From: Jonah Palmer <jonah.palmer@oracle.com>
To: qemu-devel@nongnu.org
Cc: mst@redhat.com, raphael@enfabrica.net, kwolf@redhat.com,
hreitz@redhat.com, jasowang@redhat.com, pbonzini@redhat.com,
fam@euphon.net, eperezma@redhat.com, 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, jonah.palmer@oracle.com
Subject: [PATCH 4/6] virtio: virtqueue_ordered_flush - VIRTIO_F_IN_ORDER support
Date: Mon, 6 May 2024 11:04:26 -0400 [thread overview]
Message-ID: <20240506150428.1203387-5-jonah.palmer@oracle.com> (raw)
In-Reply-To: <20240506150428.1203387-1-jonah.palmer@oracle.com>
Add VIRTIO_F_IN_ORDER feature support for virtqueue_flush operations.
The goal of the virtqueue_flush operation when the VIRTIO_F_IN_ORDER
feature has been negotiated is to write elements to the used/descriptor
ring in-order and then update used_idx.
The function iterates through the VirtQueueElement used_elems array
in-order starting at vq->used_idx. If the element is valid (filled), the
element is written to the used/descriptor ring. This process continues
until we find an invalid (not filled) element.
If any elements were written, the used_idx is updated.
Tested-by: Lei Yang <leiyang@redhat.com>
Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
---
hw/virtio/virtio.c | 75 +++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 74 insertions(+), 1 deletion(-)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 064046b5e2..0efed2c88e 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -1006,6 +1006,77 @@ static void virtqueue_packed_flush(VirtQueue *vq, unsigned int count)
}
}
+static void virtqueue_ordered_flush(VirtQueue *vq)
+{
+ unsigned int i = vq->used_idx;
+ unsigned int ndescs = 0;
+ uint16_t old = vq->used_idx;
+ 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].filled) {
+ return;
+ }
+
+ /* Write first expected in-order element to used ring (split VQs) */
+ if (!packed) {
+ uelem.id = vq->used_elems[i].index;
+ uelem.len = vq->used_elems[i].len;
+ vring_used_write(vq, &uelem, i);
+ }
+
+ ndescs += vq->used_elems[i].ndescs;
+ i += ndescs;
+ if (i >= vq->vring.num) {
+ i -= vq->vring.num;
+ }
+
+ /* Search for more filled elements in-order */
+ while (vq->used_elems[i].filled) {
+ if (packed) {
+ virtqueue_packed_fill_desc(vq, &vq->used_elems[i], ndescs, false);
+ } else {
+ uelem.id = vq->used_elems[i].index;
+ uelem.len = vq->used_elems[i].len;
+ vring_used_write(vq, &uelem, i);
+ }
+
+ vq->used_elems[i].filled = false;
+ ndescs += vq->used_elems[i].ndescs;
+ 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 {
+ vring_used_idx_set(vq, i);
+ if (unlikely((int16_t)(i - vq->signalled_used) < (uint16_t)(i - old))) {
+ vq->signalled_used_valid = false;
+ }
+ }
+ vq->inuse -= ndescs;
+}
+
void virtqueue_flush(VirtQueue *vq, unsigned int count)
{
if (virtio_device_disabled(vq->vdev)) {
@@ -1013,7 +1084,9 @@ 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);
--
2.39.3
next prev parent reply other threads:[~2024-05-06 15:04 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
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 ` Jonah Palmer [this message]
2024-05-10 7:48 ` [PATCH 4/6] virtio: virtqueue_ordered_flush " 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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240506150428.1203387-5-jonah.palmer@oracle.com \
--to=jonah.palmer@oracle.com \
--cc=boris.ostrovsky@oracle.com \
--cc=eperezma@redhat.com \
--cc=fam@euphon.net \
--cc=hreitz@redhat.com \
--cc=jasowang@redhat.com \
--cc=kwolf@redhat.com \
--cc=leiyang@redhat.com \
--cc=mst@redhat.com \
--cc=pbonzini@redhat.com \
--cc=qemu-block@nongnu.org \
--cc=qemu-devel@nongnu.org \
--cc=raphael@enfabrica.net \
--cc=schalla@marvell.com \
--cc=si-wei.liu@oracle.com \
--cc=stefanha@redhat.com \
--cc=virtio-fs@lists.linux.dev \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).