[PATCH v5 14/22] virtio_pci: queue_reset: support VIRTIO_F_RING_RESET

Xuan Zhuo
2022-02-14T08:14:08Z

This patch implements virtio pci support for QUEUE RESET.

Performing reset on a queue is divided into these steps:

1. reset_vq: reset one vq
2. recycle the buffer from vq by virtqueue_detach_unused_buf()
3. release the ring of the vq by vring_release_virtqueue()
4. enable_reset_vq: re-enable the reset queue

This patch implements reset_vq, enable_reset_vq in the pci scenario.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_pci_common.c |  8 ++--
 drivers/virtio/virtio_pci_modern.c | 60 ++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+), 3 deletions(-)

diff --git a/drivers/virtio/virtio_pci_common.c
b/drivers/virtio/virtio_pci_common.c
index 5a4f750a0b97..9ea319b1d404 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -255,9 +255,11 @@ static void vp_del_vq(struct virtqueue *vq)
 	struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index];
 	unsigned long flags;

-	spin_lock_irqsave(&vp_dev->lock, flags);
-	list_del(&info->node);
-	spin_unlock_irqrestore(&vp_dev->lock, flags);
+	if (!vq->reset) {
+		spin_lock_irqsave(&vp_dev->lock, flags);
+		list_del(&info->node);
+		spin_unlock_irqrestore(&vp_dev->lock, flags);
+	}

 	vp_dev->del_vq(info);
 	kfree(info);
diff --git a/drivers/virtio/virtio_pci_modern.c
b/drivers/virtio/virtio_pci_modern.c
index bed3e9b84272..7d28f4c36fc2 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -34,6 +34,9 @@ static void vp_transport_features(struct virtio_device *vdev,
u64 features)
 	if ((features & BIT_ULL(VIRTIO_F_SR_IOV)) &&
 			pci_find_ext_capability(pci_dev, PCI_EXT_CAP_ID_SRIOV))
 		__virtio_set_bit(vdev, VIRTIO_F_SR_IOV);
+
+	if (features & BIT_ULL(VIRTIO_F_RING_RESET))
+		__virtio_set_bit(vdev, VIRTIO_F_RING_RESET);
 }

 /* virtio config->finalize_features() implementation */
@@ -176,6 +179,59 @@ static void vp_reset(struct virtio_device *vdev)
 	vp_disable_cbs(vdev);
 }

+static int vp_modern_reset_vq(struct virtqueue *vq)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
+	struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
+	struct virtio_pci_vq_info *info;
+	unsigned long flags;
+
+	if (!virtio_has_feature(vq->vdev, VIRTIO_F_RING_RESET))
+		return -ENOENT;
+
+	vp_modern_set_queue_reset(mdev, vq->index);
+
+	info = vp_dev->vqs[vq->index];
+
+	/* delete vq from irq handler */
+	spin_lock_irqsave(&vp_dev->lock, flags);
+	list_del(&info->node);
+	spin_unlock_irqrestore(&vp_dev->lock, flags);
+
+	INIT_LIST_HEAD(&info->node);
+
+	vq->reset = VIRTQUEUE_RESET_STAGE_DEVICE;
+
+	return 0;
+}
+
+static int vp_modern_enable_reset_vq(struct virtqueue *vq)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
+	struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
+	struct virtio_pci_vq_info *info;
+	struct virtqueue *_vq;
+
+	if (vq->reset != VIRTQUEUE_RESET_STAGE_RELEASE)
+		return -EBUSY;
+
+	/* check queue reset status */
+	if (vp_modern_get_queue_reset(mdev, vq->index) != 1)
+		return -EBUSY;
+
+	info = vp_dev->vqs[vq->index];
+	_vq = vp_setup_vq(vq->vdev, vq->index, NULL, NULL, NULL,
+			 info->msix_vector);
+	if (IS_ERR(_vq)) {
+		vq->reset = VIRTQUEUE_RESET_STAGE_RELEASE;
+		return PTR_ERR(_vq);
+	}
+
+	vp_modern_set_queue_enable(&vp_dev->mdev, vq->index, true);
+
+	return 0;
+}
+
 static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
 {
 	return vp_modern_config_vector(&vp_dev->mdev, vector);
@@ -397,6 +453,8 @@ static const struct virtio_config_ops
virtio_pci_config_nodev_ops = {
 	.set_vq_affinity = vp_set_vq_affinity,
 	.get_vq_affinity = vp_get_vq_affinity,
 	.get_shm_region  = vp_get_shm_region,
+	.reset_vq	 = vp_modern_reset_vq,
+	.enable_reset_vq = vp_modern_enable_reset_vq,
 };

 static const struct virtio_config_ops virtio_pci_config_ops = {
@@ -415,6 +473,8 @@ static const struct virtio_config_ops virtio_pci_config_ops
= {
 	.set_vq_affinity = vp_set_vq_affinity,
 	.get_vq_affinity = vp_get_vq_affinity,
 	.get_shm_region  = vp_get_shm_region,
+	.reset_vq	 = vp_modern_reset_vq,
+	.enable_reset_vq = vp_modern_enable_reset_vq,
 };

 /* the PCI probing function */
--
2.31.0