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virtio_pci_modern: use completion instead of busy loop to wait on admin cmd result

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Currently, the code waits in a busy loop on every admin virtqueue issued
command to get a reply. That prevents callers from issuing multiple
commands in parallel.

To overcome this limitation, introduce a virtqueue event callback for
admin virtqueue. For every issued command, use completion mechanism
to wait on a reply. In the event callback, trigger the completion
is done for every incoming reply.

Alongside with that, introduce a spin lock to protect the admin
virtqueue operations.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240716113552.80599-13-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Jiri Pirko
2024-07-16 13:35:51 +02:00
committed by Michael S. Tsirkin
parent 7090f2b5ad
commit 4c3b54af90
4 changed files with 78 additions and 17 deletions
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13
drivers/virtio/virtio_pci_common.c
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@@ -395,6 +395,8 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned int nvqs,
if (vqi->name && vqi->callback)
++nvectors;
}
if (avq_num && vector_policy == VP_VQ_VECTOR_POLICY_EACH)
++nvectors;
} else {
/* Second best: one for change, shared for all vqs. */
nvectors = 2;
@@ -425,9 +427,9 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned int nvqs,
if (!avq_num)
return 0;
sprintf(avq->name, "avq.%u", avq->vq_index);
vq = vp_find_one_vq_msix(vdev, avq->vq_index, NULL, avq->name, false,
true, &allocated_vectors, vector_policy,
&vp_dev->admin_vq.info);
vq = vp_find_one_vq_msix(vdev, avq->vq_index, vp_modern_avq_done,
avq->name, false, true, &allocated_vectors,
vector_policy, &vp_dev->admin_vq.info);
if (IS_ERR(vq)) {
err = PTR_ERR(vq);
goto error_find;
@@ -486,8 +488,9 @@ static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned int nvqs,
if (!avq_num)
return 0;
sprintf(avq->name, "avq.%u", avq->vq_index);
vq = vp_setup_vq(vdev, queue_idx++, NULL, avq->name, false,
VIRTIO_MSI_NO_VECTOR, &vp_dev->admin_vq.info);
vq = vp_setup_vq(vdev, queue_idx++, vp_modern_avq_done, avq->name,
false, VIRTIO_MSI_NO_VECTOR,
&vp_dev->admin_vq.info);
if (IS_ERR(vq)) {
err = PTR_ERR(vq);
goto out_del_vqs;