在 2022/4/6 上午11:43, Xuan Zhuo 写道:
This patch implements virtio pci support for QUEUE RESET. Performing reset on a queue is divided into these steps: 1. notify the device to reset the queue 2. recycle the buffer submitted 3. reset the vring (may re-alloc) 4. mmap vring to device, and enable the queue This patch implements virtio_reset_vq(), virtio_enable_resetq() in the pci scenario. Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> --- drivers/virtio/virtio_pci_common.c | 8 +-- drivers/virtio/virtio_pci_modern.c | 84 ++++++++++++++++++++++++++++++ drivers/virtio/virtio_ring.c | 2 + include/linux/virtio.h | 1 + 4 files changed, 92 insertions(+), 3 deletions(-) diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c index fdbde1db5ec5..863d3a8a0956 100644 --- a/drivers/virtio/virtio_pci_common.c +++ b/drivers/virtio/virtio_pci_common.c @@ -248,9 +248,11 @@ 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) {
On which condition that we may hit this path?
+ 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 49a4493732cf..cb5d38f1c9c8 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 */@@ -199,6 +202,83 @@ static int vp_active_vq(struct virtqueue *vq, u16 msix_vec) return 0; }+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); + + /* For the case where vq has an exclusive irq, to prevent the irq from + * being received again and the pending irq, call disable_irq(). + * + * In the scenario based on shared interrupts, vq will be searched from + * the queue virtqueues. Since the previous list_del() has been deleted + * from the queue, it is impossible for vq to be called in this case. + * There is no need to close the corresponding interrupt. + */ + if (vp_dev->per_vq_vectors && info->msix_vector != VIRTIO_MSI_NO_VECTOR) + disable_irq(pci_irq_vector(vp_dev->pci_dev, info->msix_vector));
See the previous discussion and the revert of the first try to harden the interrupt. We probably can't use disable_irq() since it conflicts with the affinity managed IRQ that is used by some drivers.
We need to use synchonize_irq() and per virtqueue flag instead. As mentioned in previous patches, this could be done on top of my rework on the IRQ hardening .
+
+ vq->reset = true;
+
+ 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;
+ unsigned long flags, index;
+ int err;
+
+ if (!vq->reset)
+ return -EBUSY;
+
+ index = vq->index;
+ info = vp_dev->vqs[index];
+
+ /* check queue reset status */
+ if (vp_modern_get_queue_reset(mdev, index) != 1)
+ return -EBUSY;
+
+ err = vp_active_vq(vq, info->msix_vector);
+ if (err)
+ return err;
+
+ if (vq->callback) {
+ spin_lock_irqsave(&vp_dev->lock, flags);
+ list_add(&info->node, &vp_dev->virtqueues);
+ spin_unlock_irqrestore(&vp_dev->lock, flags);
+ } else {
+ INIT_LIST_HEAD(&info->node);
+ }
+
+ vp_modern_set_queue_enable(&vp_dev->mdev, index, true);
+
+ if (vp_dev->per_vq_vectors && info->msix_vector != VIRTIO_MSI_NO_VECTOR)
+ enable_irq(pci_irq_vector(vp_dev->pci_dev, info->msix_vector));
We had the same issue as disable_irq(). Thanks
+ + vq->reset = false; + + return 0; +} + static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector) { return vp_modern_config_vector(&vp_dev->mdev, vector); @@ -407,6 +487,8 @@ 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 = {@@ -425,6 +507,8 @@ 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 */diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 6250e19fc5bf..91937e21edca 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -2028,6 +2028,7 @@ static struct virtqueue *vring_create_virtqueue_packed( vq->vq.vdev = vdev; vq->vq.name = name; vq->vq.index = index; + vq->vq.reset = false; vq->notify = notify; vq->weak_barriers = weak_barriers;@@ -2508,6 +2509,7 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,vq->vq.vdev = vdev; vq->vq.name = name; vq->vq.index = index; + vq->vq.reset = false; vq->notify = notify; vq->weak_barriers = weak_barriers;diff --git a/include/linux/virtio.h b/include/linux/virtio.hindex c86ff02e0ca0..33ab003c5100 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -33,6 +33,7 @@ struct virtqueue { unsigned int num_free; unsigned int num_max; void *priv; + bool reset; };int virtqueue_add_outbuf(struct virtqueue *vq,
