| Message ID | 20220308123518.33800-18-xuanzhuo@linux.alibaba.com |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | virtio pci support VIRTIO_F_RING_RESET | expand |
在 2022/3/8 下午8:35, Xuan Zhuo 写道: > This patch implements virtio pci support for QUEUE RESET. > > Performing reset on a queue is divided into these steps: > > 1. virtio_reset_vq() - notify the device to reset the queue > 2. virtqueue_detach_unused_buf() - recycle the buffer submitted > 3. virtqueue_reset_vring() - reset the vring (may re-alloc) > 4. virtio_enable_resetq() - 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@linux.alibaba.com> > --- > drivers/virtio/virtio_pci_common.c | 8 +-- > drivers/virtio/virtio_pci_modern.c | 83 ++++++++++++++++++++++++++++++ > 2 files changed, 88 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) { > + 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..3c67d3607802 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 +202,82 @@ 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; > + unsigned int irq; > + > + 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 = VIRTIO_VQ_RESET_STEP_DEVICE; > + > + /* sync irq callback. */ > + if (vp_dev->intx_enabled) { > + irq = vp_dev->pci_dev->irq; > + > + } else { > + if (info->msix_vector == VIRTIO_MSI_NO_VECTOR) > + return 0; > + > + irq = pci_irq_vector(vp_dev->pci_dev, info->msix_vector); > + } > + > + synchronize_irq(irq); Synchronize_irq() is not sufficient here since it breaks the effort of the interrupt hardening which is done by commits: 080cd7c3ac87 virtio-pci: harden INTX interrupts 9e35276a5344 virtio_pci: harden MSI-X interrupts Unfortunately 080cd7c3ac87 introduces an issue that disable_irq() were used for the affinity managed irq but we're discussing a fix. > + > + 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 != VIRTIO_VQ_RESET_STEP_VRING_ATTACH) > + 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); Any reason we need to check queue_enable() here? Thanks > + vq->reset = VIRTIO_VQ_RESET_STEP_NONE; > + > + 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 +486,8 @@ 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 +506,8 @@ 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 */
On Wed, 9 Mar 2022 16:54:10 +0800, Jason Wang <jasowang@redhat.com> wrote: > > 在 2022/3/8 下午8:35, Xuan Zhuo 写道: > > This patch implements virtio pci support for QUEUE RESET. > > > > Performing reset on a queue is divided into these steps: > > > > 1. virtio_reset_vq() - notify the device to reset the queue > > 2. virtqueue_detach_unused_buf() - recycle the buffer submitted > > 3. virtqueue_reset_vring() - reset the vring (may re-alloc) > > 4. virtio_enable_resetq() - 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@linux.alibaba.com> > > --- > > drivers/virtio/virtio_pci_common.c | 8 +-- > > drivers/virtio/virtio_pci_modern.c | 83 ++++++++++++++++++++++++++++++ > > 2 files changed, 88 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) { > > + 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..3c67d3607802 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 +202,82 @@ 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; > > + unsigned int irq; > > + > > + 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 = VIRTIO_VQ_RESET_STEP_DEVICE; > > + > > + /* sync irq callback. */ > > + if (vp_dev->intx_enabled) { > > + irq = vp_dev->pci_dev->irq; > > + > > + } else { > > + if (info->msix_vector == VIRTIO_MSI_NO_VECTOR) > > + return 0; > > + > > + irq = pci_irq_vector(vp_dev->pci_dev, info->msix_vector); > > + } > > + > > + synchronize_irq(irq); > > > Synchronize_irq() is not sufficient here since it breaks the effort of > the interrupt hardening which is done by commits: > > 080cd7c3ac87 virtio-pci: harden INTX interrupts > 9e35276a5344 virtio_pci: harden MSI-X interrupts > > Unfortunately 080cd7c3ac87 introduces an issue that disable_irq() were > used for the affinity managed irq but we're discussing a fix. I need to understand it first. > > > > + > > + 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 != VIRTIO_VQ_RESET_STEP_VRING_ATTACH) > > + 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); > > > Any reason we need to check queue_enable() here? The purpose of this function is to enable a reset vq, so call queue_enable() to activate it. Thanks. > > Thanks > > > > + vq->reset = VIRTIO_VQ_RESET_STEP_NONE; > > + > > + 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 +486,8 @@ 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 +506,8 @@ 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 */ >
On Wed, 9 Mar 2022 16:54:10 +0800, Jason Wang <jasowang@redhat.com> wrote: > > 在 2022/3/8 下午8:35, Xuan Zhuo 写道: > > This patch implements virtio pci support for QUEUE RESET. > > > > Performing reset on a queue is divided into these steps: > > > > 1. virtio_reset_vq() - notify the device to reset the queue > > 2. virtqueue_detach_unused_buf() - recycle the buffer submitted > > 3. virtqueue_reset_vring() - reset the vring (may re-alloc) > > 4. virtio_enable_resetq() - 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@linux.alibaba.com> > > --- > > drivers/virtio/virtio_pci_common.c | 8 +-- > > drivers/virtio/virtio_pci_modern.c | 83 ++++++++++++++++++++++++++++++ > > 2 files changed, 88 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) { > > + 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..3c67d3607802 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 +202,82 @@ 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; > > + unsigned int irq; > > + > > + 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 = VIRTIO_VQ_RESET_STEP_DEVICE; > > + > > + /* sync irq callback. */ > > + if (vp_dev->intx_enabled) { > > + irq = vp_dev->pci_dev->irq; > > + > > + } else { > > + if (info->msix_vector == VIRTIO_MSI_NO_VECTOR) > > + return 0; > > + > > + irq = pci_irq_vector(vp_dev->pci_dev, info->msix_vector); > > + } > > + > > + synchronize_irq(irq); > > > Synchronize_irq() is not sufficient here since it breaks the effort of > the interrupt hardening which is done by commits: > > 080cd7c3ac87 virtio-pci: harden INTX interrupts > 9e35276a5344 virtio_pci: harden MSI-X interrupts > > Unfortunately 080cd7c3ac87 introduces an issue that disable_irq() were > used for the affinity managed irq but we're discussing a fix. > ok, I think disable_irq() is still used here. I want to determine the solution for this detail first. So I posted the code, I hope Jason can help confirm this point first. There are three situations in which vq corresponds to an interrupt 1. intx 2. msix: per vq vectors 2. msix: share irq Essentially can be divided into two categories: per vq vectors and share irq. For share irq is based on virtqueues to find vq, so I think it is safe as long as list_del() is executed under the protection of the lock. In the case of per vq vectors, disable_irq() is used. Thanks. +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; + unsigned int irq; + + 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); + 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 && msix_vec != VIRTIO_MSI_NO_VECTOR) + disable_irq(pci_irq_vector(vp_dev->pci_dev, info->msix_vector)); + + 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); + vq->reset = false; + + if (vp_dev->per_vq_vectors && msix_vec != VIRTIO_MSI_NO_VECTOR) + enable_irq(pci_irq_vector(vp_dev->pci_dev, info->msix_vector)); + + return 0; +}
在 2022/3/9 下午5:32, Xuan Zhuo 写道: > On Wed, 9 Mar 2022 16:54:10 +0800, Jason Wang <jasowang@redhat.com> wrote: >> 在 2022/3/8 下午8:35, Xuan Zhuo 写道: >>> This patch implements virtio pci support for QUEUE RESET. >>> >>> Performing reset on a queue is divided into these steps: >>> >>> 1. virtio_reset_vq() - notify the device to reset the queue >>> 2. virtqueue_detach_unused_buf() - recycle the buffer submitted >>> 3. virtqueue_reset_vring() - reset the vring (may re-alloc) >>> 4. virtio_enable_resetq() - 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@linux.alibaba.com> >>> --- >>> drivers/virtio/virtio_pci_common.c | 8 +-- >>> drivers/virtio/virtio_pci_modern.c | 83 ++++++++++++++++++++++++++++++ >>> 2 files changed, 88 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) { >>> + 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..3c67d3607802 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 +202,82 @@ 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; >>> + unsigned int irq; >>> + >>> + 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 = VIRTIO_VQ_RESET_STEP_DEVICE; >>> + >>> + /* sync irq callback. */ >>> + if (vp_dev->intx_enabled) { >>> + irq = vp_dev->pci_dev->irq; >>> + >>> + } else { >>> + if (info->msix_vector == VIRTIO_MSI_NO_VECTOR) >>> + return 0; >>> + >>> + irq = pci_irq_vector(vp_dev->pci_dev, info->msix_vector); >>> + } >>> + >>> + synchronize_irq(irq); >> >> Synchronize_irq() is not sufficient here since it breaks the effort of >> the interrupt hardening which is done by commits: >> >> 080cd7c3ac87 virtio-pci: harden INTX interrupts >> 9e35276a5344 virtio_pci: harden MSI-X interrupts >> >> Unfortunately 080cd7c3ac87 introduces an issue that disable_irq() were >> used for the affinity managed irq but we're discussing a fix. > I need to understand it first. > >> >>> + >>> + 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 != VIRTIO_VQ_RESET_STEP_VRING_ATTACH) >>> + 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); >> >> Any reason we need to check queue_enable() here? > The purpose of this function is to enable a reset vq, so call queue_enable() to > activate it. Ok, this is what spec mandate. Thanks > > Thanks. > >> Thanks >> >> >>> + vq->reset = VIRTIO_VQ_RESET_STEP_NONE; >>> + >>> + 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 +486,8 @@ 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 +506,8 @@ 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 */
在 2022/3/10 下午4:20, Xuan Zhuo 写道: > On Wed, 9 Mar 2022 16:54:10 +0800, Jason Wang <jasowang@redhat.com> wrote: >> 在 2022/3/8 下午8:35, Xuan Zhuo 写道: >>> This patch implements virtio pci support for QUEUE RESET. >>> >>> Performing reset on a queue is divided into these steps: >>> >>> 1. virtio_reset_vq() - notify the device to reset the queue >>> 2. virtqueue_detach_unused_buf() - recycle the buffer submitted >>> 3. virtqueue_reset_vring() - reset the vring (may re-alloc) >>> 4. virtio_enable_resetq() - 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@linux.alibaba.com> >>> --- >>> drivers/virtio/virtio_pci_common.c | 8 +-- >>> drivers/virtio/virtio_pci_modern.c | 83 ++++++++++++++++++++++++++++++ >>> 2 files changed, 88 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) { >>> + 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..3c67d3607802 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 +202,82 @@ 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; >>> + unsigned int irq; >>> + >>> + 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 = VIRTIO_VQ_RESET_STEP_DEVICE; >>> + >>> + /* sync irq callback. */ >>> + if (vp_dev->intx_enabled) { >>> + irq = vp_dev->pci_dev->irq; >>> + >>> + } else { >>> + if (info->msix_vector == VIRTIO_MSI_NO_VECTOR) >>> + return 0; >>> + >>> + irq = pci_irq_vector(vp_dev->pci_dev, info->msix_vector); >>> + } >>> + >>> + synchronize_irq(irq); >> >> Synchronize_irq() is not sufficient here since it breaks the effort of >> the interrupt hardening which is done by commits: >> >> 080cd7c3ac87 virtio-pci: harden INTX interrupts >> 9e35276a5344 virtio_pci: harden MSI-X interrupts >> >> Unfortunately 080cd7c3ac87 introduces an issue that disable_irq() were >> used for the affinity managed irq but we're discussing a fix. >> > > ok, I think disable_irq() is still used here. > > I want to determine the solution for this detail first. So I posted the code, I > hope Jason can help confirm this point first. > > There are three situations in which vq corresponds to an interrupt > > 1. intx > 2. msix: per vq vectors > 2. msix: share irq > > Essentially can be divided into two categories: per vq vectors and share irq. > > For share irq is based on virtqueues to find vq, so I think it is safe as long > as list_del() is executed under the protection of the lock. > > In the case of per vq vectors, disable_irq() is used. See the discussion here[1], disable_irq() could be problematic for the block and scsi device that using affinity managed irq. We're waiting for the IRQ maintainer to comment on a solution. Other looks sane. Thanks [1] https://lkml.org/lkml/2022/3/8/743 > > Thanks. > > +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; > + unsigned int irq; > + > + 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); > + 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 && msix_vec != VIRTIO_MSI_NO_VECTOR) > + disable_irq(pci_irq_vector(vp_dev->pci_dev, info->msix_vector)); > + > + 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); > + vq->reset = false; > + > + if (vp_dev->per_vq_vectors && msix_vec != VIRTIO_MSI_NO_VECTOR) > + enable_irq(pci_irq_vector(vp_dev->pci_dev, info->msix_vector)); > + > + return 0; > +} > >
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) { + 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..3c67d3607802 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 +202,82 @@ 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; + unsigned int irq; + + 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 = VIRTIO_VQ_RESET_STEP_DEVICE; + + /* sync irq callback. */ + if (vp_dev->intx_enabled) { + irq = vp_dev->pci_dev->irq; + + } else { + if (info->msix_vector == VIRTIO_MSI_NO_VECTOR) + return 0; + + irq = pci_irq_vector(vp_dev->pci_dev, info->msix_vector); + } + + synchronize_irq(irq); + + 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 != VIRTIO_VQ_RESET_STEP_VRING_ATTACH) + 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); + vq->reset = VIRTIO_VQ_RESET_STEP_NONE; + + 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 +486,8 @@ 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 +506,8 @@ 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 */
This patch implements virtio pci support for QUEUE RESET. Performing reset on a queue is divided into these steps: 1. virtio_reset_vq() - notify the device to reset the queue 2. virtqueue_detach_unused_buf() - recycle the buffer submitted 3. virtqueue_reset_vring() - reset the vring (may re-alloc) 4. virtio_enable_resetq() - 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@linux.alibaba.com> --- drivers/virtio/virtio_pci_common.c | 8 +-- drivers/virtio/virtio_pci_modern.c | 83 ++++++++++++++++++++++++++++++ 2 files changed, 88 insertions(+), 3 deletions(-)