From: Eugenio Perez Martin <eperezma@redhat.com>
To: Jonah Palmer <jonah.palmer@oracle.com>
Cc: qemu-devel@nongnu.org, mst@redhat.com, raphael@enfabrica.net,
kwolf@redhat.com, hreitz@redhat.com, jasowang@redhat.com,
pbonzini@redhat.com, fam@euphon.net, stefanha@redhat.com,
qemu-block@nongnu.org, schalla@marvell.com, leiyang@redhat.com,
virtio-fs@lists.linux.dev, si-wei.liu@oracle.com,
boris.ostrovsky@oracle.com
Subject: Re: [PATCH 2/6] virtio: virtqueue_pop - VIRTIO_F_IN_ORDER support
Date: Thu, 9 May 2024 15:13:19 +0200 [thread overview]
Message-ID: <CAJaqyWeASizkBEmef4Yo7Mv0hF2zKe2p627G4ZEgVG0kMkCCOg@mail.gmail.com> (raw)
In-Reply-To: <20240506150428.1203387-3-jonah.palmer@oracle.com>
On Mon, May 6, 2024 at 5:06 PM Jonah Palmer <jonah.palmer@oracle.com> wrote:
>
> Add VIRTIO_F_IN_ORDER feature support in virtqueue_split_pop and
> virtqueue_packed_pop.
>
> VirtQueueElements popped from the available/descritpor ring are added to
> the VirtQueue's used_elems array in-order and in the same fashion as
> they would be added the used and descriptor rings, respectively.
>
> This will allow us to keep track of the current order, what elements
> have been written, as well as an element's essential data after being
> processed.
>
> Tested-by: Lei Yang <leiyang@redhat.com>
> Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
> ---
> hw/virtio/virtio.c | 17 ++++++++++++++++-
> 1 file changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 893a072c9d..e6eb1bb453 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -1506,7 +1506,7 @@ 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, j, head, max;
> VRingMemoryRegionCaches *caches;
> MemoryRegionCache indirect_desc_cache;
> MemoryRegionCache *desc_cache;
> @@ -1539,6 +1539,8 @@ static void *virtqueue_split_pop(VirtQueue *vq, size_t sz)
> goto done;
> }
>
> + j = vq->last_avail_idx;
> +
> if (!virtqueue_get_head(vq, vq->last_avail_idx++, &head)) {
> goto done;
> }
> @@ -1630,6 +1632,12 @@ 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)) {
> + vq->used_elems[j].index = elem->index;
> + vq->used_elems[j].len = elem->len;
> + vq->used_elems[j].ndescs = elem->ndescs;
> + }
> +
> vq->inuse++;
>
> trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);
> @@ -1758,6 +1766,13 @@ 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;
> + }
> +
I suggest using a consistent style between packed and split: Either
always use vq->last_avail_idx or j. If you use j, please rename to
something more related to the usage, as j is usually for iterations.
In my opinion I think vq->last_avail_idx is better.
> vq->last_avail_idx += elem->ndescs;
> vq->inuse += elem->ndescs;
>
> --
> 2.39.3
>
next prev parent reply other threads:[~2024-05-09 13:14 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-06 15:04 [PATCH 0/6] virtio,vhost: Add VIRTIO_F_IN_ORDER support Jonah Palmer
2024-05-06 15:04 ` [PATCH 1/6] virtio: Add bool to VirtQueueElement Jonah Palmer
2024-05-09 12:32 ` Eugenio Perez Martin
2024-05-10 10:26 ` Jonah Palmer
2024-05-06 15:04 ` [PATCH 2/6] virtio: virtqueue_pop - VIRTIO_F_IN_ORDER support Jonah Palmer
2024-05-09 13:13 ` Eugenio Perez Martin [this message]
2024-05-10 10:52 ` Jonah Palmer
2024-05-06 15:04 ` [PATCH 3/6] virtio: virtqueue_ordered_fill " Jonah Palmer
2024-05-09 14:08 ` Eugenio Perez Martin
2024-05-10 12:01 ` Jonah Palmer
2024-05-06 15:04 ` [PATCH 4/6] virtio: virtqueue_ordered_flush " Jonah Palmer
2024-05-10 7:48 ` Eugenio Perez Martin
2024-05-10 13:07 ` Jonah Palmer
2024-05-06 15:04 ` [PATCH 5/6] vhost,vhost-user: Add VIRTIO_F_IN_ORDER to vhost feature bits Jonah Palmer
2024-05-06 15:04 ` [PATCH 6/6] virtio: Add VIRTIO_F_IN_ORDER property definition Jonah Palmer
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