, err_idx, len, total_len = 0;
> + u16 head;
> dma_addr_t addr;
>
> head = vq->packed.next_avail_idx;
> @@ -1387,8 +1516,6 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
> }
>
> i = 0;
> - id = vq->free_head;
> - BUG_ON(id == vq->packed.vring.num);
>
> for (n = 0; n < out_sgs + in_sgs; n++) {
> for (sg = sgs[n]; sg; sg = sg_next(sg)) {
> @@ -1408,6 +1535,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
> extra[i].flags = n < out_sgs ? 0 : VRING_DESC_F_WRITE;
> }
>
> + total_len += len;
> i++;
> }
> }
> @@ -1454,13 +1582,15 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
> 1 << VRING_PACKED_DESC_F_USED;
> }
> vq->packed.next_avail_idx = n;
> - vq->free_head = vq->packed.desc_extra[id].next;
> + if (!virtqueue_is_in_order(vq))
> + vq->free_head = vq->packed.desc_extra[id].next;
>
> /* Store token and indirect buffer state. */
> vq->packed.desc_state[id].num = 1;
> vq->packed.desc_state[id].data = data;
> vq->packed.desc_state[id].indir_desc = desc;
> vq->packed.desc_state[id].last = id;
> + vq->packed.desc_state[id].total_len = total_len;
>
> vq->num_added += 1;
>
> @@ -1513,8 +1643,11 @@ static inline int virtqueue_add_packed(struct vring_virtqueue *vq,
> BUG_ON(total_sg == 0);
>
> if (virtqueue_use_indirect(vq, total_sg)) {
> + id = vq->free_head;
> + BUG_ON(id == vq->packed.vring.num);
> err = virtqueue_add_indirect_packed(vq, sgs, total_sg, out_sgs,
> - in_sgs, data, premapped, gfp);
> + in_sgs, data, premapped,
> + gfp, id);
> if (err != -ENOMEM) {
> END_USE(vq);
> return err;
> @@ -1635,6 +1768,156 @@ static inline int virtqueue_add_packed(struct vring_virtqueue *vq,
> return -EIO;
> }
>
> +static inline int virtqueue_add_packed_in_order(struct vring_virtqueue *vq,
> + struct scatterlist *sgs[],
> + unsigned int total_sg,
> + unsigned int out_sgs,
> + unsigned int in_sgs,
> + void *data,
> + void *ctx,
> + bool premapped,
> + gfp_t gfp)
> +{
> + struct vring_packed_desc *desc;
> + struct scatterlist *sg;
> + unsigned int i, n, sg_count, err_idx, total_len = 0;
> + __le16 head_flags, flags;
> + u16 head, avail_used_flags;
> + int err;
> +
> + START_USE(vq);
> +
> + BUG_ON(data == NULL);
> + BUG_ON(ctx && vq->indirect);
> +
> + if (unlikely(vq->broken)) {
> + END_USE(vq);
> + return -EIO;
> + }
> +
> + LAST_ADD_TIME_UPDATE(vq);
> +
> + BUG_ON(total_sg == 0);
> +
> + if (virtqueue_use_indirect(vq, total_sg)) {
> + err = virtqueue_add_indirect_packed(vq, sgs, total_sg, out_sgs,
> + in_sgs, data, premapped, gfp,
> + vq->packed.next_avail_idx);
> + if (err != -ENOMEM) {
> + END_USE(vq);
> + return err;
> + }
> +
> + /* fall back on direct */
> + }
> +
> + head = vq->packed.next_avail_idx;
> + avail_used_flags = vq->packed.avail_used_flags;
> +
> + WARN_ON_ONCE(total_sg > vq->packed.vring.num && !vq->indirect);
> +
> + desc = vq->packed.vring.desc;
> + i = head;
> +
> + if (unlikely(vq->vq.num_free < total_sg)) {
> + pr_debug("Can't add buf len %i - avail = %i\n",
> + total_sg, vq->vq.num_free);
> + END_USE(vq);
> + return -ENOSPC;
> + }
> +
> + sg_count = 0;
> + for (n = 0; n < out_sgs + in_sgs; n++) {
> + for (sg = sgs[n]; sg; sg = sg_next(sg)) {
> + dma_addr_t addr;
> + u32 len;
> +
> + flags = 0;
> + if (++sg_count != total_sg)
> + flags |= cpu_to_le16(VRING_DESC_F_NEXT);
> + if (n >= out_sgs)
> + flags |= cpu_to_le16(VRING_DESC_F_WRITE);
> +
> + if (vring_map_one_sg(vq, sg, n < out_sgs ?
> + DMA_TO_DEVICE : DMA_FROM_DEVICE,
> + &addr, &len, premapped))
> + goto unmap_release;
> +
> + flags |= cpu_to_le16(vq->packed.avail_used_flags);
> +
> + if (i == head)
> + head_flags = flags;
> + else
> + desc[i].flags = flags;
> +
> + desc[i].addr = cpu_to_le64(addr);
> + desc[i].len = cpu_to_le32(len);
> + desc[i].id = cpu_to_le16(head);
> +
> + if (unlikely(vq->use_map_api)) {
> + vq->packed.desc_extra[i].addr = premapped ?
> + DMA_MAPPING_ERROR: addr;
> + vq->packed.desc_extra[i].len = len;
> + vq->packed.desc_extra[i].flags =
> + le16_to_cpu(flags);
> + }
> +
> + if ((unlikely(++i >= vq->packed.vring.num))) {
> + i = 0;
> + vq->packed.avail_used_flags ^=
> + 1 << VRING_PACKED_DESC_F_AVAIL |
> + 1 << VRING_PACKED_DESC_F_USED;
> + vq->packed.avail_wrap_counter ^= 1;
> + }
> +
> + total_len += len;
> + }
> + }
> +
> + /* We're using some buffers from the free list. */
> + vq->vq.num_free -= total_sg;
> +
> + /* Update free pointer */
> + vq->packed.next_avail_idx = i;
> +
> + /* Store token. */
> + vq->packed.desc_state[head].num = total_sg;
> + vq->packed.desc_state[head].data = data;
> + vq->packed.desc_state[head].indir_desc = ctx;
> + vq->packed.desc_state[head].total_len = total_len;
> +
> + /*
> + * A driver MUST NOT make the first descriptor in the list
> + * available before all subsequent descriptors comprising
> + * the list are made available.
> + */
> + virtio_wmb(vq->weak_barriers);
> + vq->packed.vring.desc[head].flags = head_flags;
> + vq->num_added += total_sg;
> +
> + pr_debug("Added buffer head %i to %p\n", head, vq);
> + END_USE(vq);
> +
> + return 0;
> +
> +unmap_release:
> + err_idx = i;
> + i = head;
> + vq->packed.avail_used_flags = avail_used_flags;
> +
> + for (n = 0; n < total_sg; n++) {
> + if (i == err_idx)
> + break;
> + vring_unmap_extra_packed(vq, &vq->packed.desc_extra[i]);
> + i++;
> + if (i >= vq->packed.vring.num)
> + i = 0;
> + }
> +
> + END_USE(vq);
> + return -EIO;
> +}
> +
> static bool virtqueue_kick_prepare_packed(struct vring_virtqueue *vq)
> {
> u16 new, old, off_wrap, flags, wrap_counter, event_idx;
> @@ -1796,10 +2079,82 @@ static void update_last_used_idx_packed(struct vring_virtqueue *vq,
> cpu_to_le16(vq->last_used_idx));
> }
>
> +static bool more_used_packed_in_order(const struct vring_virtqueue *vq)
> +{
> + if (vq->batch_last.id != UINT_MAX)
> + return true;
> +
> + return virtqueue_poll_packed(vq, READ_ONCE(vq->last_used_idx));
> +}
> +
> +static void *virtqueue_get_buf_ctx_packed_in_order(struct vring_virtqueue *vq,
> + unsigned int *len,
> + void **ctx)
> +{
> + unsigned int num = vq->packed.vring.num;
> + u16 last_used, last_used_idx;
> + bool used_wrap_counter;
> + void *ret;
> +
> + START_USE(vq);
> +
> + if (unlikely(vq->broken)) {
> + END_USE(vq);
> + return NULL;
> + }
> +
> + last_used_idx = vq->last_used_idx;
> + used_wrap_counter = packed_used_wrap_counter(last_used_idx);
> + last_used = packed_last_used(last_used_idx);
> +
> + if (vq->batch_last.id == UINT_MAX) {
> + if (!more_used_packed_in_order(vq)) {
> + pr_debug("No more buffers in queue\n");
> + END_USE(vq);
> + return NULL;
> + }
> + /* Only get used elements after they have been exposed by host. */
> + virtio_rmb(vq->weak_barriers);
> + vq->batch_last.id =
> + le16_to_cpu(vq->packed.vring.desc[last_used].id);
> + vq->batch_last.len =
> + le32_to_cpu(vq->packed.vring.desc[last_used].len);
> + }
> +
> + if (vq->batch_last.id == last_used) {
> + vq->batch_last.id = UINT_MAX;
> + *len = vq->batch_last.len;
> + } else {
> + *len = vq->packed.desc_state[last_used].total_len;
> + }
> +
> + if (unlikely(last_used >= num)) {
> + BAD_RING(vq, "id %u out of range\n", last_used);
> + return NULL;
> + }
> + if (unlikely(!vq->packed.desc_state[last_used].data)) {
> + BAD_RING(vq, "id %u is not a head!\n", last_used);
> + return NULL;
> + }
> +
> + /* detach_buf_packed clears data, so grab it now. */
> + ret = vq->packed.desc_state[last_used].data;
> + detach_buf_packed_in_order(vq, last_used, ctx);
> +
> + update_last_used_idx_packed(vq, last_used, last_used,
> + used_wrap_counter);
> +
> + LAST_ADD_TIME_INVALID(vq);
> +
> + END_USE(vq);
> + return ret;
> +}
> +
> static void *virtqueue_get_buf_ctx_packed(struct vring_virtqueue *vq,
> unsigned int *len,
> void **ctx)
> {
> + unsigned int num = vq->packed.vring.num;
> u16 last_used, id, last_used_idx;
> bool used_wrap_counter;
> void *ret;
> @@ -1826,7 +2181,7 @@ static void *virtqueue_get_buf_ctx_packed(struct vring_virtqueue *vq,
> id = le16_to_cpu(vq->packed.vring.desc[last_used].id);
> *len = le32_to_cpu(vq->packed.vring.desc[last_used].len);
>
> - if (unlikely(id >= vq->packed.vring.num)) {
> + if (unlikely(id >= num)) {
> BAD_RING(vq, "id %u out of range\n", id);
> return NULL;
> }
> @@ -1967,7 +2322,10 @@ static void *virtqueue_detach_unused_buf_packed(struct vring_virtqueue *vq)
> continue;
> /* detach_buf clears data, so grab it now. */
> buf = vq->packed.desc_state[i].data;
> - detach_buf_packed(vq, i, NULL);
> + if (virtqueue_is_in_order(vq))
> + detach_buf_packed_in_order(vq, i, NULL);
> + else
> + detach_buf_packed(vq, i, NULL);
> END_USE(vq);
> return buf;
> }
> @@ -1993,6 +2351,8 @@ static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num)
> for (i = 0; i < num - 1; i++)
> desc_extra[i].next = i + 1;
>
> + desc_extra[num - 1].next = 0;
> +
> return desc_extra;
> }
>
> @@ -2124,10 +2484,17 @@ static void virtqueue_vring_attach_packed(struct vring_virtqueue *vq,
> {
> vq->packed = *vring_packed;
>
> - /* Put everything in free lists. */
> - vq->free_head = 0;
> + if (virtqueue_is_in_order(vq)) {
> + vq->batch_last.id = UINT_MAX;
> + } else {
> + /*
> + * Put everything in free lists. Note that
> + * next_avail_idx is sufficient with IN_ORDER so
> + * free_head is unused.
> + */
> + vq->free_head = 0;
> + }
> }
> -
> static void virtqueue_reset_packed(struct vring_virtqueue *vq)
> {
> memset(vq->packed.vring.device, 0, vq->packed.event_size_in_bytes);
> @@ -2172,13 +2539,14 @@ static struct virtqueue *__vring_new_virtqueue_packed(unsigned int index,
> #else
> vq->broken = false;
> #endif
> - vq->layout = PACKED;
> vq->map = map;
> vq->use_map_api = vring_use_map_api(vdev);
>
> vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) &&
> !context;
> vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
> + vq->layout = virtio_has_feature(vdev, VIRTIO_F_IN_ORDER) ?
> + PACKED_IN_ORDER : PACKED;
>
> if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
> vq->weak_barriers = false;
> @@ -2288,9 +2656,39 @@ static const struct virtqueue_ops packed_ops = {
> .reset = virtqueue_reset_packed,
> };
>
> +static const struct virtqueue_ops split_in_order_ops = {
> + .add = virtqueue_add_split,
> + .get = virtqueue_get_buf_ctx_split_in_order,
> + .kick_prepare = virtqueue_kick_prepare_split,
> + .disable_cb = virtqueue_disable_cb_split,
> + .enable_cb_delayed = virtqueue_enable_cb_delayed_split,
> + .enable_cb_prepare = virtqueue_enable_cb_prepare_split,
> + .poll = virtqueue_poll_split,
> + .detach_unused_buf = virtqueue_detach_unused_buf_split,
> + .more_used = more_used_split_in_order,
> + .resize = virtqueue_resize_split,
> + .reset = virtqueue_reset_split,
> +};
> +
> +static const struct virtqueue_ops packed_in_order_ops = {
> + .add = virtqueue_add_packed_in_order,
> + .get = virtqueue_get_buf_ctx_packed_in_order,
> + .kick_prepare = virtqueue_kick_prepare_packed,
> + .disable_cb = virtqueue_disable_cb_packed,
> + .enable_cb_delayed = virtqueue_enable_cb_delayed_packed,
> + .enable_cb_prepare = virtqueue_enable_cb_prepare_packed,
> + .poll = virtqueue_poll_packed,
> + .detach_unused_buf = virtqueue_detach_unused_buf_packed,
> + .more_used = more_used_packed_in_order,
> + .resize = virtqueue_resize_packed,
> + .reset = virtqueue_reset_packed,
> +};
> +
> static const struct virtqueue_ops *const all_ops[VQ_TYPE_MAX] = {
> [SPLIT] = &split_ops,
> - [PACKED] = &packed_ops
> + [PACKED] = &packed_ops,
> + [SPLIT_IN_ORDER] = &split_in_order_ops,
> + [PACKED_IN_ORDER] = &packed_in_order_ops,
> };
>
> static int virtqueue_disable_and_recycle(struct virtqueue *_vq,
> @@ -2346,6 +2744,12 @@ static int virtqueue_enable_after_reset(struct virtqueue *_vq)
> case PACKED: \
> ret = all_ops[PACKED]->op(vq, ##__VA_ARGS__); \
> break; \
> + case SPLIT_IN_ORDER: \
> + ret = all_ops[SPLIT_IN_ORDER]->op(vq, ##__VA_ARGS__); \
> + break; \
> + case PACKED_IN_ORDER: \
> + ret = all_ops[PACKED_IN_ORDER]->op(vq, ##__VA_ARGS__); \
> + break; \
> default: \
> BUG(); \
> break; \
> @@ -2362,10 +2766,16 @@ static int virtqueue_enable_after_reset(struct virtqueue *_vq)
> case PACKED: \
> all_ops[PACKED]->op(vq, ##__VA_ARGS__); \
> break; \
> - default: \
> - BUG(); \
> - break; \
> - } \
> + case SPLIT_IN_ORDER: \
> + all_ops[SPLIT_IN_ORDER]->op(vq, ##__VA_ARGS__); \
> + break; \
> + case PACKED_IN_ORDER: \
> + all_ops[PACKED_IN_ORDER]->op(vq, ##__VA_ARGS__); \
> + break; \
> + default: \
> + BUG(); \
> + break; \
> + } \
> })
>
> static inline int virtqueue_add(struct virtqueue *_vq,
> @@ -3081,6 +3491,8 @@ void vring_transport_features(struct virtio_device *vdev)
> break;
> case VIRTIO_F_NOTIFICATION_DATA:
> break;
> + case VIRTIO_F_IN_ORDER:
> + break;
> default:
> /* We don't understand this bit. */
> __virtio_clear_bit(vdev, i);
> --
> 2.31.1
>
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