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

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@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];
+

+       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