[PATCH v6 10/26] virtio_ring: packed: implement virtqueue_reset_vring_packed()
From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Date: 2022-02-24 08:12:01
Also in:
bpf, kvm, linux-remoteproc, linux-s390, linux-um, platform-driver-x86, virtualization
Subsystem:
the rest, virtio core · Maintainers:
Linus Torvalds, "Michael S. Tsirkin", Jason Wang
virtio ring supports reset. Queue reset is divided into several stages. 1. notify device queue reset 2. vring release 3. attach new vring 4. notify device queue re-enable After the first step is completed, the vring reset operation can be performed. If the newly set vring num does not change, then just reset the vq related value. Otherwise, the vring will be released and the vring will be reallocated. And the vring will be attached to the vq. If this process fails, the function will exit, and the state of the vq will be the vring release state. You can call this function again to reallocate the vring. Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> --- drivers/virtio/virtio_ring.c | 46 ++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index a2e771263ea7..3ee2d0e17515 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c@@ -1886,6 +1886,8 @@ static int vring_virtqueue_attach_packed(struct vring_virtqueue *vq, static void vring_virtqueue_init_packed(struct vring_virtqueue *vq, struct virtio_device *vdev) { + vq->vq.reset = VIRTIO_VQ_RESET_STEP_NONE; + vq->we_own_ring = true; vq->broken = false; vq->last_used_idx = 0;
@@ -1969,6 +1971,50 @@ static struct virtqueue *vring_create_virtqueue_packed( return NULL; } +static int virtqueue_reset_vring_packed(struct virtqueue *_vq, u32 num) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + struct virtio_device *vdev = _vq->vdev; + struct vring_packed vring; + int err; + + if (num > _vq->num_max) + return -E2BIG; + + switch (vq->vq.reset) { + case VIRTIO_VQ_RESET_STEP_NONE: + return -ENOENT; + + case VIRTIO_VQ_RESET_STEP_VRING_ATTACH: + case VIRTIO_VQ_RESET_STEP_DEVICE: + if (vq->packed.vring.num == num || !num) + break; + + vring_free(_vq); + + fallthrough; + + case VIRTIO_VQ_RESET_STEP_VRING_RELEASE: + if (!num) + num = vq->packed.vring.num; + + err = vring_create_vring_packed(&vring, vdev, num); + if (err) + return -ENOMEM; + + err = vring_virtqueue_attach_packed(vq, &vring, vdev); + if (err) { + vring_free_vring_packed(&vring, vdev); + return -ENOMEM; + } + } + + vring_virtqueue_init_packed(vq, vdev); + vq->vq.reset = VIRTIO_VQ_RESET_STEP_VRING_ATTACH; + + return 0; +} + /* * Generic functions and exported symbols.
--
2.31.0