thr3ads.net - Virtualization - [PATCH 5/6] virtio: queue_reset: pci: support VIRTIO_F_RING

If this information is useful, please help other people find it:
Share via:

Jason Wang

2022-Jan-19 06:11 UTC

[PATCH 5/6] virtio: queue_reset: pci: support VIRTIO_F_RING_RESET

On Wed, Jan 19, 2022 at 10:35 AM Xuan Zhuo <xuanzhuo at linux.alibaba.com>
wrote:>
> This patch implements virtio pci support for QUEUE RESET.
>
> Performing reset on a queue is divided into three steps:
>
> 1. reset_vq: notify the hardware queue to reset
> 2. del_reset_vq: delete the reset queue
> 3. enable_reset_vq: re-enable the reset queue
>
> Between steps 1 and 2, generally call virtqueue_detach_unused_buf() to
> recycle the buffer.
I wonder if it's better to squash 1, 2 and
virtqueue_detach_unused_buf() into a single helper.
>
> When deleting a vq, vp_del_vq() will be called to release all the memory
> of the vq. But this does not affect the process of deleting vqs, because
> that is based on the queue to release all the vqs. During this process,
> the vq has been removed from the queue.
>
> When deleting vq, info and vq will be released, and I save msix_vec in
> vp_dev->vqs[queue_index]. When re-enable, the current msix_vec can be
> reused. And based on intx_enabled to determine which method to use to
> enable this queue.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
> ---
>  drivers/virtio/virtio_pci_common.c | 54 ++++++++++++++++++++
>  drivers/virtio/virtio_pci_common.h |  5 ++
>  drivers/virtio/virtio_pci_modern.c | 81 ++++++++++++++++++++++++++++++
>  include/linux/virtio_config.h      | 21 ++++++++
>  4 files changed, 161 insertions(+)
>
> diff --git a/drivers/virtio/virtio_pci_common.c
b/drivers/virtio/virtio_pci_common.c
> index 5afe207ce28a..615a5a5f757c 100644
> --- a/drivers/virtio/virtio_pci_common.c
> +++ b/drivers/virtio/virtio_pci_common.c
> @@ -464,6 +464,60 @@ int vp_find_vqs(struct virtio_device *vdev, unsigned
nvqs,
>         return vp_find_vqs_intx(vdev, nvqs, vqs, callbacks, names, ctx);
>  }
>
> +#define VQ_IS_DELETED(vp_dev, idx) ((unsigned long)vp_dev->vqs[idx]
& 1)
> +#define VQ_RESET_MSIX_VEC(vp_dev, idx) ((unsigned long)vp_dev->vqs[idx]
>> 2)
> +#define VQ_RESET_MARK(msix_vec) ((void *)(long)((msix_vec << 2) +
1))
> +
> +int vp_del_reset_vq(struct virtio_device *vdev, u16 queue_index)
> +{
> +       struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +       struct virtio_pci_vq_info *info;
> +       u16 msix_vec;
> +
> +       if (VQ_IS_DELETED(vp_dev, queue_index))
> +               return -EPERM;
> +
> +       info = vp_dev->vqs[queue_index];
> +
> +       msix_vec = info->msix_vector;
> +
> +       /* delete vq */
> +       vp_del_vq(info->vq);
> +
> +       /* Mark the vq has been deleted, and save the msix_vec. */
> +       vp_dev->vqs[queue_index] = VQ_RESET_MARK(msix_vec);
> +
> +       return 0;
> +}
> +
> +struct virtqueue *vp_enable_reset_vq(struct virtio_device *vdev,
> +                                    int queue_index,
> +                                    vq_callback_t *callback,
> +                                    const char *name,
> +                                    const bool ctx)
> +{
> +       struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +       struct virtqueue *vq;
> +       u16 msix_vec;
> +
> +       if (!VQ_IS_DELETED(vp_dev, queue_index))
> +               return ERR_PTR(-EPERM);
> +
> +       msix_vec = VQ_RESET_MSIX_VEC(vp_dev, queue_index);
> +
> +       if (vp_dev->intx_enabled)
> +               vq = vp_setup_vq(vdev, queue_index, callback, name, ctx,
> +                                VIRTIO_MSI_NO_VECTOR);
> +       else
> +               vq = vp_enable_vq_msix(vdev, queue_index, callback, name,
ctx,
> +                                      msix_vec);
> +
> +       if (IS_ERR(vq))
> +               vp_dev->vqs[queue_index] = VQ_RESET_MARK(msix_vec);
> +
> +       return vq;
> +}
> +
>  const char *vp_bus_name(struct virtio_device *vdev)
>  {
>         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> diff --git a/drivers/virtio/virtio_pci_common.h
b/drivers/virtio/virtio_pci_common.h
> index 23f6c5c678d5..a92c99cc010e 100644
> --- a/drivers/virtio/virtio_pci_common.h
> +++ b/drivers/virtio/virtio_pci_common.h
> @@ -115,6 +115,11 @@ int vp_find_vqs(struct virtio_device *vdev, unsigned
nvqs,
>                 struct virtqueue *vqs[], vq_callback_t *callbacks[],
>                 const char * const names[], const bool *ctx,
>                 struct irq_affinity *desc);
> +void vp_reset_vq(struct virtio_device *vdev, u16 queue_index);
> +int vp_del_reset_vq(struct virtio_device *vdev, u16 queue_index);
> +struct virtqueue *vp_enable_reset_vq(struct virtio_device *vdev, int
queue_index,
> +                                    vq_callback_t *callback, const char
*name,
> +                                    const bool ctx);
>  const char *vp_bus_name(struct virtio_device *vdev);
>
>  /* Setup the affinity for a virtqueue:
> diff --git a/drivers/virtio/virtio_pci_modern.c
b/drivers/virtio/virtio_pci_modern.c
> index 5455bc041fb6..74e0b2b2f4dc 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 +179,78 @@ static void vp_reset(struct virtio_device *vdev)
>         vp_disable_cbs(vdev);
>  }
>
> +static int vp_modern_reset_vq(struct virtio_device *vdev, u16 queue_index)
> +{
> +       struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +       struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
> +       u16 msix_vec;
> +
> +       if (!virtio_has_feature(vdev, VIRTIO_F_RING_RESET))
> +               return -ENOENT;
> +
> +       vp_modern_set_queue_reset(mdev, queue_index);
> +
> +       /* After write 1 to queue reset, the driver MUST wait for a read of
> +        * queue reset to return 1.
> +        */
> +       while (vp_modern_get_queue_reset(mdev, queue_index) != 1)
> +               msleep(1);
> +
> +       msix_vec = vp_dev->vqs[queue_index]->msix_vector;
> +
> +       /* Disable VQ callback. */
> +       if (vp_dev->per_vq_vectors && msix_vec !=
VIRTIO_MSI_NO_VECTOR)
> +               disable_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec));
What happens if the irq is shared among virtqueues?
> +
> +       return 0;
> +}
> +
> +static int vp_modern_del_reset_vq(struct virtio_device *vdev, u16
queue_index)
> +{
> +       struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +       struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
> +
> +       if (!virtio_has_feature(vdev, VIRTIO_F_RING_RESET))
> +               return -ENOENT;
> +
> +       /* check queue reset status */
> +       if (vp_modern_get_queue_reset(mdev, queue_index) != 1)
> +               return -EBUSY;
> +
> +       return vp_del_reset_vq(vdev, queue_index);
> +}
> +
> +static struct virtqueue *vp_modern_enable_reset_vq(struct virtio_device
*vdev,
> +                                                  u16 queue_index,
> +                                                  vq_callback_t *callback,
> +                                                  const char *name,
> +                                                  const bool *ctx)
> +{
> +       struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +       struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
> +       struct virtqueue *vq;
> +       u16 msix_vec;
> +
> +       if (!virtio_has_feature(vdev, VIRTIO_F_RING_RESET))
> +               return ERR_PTR(-ENOENT);
> +
> +       /* check queue reset status */
> +       if (vp_modern_get_queue_reset(mdev, queue_index) != 1)
> +               return ERR_PTR(-EBUSY);
> +
> +       vq = vp_enable_reset_vq(vdev, queue_index, callback, name, ctx);
> +       if (IS_ERR(vq))
> +               return vq;
> +
> +       vp_modern_set_queue_enable(&vp_dev->mdev, vq->index,
true);
> +
> +       msix_vec = vp_dev->vqs[queue_index]->msix_vector;
> +       if (vp_dev->per_vq_vectors && msix_vec !=
VIRTIO_MSI_NO_VECTOR)
> +               enable_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec));
> +
> +       return vq;
> +}
> +
>  static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
>  {
>         return vp_modern_config_vector(&vp_dev->mdev, vector);
> @@ -395,6 +470,9 @@ 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,
> +       .del_reset_vq    = vp_modern_del_reset_vq,
> +       .enable_reset_vq = vp_modern_enable_reset_vq,
>  };
>
>  static const struct virtio_config_ops virtio_pci_config_ops = {
> @@ -413,6 +491,9 @@ 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,
> +       .del_reset_vq    = vp_modern_del_reset_vq,
> +       .enable_reset_vq = vp_modern_enable_reset_vq,
>  };
>
>  /* the PCI probing function */
> diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
> index 4d107ad31149..6e94f7d0e153 100644
> --- a/include/linux/virtio_config.h
> +++ b/include/linux/virtio_config.h
> @@ -74,6 +74,21 @@ struct virtio_shm_region {
>   * @set_vq_affinity: set the affinity for a virtqueue (optional).
>   * @get_vq_affinity: get the affinity for a virtqueue (optional).
>   * @get_shm_region: get a shared memory region based on the index.
> + * @reset_vq: reset a queue individually
> + *     vdev: the device
> + *     queue_index: the queue index
> + *     returns 0 on success or error status
> + * @del_reset_vq: del a reset queue
> + *     vdev: the device
> + *     queue_index: the queue index
> + *     returns 0 on success or error status.
> + * @enable_reset_vq: enable a reset queue
> + *     vdev: the device
> + *     queue_index: the queue index
> + *     callback: callback for the virtqueue, NULL for vq that do not need
a callback
> + *     name: virtqueue names (mainly for debugging), NULL for vq unused by
driver
> + *     ctx: ctx
> + *     returns vq on success or error status
>   */
>  typedef void vq_callback_t(struct virtqueue *);
>  struct virtio_config_ops {
> @@ -100,6 +115,12 @@ struct virtio_config_ops {
>                         int index);
>         bool (*get_shm_region)(struct virtio_device *vdev,
>                                struct virtio_shm_region *region, u8 id);
> +       int (*reset_vq)(struct virtio_device *vdev, u16 queue_index);
> +       int (*del_reset_vq)(struct virtio_device *vdev, u16 queue_index);
> +       struct virtqueue *(*enable_reset_vq)(struct virtio_device *vdev,
> +                                            u16 queue_index,
> +                                            vq_callback_t *callback,
> +                                            const char *name, const bool
*ctx);
>  };
>
>  /* If driver didn't advertise the feature, it will never appear. */
> --
> 2.31.0
>

Jason Wang

2022-Jan-19 06:12 UTC

head link

[PATCH 5/6] virtio: queue_reset: pci: support VIRTIO_F_RING_RESET

On Wed, Jan 19, 2022 at 2:11 PM Jason Wang <jasowang at redhat.com>
wrote:>
> On Wed, Jan 19, 2022 at 10:35 AM Xuan Zhuo <xuanzhuo at
linux.alibaba.com> wrote:
> >
> > This patch implements virtio pci support for QUEUE RESET.
> >
> > Performing reset on a queue is divided into three steps:
> >
> > 1. reset_vq: notify the hardware queue to reset
> > 2. del_reset_vq: delete the reset queue
> > 3. enable_reset_vq: re-enable the reset queue
> >
> > Between steps 1 and 2, generally call virtqueue_detach_unused_buf() to
> > recycle the buffer.
>
> I wonder if it's better to squash 1, 2 and
> virtqueue_detach_unused_buf() into a single helper.
>
> >
> > When deleting a vq, vp_del_vq() will be called to release all the
memory
> > of the vq. But this does not affect the process of deleting vqs,
because
> > that is based on the queue to release all the vqs. During this
process,
> > the vq has been removed from the queue.
> >
> > When deleting vq, info and vq will be released, and I save msix_vec in
> > vp_dev->vqs[queue_index]. When re-enable, the current msix_vec can
be
> > reused. And based on intx_enabled to determine which method to use to
> > enable this queue.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
> > ---
> >  drivers/virtio/virtio_pci_common.c | 54 ++++++++++++++++++++
> >  drivers/virtio/virtio_pci_common.h |  5 ++
> >  drivers/virtio/virtio_pci_modern.c | 81
++++++++++++++++++++++++++++++
> >  include/linux/virtio_config.h      | 21 ++++++++
> >  4 files changed, 161 insertions(+)
> >
> > diff --git a/drivers/virtio/virtio_pci_common.c
b/drivers/virtio/virtio_pci_common.c
> > index 5afe207ce28a..615a5a5f757c 100644
> > --- a/drivers/virtio/virtio_pci_common.c
> > +++ b/drivers/virtio/virtio_pci_common.c
> > @@ -464,6 +464,60 @@ int vp_find_vqs(struct virtio_device *vdev,
unsigned nvqs,
> >         return vp_find_vqs_intx(vdev, nvqs, vqs, callbacks, names,
ctx);
> >  }
> >
> > +#define VQ_IS_DELETED(vp_dev, idx) ((unsigned
long)vp_dev->vqs[idx] & 1)
> > +#define VQ_RESET_MSIX_VEC(vp_dev, idx) ((unsigned
long)vp_dev->vqs[idx] >> 2)
> > +#define VQ_RESET_MARK(msix_vec) ((void *)(long)((msix_vec << 2)
+ 1))
> > +
> > +int vp_del_reset_vq(struct virtio_device *vdev, u16 queue_index)
> > +{
> > +       struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > +       struct virtio_pci_vq_info *info;
> > +       u16 msix_vec;
> > +
> > +       if (VQ_IS_DELETED(vp_dev, queue_index))
> > +               return -EPERM;
> > +
> > +       info = vp_dev->vqs[queue_index];
> > +
> > +       msix_vec = info->msix_vector;
> > +
> > +       /* delete vq */
> > +       vp_del_vq(info->vq);
> > +
> > +       /* Mark the vq has been deleted, and save the msix_vec. */
> > +       vp_dev->vqs[queue_index] = VQ_RESET_MARK(msix_vec);
> > +
> > +       return 0;
> > +}
> > +
> > +struct virtqueue *vp_enable_reset_vq(struct virtio_device *vdev,
> > +                                    int queue_index,
> > +                                    vq_callback_t *callback,
> > +                                    const char *name,
> > +                                    const bool ctx)
> > +{
> > +       struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > +       struct virtqueue *vq;
> > +       u16 msix_vec;
> > +
> > +       if (!VQ_IS_DELETED(vp_dev, queue_index))
> > +               return ERR_PTR(-EPERM);
> > +
> > +       msix_vec = VQ_RESET_MSIX_VEC(vp_dev, queue_index);
> > +
> > +       if (vp_dev->intx_enabled)
> > +               vq = vp_setup_vq(vdev, queue_index, callback, name,
ctx,
> > +                                VIRTIO_MSI_NO_VECTOR);
> > +       else
> > +               vq = vp_enable_vq_msix(vdev, queue_index, callback,
name, ctx,
> > +                                      msix_vec);
> > +
> > +       if (IS_ERR(vq))
> > +               vp_dev->vqs[queue_index] = VQ_RESET_MARK(msix_vec);
> > +
> > +       return vq;
> > +}
> > +
> >  const char *vp_bus_name(struct virtio_device *vdev)
> >  {
> >         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > diff --git a/drivers/virtio/virtio_pci_common.h
b/drivers/virtio/virtio_pci_common.h
> > index 23f6c5c678d5..a92c99cc010e 100644
> > --- a/drivers/virtio/virtio_pci_common.h
> > +++ b/drivers/virtio/virtio_pci_common.h
> > @@ -115,6 +115,11 @@ int vp_find_vqs(struct virtio_device *vdev,
unsigned nvqs,
> >                 struct virtqueue *vqs[], vq_callback_t *callbacks[],
> >                 const char * const names[], const bool *ctx,
> >                 struct irq_affinity *desc);
> > +void vp_reset_vq(struct virtio_device *vdev, u16 queue_index);
> > +int vp_del_reset_vq(struct virtio_device *vdev, u16 queue_index);
> > +struct virtqueue *vp_enable_reset_vq(struct virtio_device *vdev, int
queue_index,
> > +                                    vq_callback_t *callback, const
char *name,
> > +                                    const bool ctx);
> >  const char *vp_bus_name(struct virtio_device *vdev);
> >
> >  /* Setup the affinity for a virtqueue:
> > diff --git a/drivers/virtio/virtio_pci_modern.c
b/drivers/virtio/virtio_pci_modern.c
> > index 5455bc041fb6..74e0b2b2f4dc 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 +179,78 @@ static void vp_reset(struct virtio_device *vdev)
> >         vp_disable_cbs(vdev);
> >  }
> >
> > +static int vp_modern_reset_vq(struct virtio_device *vdev, u16
queue_index)
> > +{
> > +       struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > +       struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
> > +       u16 msix_vec;
> > +
> > +       if (!virtio_has_feature(vdev, VIRTIO_F_RING_RESET))
> > +               return -ENOENT;
> > +
> > +       vp_modern_set_queue_reset(mdev, queue_index);
> > +
> > +       /* After write 1 to queue reset, the driver MUST wait for a
read of
> > +        * queue reset to return 1.
> > +        */
> > +       while (vp_modern_get_queue_reset(mdev, queue_index) != 1)
> > +               msleep(1);
> > +
> > +       msix_vec = vp_dev->vqs[queue_index]->msix_vector;
> > +
> > +       /* Disable VQ callback. */
> > +       if (vp_dev->per_vq_vectors && msix_vec !=
VIRTIO_MSI_NO_VECTOR)
> > +               disable_irq(pci_irq_vector(vp_dev->pci_dev,
msix_vec));
>
> What happens if the irq is shared among virtqueues?
>
> > +
> > +       return 0;
> > +}
> > +
> > +static int vp_modern_del_reset_vq(struct virtio_device *vdev, u16
queue_index)
> > +{
> > +       struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > +       struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
> > +
> > +       if (!virtio_has_feature(vdev, VIRTIO_F_RING_RESET))
> > +               return -ENOENT;
> > +
> > +       /* check queue reset status */
> > +       if (vp_modern_get_queue_reset(mdev, queue_index) != 1)
> > +               return -EBUSY;
> > +
> > +       return vp_del_reset_vq(vdev, queue_index);
> > +}
> > +
> > +static struct virtqueue *vp_modern_enable_reset_vq(struct
virtio_device *vdev,
> > +                                                  u16 queue_index,
> > +                                                  vq_callback_t
*callback,
> > +                                                  const char *name,
> > +                                                  const bool *ctx)
> > +{
> > +       struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > +       struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
> > +       struct virtqueue *vq;
> > +       u16 msix_vec;
> > +
> > +       if (!virtio_has_feature(vdev, VIRTIO_F_RING_RESET))
> > +               return ERR_PTR(-ENOENT);
> > +
> > +       /* check queue reset status */
> > +       if (vp_modern_get_queue_reset(mdev, queue_index) != 1)
> > +               return ERR_PTR(-EBUSY);
> > +
> > +       vq = vp_enable_reset_vq(vdev, queue_index, callback, name,
ctx);
> > +       if (IS_ERR(vq))
> > +               return vq;
> > +
> > +       vp_modern_set_queue_enable(&vp_dev->mdev, vq->index,
true);
> > +
> > +       msix_vec = vp_dev->vqs[queue_index]->msix_vector;
> > +       if (vp_dev->per_vq_vectors && msix_vec !=
VIRTIO_MSI_NO_VECTOR)
> > +               enable_irq(pci_irq_vector(vp_dev->pci_dev,
msix_vec));
> > +
> > +       return vq;
> > +}
> > +
> >  static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16
vector)
> >  {
> >         return vp_modern_config_vector(&vp_dev->mdev, vector);
> > @@ -395,6 +470,9 @@ 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,
> > +       .del_reset_vq    = vp_modern_del_reset_vq,
> > +       .enable_reset_vq = vp_modern_enable_reset_vq,
> >  };
> >
> >  static const struct virtio_config_ops virtio_pci_config_ops = {
> > @@ -413,6 +491,9 @@ 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,
> > +       .del_reset_vq    = vp_modern_del_reset_vq,
> > +       .enable_reset_vq = vp_modern_enable_reset_vq,
> >  };
> >
> >  /* the PCI probing function */
> > diff --git a/include/linux/virtio_config.h
b/include/linux/virtio_config.h
> > index 4d107ad31149..6e94f7d0e153 100644
> > --- a/include/linux/virtio_config.h
> > +++ b/include/linux/virtio_config.h
> > @@ -74,6 +74,21 @@ struct virtio_shm_region {
> >   * @set_vq_affinity: set the affinity for a virtqueue (optional).
> >   * @get_vq_affinity: get the affinity for a virtqueue (optional).
> >   * @get_shm_region: get a shared memory region based on the index.
> > + * @reset_vq: reset a queue individually
> > + *     vdev: the device
> > + *     queue_index: the queue index
> > + *     returns 0 on success or error status
> > + * @del_reset_vq: del a reset queue
> > + *     vdev: the device
> > + *     queue_index: the queue index
> > + *     returns 0 on success or error status.
> > + * @enable_reset_vq: enable a reset queue
> > + *     vdev: the device
> > + *     queue_index: the queue index
> > + *     callback: callback for the virtqueue, NULL for vq that do not
need a callback
> > + *     name: virtqueue names (mainly for debugging), NULL for vq
unused by driver
> > + *     ctx: ctx
> > + *     returns vq on success or error status
> >   */
> >  typedef void vq_callback_t(struct virtqueue *);
> >  struct virtio_config_ops {
> > @@ -100,6 +115,12 @@ struct virtio_config_ops {
> >                         int index);
> >         bool (*get_shm_region)(struct virtio_device *vdev,
> >                                struct virtio_shm_region *region, u8
id);
> > +       int (*reset_vq)(struct virtio_device *vdev, u16 queue_index);
> > +       int (*del_reset_vq)(struct virtio_device *vdev, u16
queue_index);
Btw, it's better to do this in a separate patch.

Thanks
> > +       struct virtqueue *(*enable_reset_vq)(struct virtio_device
*vdev,
> > +                                            u16 queue_index,
> > +                                            vq_callback_t *callback,
> > +                                            const char *name, const
bool *ctx);
> >  };
> >
> >  /* If driver didn't advertise the feature, it will never appear.
*/
> > --
> > 2.31.0
> >

Xuan Zhuo

2022-Jan-19 06:36 UTC

head link

[PATCH 5/6] virtio: queue_reset: pci: support VIRTIO_F_RING_RESET

On Wed, 19 Jan 2022 14:11:29 +0800, Jason Wang <jasowang at redhat.com>
wrote:> On Wed, Jan 19, 2022 at 10:35 AM Xuan Zhuo <xuanzhuo at
linux.alibaba.com> wrote:
> >
> > This patch implements virtio pci support for QUEUE RESET.
> >
> > Performing reset on a queue is divided into three steps:
> >
> > 1. reset_vq: notify the hardware queue to reset
> > 2. del_reset_vq: delete the reset queue
> > 3. enable_reset_vq: re-enable the reset queue
> >
> > Between steps 1 and 2, generally call virtqueue_detach_unused_buf() to
> > recycle the buffer.
>
> I wonder if it's better to squash 1, 2 and
> virtqueue_detach_unused_buf() into a single helper.
Oh, that's a good note. The only trouble is that the caller has to provide a
callback to handle the reclaimed buffer.

Thanks.
>
> >
> > When deleting a vq, vp_del_vq() will be called to release all the
memory
> > of the vq. But this does not affect the process of deleting vqs,
because
> > that is based on the queue to release all the vqs. During this
process,
> > the vq has been removed from the queue.
> >
> > When deleting vq, info and vq will be released, and I save msix_vec in
> > vp_dev->vqs[queue_index]. When re-enable, the current msix_vec can
be
> > reused. And based on intx_enabled to determine which method to use to
> > enable this queue.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
> > ---
> >  drivers/virtio/virtio_pci_common.c | 54 ++++++++++++++++++++
> >  drivers/virtio/virtio_pci_common.h |  5 ++
> >  drivers/virtio/virtio_pci_modern.c | 81
++++++++++++++++++++++++++++++
> >  include/linux/virtio_config.h      | 21 ++++++++
> >  4 files changed, 161 insertions(+)
> >
> > diff --git a/drivers/virtio/virtio_pci_common.c
b/drivers/virtio/virtio_pci_common.c
> > index 5afe207ce28a..615a5a5f757c 100644
> > --- a/drivers/virtio/virtio_pci_common.c
> > +++ b/drivers/virtio/virtio_pci_common.c
> > @@ -464,6 +464,60 @@ int vp_find_vqs(struct virtio_device *vdev,
unsigned nvqs,
> >         return vp_find_vqs_intx(vdev, nvqs, vqs, callbacks, names,
ctx);
> >  }
> >
> > +#define VQ_IS_DELETED(vp_dev, idx) ((unsigned
long)vp_dev->vqs[idx] & 1)
> > +#define VQ_RESET_MSIX_VEC(vp_dev, idx) ((unsigned
long)vp_dev->vqs[idx] >> 2)
> > +#define VQ_RESET_MARK(msix_vec) ((void *)(long)((msix_vec << 2)
+ 1))
> > +
> > +int vp_del_reset_vq(struct virtio_device *vdev, u16 queue_index)
> > +{
> > +       struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > +       struct virtio_pci_vq_info *info;
> > +       u16 msix_vec;
> > +
> > +       if (VQ_IS_DELETED(vp_dev, queue_index))
> > +               return -EPERM;
> > +
> > +       info = vp_dev->vqs[queue_index];
> > +
> > +       msix_vec = info->msix_vector;
> > +
> > +       /* delete vq */
> > +       vp_del_vq(info->vq);
> > +
> > +       /* Mark the vq has been deleted, and save the msix_vec. */
> > +       vp_dev->vqs[queue_index] = VQ_RESET_MARK(msix_vec);
> > +
> > +       return 0;
> > +}
> > +
> > +struct virtqueue *vp_enable_reset_vq(struct virtio_device *vdev,
> > +                                    int queue_index,
> > +                                    vq_callback_t *callback,
> > +                                    const char *name,
> > +                                    const bool ctx)
> > +{
> > +       struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > +       struct virtqueue *vq;
> > +       u16 msix_vec;
> > +
> > +       if (!VQ_IS_DELETED(vp_dev, queue_index))
> > +               return ERR_PTR(-EPERM);
> > +
> > +       msix_vec = VQ_RESET_MSIX_VEC(vp_dev, queue_index);
> > +
> > +       if (vp_dev->intx_enabled)
> > +               vq = vp_setup_vq(vdev, queue_index, callback, name,
ctx,
> > +                                VIRTIO_MSI_NO_VECTOR);
> > +       else
> > +               vq = vp_enable_vq_msix(vdev, queue_index, callback,
name, ctx,
> > +                                      msix_vec);
> > +
> > +       if (IS_ERR(vq))
> > +               vp_dev->vqs[queue_index] = VQ_RESET_MARK(msix_vec);
> > +
> > +       return vq;
> > +}
> > +
> >  const char *vp_bus_name(struct virtio_device *vdev)
> >  {
> >         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > diff --git a/drivers/virtio/virtio_pci_common.h
b/drivers/virtio/virtio_pci_common.h
> > index 23f6c5c678d5..a92c99cc010e 100644
> > --- a/drivers/virtio/virtio_pci_common.h
> > +++ b/drivers/virtio/virtio_pci_common.h
> > @@ -115,6 +115,11 @@ int vp_find_vqs(struct virtio_device *vdev,
unsigned nvqs,
> >                 struct virtqueue *vqs[], vq_callback_t *callbacks[],
> >                 const char * const names[], const bool *ctx,
> >                 struct irq_affinity *desc);
> > +void vp_reset_vq(struct virtio_device *vdev, u16 queue_index);
> > +int vp_del_reset_vq(struct virtio_device *vdev, u16 queue_index);
> > +struct virtqueue *vp_enable_reset_vq(struct virtio_device *vdev, int
queue_index,
> > +                                    vq_callback_t *callback, const
char *name,
> > +                                    const bool ctx);
> >  const char *vp_bus_name(struct virtio_device *vdev);
> >
> >  /* Setup the affinity for a virtqueue:
> > diff --git a/drivers/virtio/virtio_pci_modern.c
b/drivers/virtio/virtio_pci_modern.c
> > index 5455bc041fb6..74e0b2b2f4dc 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 +179,78 @@ static void vp_reset(struct virtio_device *vdev)
> >         vp_disable_cbs(vdev);
> >  }
> >
> > +static int vp_modern_reset_vq(struct virtio_device *vdev, u16
queue_index)
> > +{
> > +       struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > +       struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
> > +       u16 msix_vec;
> > +
> > +       if (!virtio_has_feature(vdev, VIRTIO_F_RING_RESET))
> > +               return -ENOENT;
> > +
> > +       vp_modern_set_queue_reset(mdev, queue_index);
> > +
> > +       /* After write 1 to queue reset, the driver MUST wait for a
read of
> > +        * queue reset to return 1.
> > +        */
> > +       while (vp_modern_get_queue_reset(mdev, queue_index) != 1)
> > +               msleep(1);
> > +
> > +       msix_vec = vp_dev->vqs[queue_index]->msix_vector;
> > +
> > +       /* Disable VQ callback. */
> > +       if (vp_dev->per_vq_vectors && msix_vec !=
VIRTIO_MSI_NO_VECTOR)
> > +               disable_irq(pci_irq_vector(vp_dev->pci_dev,
msix_vec));
>
> What happens if the irq is shared among virtqueues?
>
> > +
> > +       return 0;
> > +}
> > +
> > +static int vp_modern_del_reset_vq(struct virtio_device *vdev, u16
queue_index)
> > +{
> > +       struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > +       struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
> > +
> > +       if (!virtio_has_feature(vdev, VIRTIO_F_RING_RESET))
> > +               return -ENOENT;
> > +
> > +       /* check queue reset status */
> > +       if (vp_modern_get_queue_reset(mdev, queue_index) != 1)
> > +               return -EBUSY;
> > +
> > +       return vp_del_reset_vq(vdev, queue_index);
> > +}
> > +
> > +static struct virtqueue *vp_modern_enable_reset_vq(struct
virtio_device *vdev,
> > +                                                  u16 queue_index,
> > +                                                  vq_callback_t
*callback,
> > +                                                  const char *name,
> > +                                                  const bool *ctx)
> > +{
> > +       struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > +       struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
> > +       struct virtqueue *vq;
> > +       u16 msix_vec;
> > +
> > +       if (!virtio_has_feature(vdev, VIRTIO_F_RING_RESET))
> > +               return ERR_PTR(-ENOENT);
> > +
> > +       /* check queue reset status */
> > +       if (vp_modern_get_queue_reset(mdev, queue_index) != 1)
> > +               return ERR_PTR(-EBUSY);
> > +
> > +       vq = vp_enable_reset_vq(vdev, queue_index, callback, name,
ctx);
> > +       if (IS_ERR(vq))
> > +               return vq;
> > +
> > +       vp_modern_set_queue_enable(&vp_dev->mdev, vq->index,
true);
> > +
> > +       msix_vec = vp_dev->vqs[queue_index]->msix_vector;
> > +       if (vp_dev->per_vq_vectors && msix_vec !=
VIRTIO_MSI_NO_VECTOR)
> > +               enable_irq(pci_irq_vector(vp_dev->pci_dev,
msix_vec));
> > +
> > +       return vq;
> > +}
> > +
> >  static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16
vector)
> >  {
> >         return vp_modern_config_vector(&vp_dev->mdev, vector);
> > @@ -395,6 +470,9 @@ 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,
> > +       .del_reset_vq    = vp_modern_del_reset_vq,
> > +       .enable_reset_vq = vp_modern_enable_reset_vq,
> >  };
> >
> >  static const struct virtio_config_ops virtio_pci_config_ops = {
> > @@ -413,6 +491,9 @@ 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,
> > +       .del_reset_vq    = vp_modern_del_reset_vq,
> > +       .enable_reset_vq = vp_modern_enable_reset_vq,
> >  };
> >
> >  /* the PCI probing function */
> > diff --git a/include/linux/virtio_config.h
b/include/linux/virtio_config.h
> > index 4d107ad31149..6e94f7d0e153 100644
> > --- a/include/linux/virtio_config.h
> > +++ b/include/linux/virtio_config.h
> > @@ -74,6 +74,21 @@ struct virtio_shm_region {
> >   * @set_vq_affinity: set the affinity for a virtqueue (optional).
> >   * @get_vq_affinity: get the affinity for a virtqueue (optional).
> >   * @get_shm_region: get a shared memory region based on the index.
> > + * @reset_vq: reset a queue individually
> > + *     vdev: the device
> > + *     queue_index: the queue index
> > + *     returns 0 on success or error status
> > + * @del_reset_vq: del a reset queue
> > + *     vdev: the device
> > + *     queue_index: the queue index
> > + *     returns 0 on success or error status.
> > + * @enable_reset_vq: enable a reset queue
> > + *     vdev: the device
> > + *     queue_index: the queue index
> > + *     callback: callback for the virtqueue, NULL for vq that do not
need a callback
> > + *     name: virtqueue names (mainly for debugging), NULL for vq
unused by driver
> > + *     ctx: ctx
> > + *     returns vq on success or error status
> >   */
> >  typedef void vq_callback_t(struct virtqueue *);
> >  struct virtio_config_ops {
> > @@ -100,6 +115,12 @@ struct virtio_config_ops {
> >                         int index);
> >         bool (*get_shm_region)(struct virtio_device *vdev,
> >                                struct virtio_shm_region *region, u8
id);
> > +       int (*reset_vq)(struct virtio_device *vdev, u16 queue_index);
> > +       int (*del_reset_vq)(struct virtio_device *vdev, u16
queue_index);
> > +       struct virtqueue *(*enable_reset_vq)(struct virtio_device
*vdev,
> > +                                            u16 queue_index,
> > +                                            vq_callback_t *callback,
> > +                                            const char *name, const
bool *ctx);
> >  };
> >
> >  /* If driver didn't advertise the feature, it will never appear.
*/
> > --
> > 2.31.0
> >
>

Virtualization - Jan 2022 - [PATCH 5/6] virtio: queue_reset: pci: support VIRTIO_F_RING_RESET

[PATCH 5/6] virtio: queue_reset: pci: support VIRTIO_F_RING_RESET

[PATCH 5/6] virtio: queue_reset: pci: support VIRTIO_F_RING_RESET

[PATCH 5/6] virtio: queue_reset: pci: support VIRTIO_F_RING_RESET