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Message-ID: <1680141014.3084862-1-xuanzhuo@linux.alibaba.com>
Subject: Re: [PATCH v6] virtio: add VIRTIO_F_NOTIFICATION_DATA feature support
Date:   Thu, 30 Mar 2023 09:50:14 +0800
From:   Xuan Zhuo <xuanzhuo@linux.alibaba.com>
To:     Viktor Prutyanov <viktor@daynix.com>
Cc:     cohuck@redhat.com, pasic@linux.ibm.com, farman@linux.ibm.com,
        linux-s390@vger.kernel.org, kvm@vger.kernel.org,
        virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org, yan@daynix.com, mst@redhat.com,
        jasowang@redhat.com
References: <20230324195029.2410503-1-viktor@daynix.com>
 <CAPv0NP7e95ZYk1-XdQitGwiqRNUQFx=a_2s7ivD4y-PzGRdhsw@mail.gmail.com>
In-Reply-To: <CAPv0NP7e95ZYk1-XdQitGwiqRNUQFx=a_2s7ivD4y-PzGRdhsw@mail.gmail.com>
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On Thu, 30 Mar 2023 01:49:23 +0300, Viktor Prutyanov <viktor@daynix.com> wr=
ote:
> On Fri, Mar 24, 2023 at 10:50=E2=80=AFPM Viktor Prutyanov <viktor@daynix.=
com> wrote:
> >
> > According to VirtIO spec v1.2, VIRTIO_F_NOTIFICATION_DATA feature
> > indicates that the driver passes extra data along with the queue
> > notifications.
> >
> > In a split queue case, the extra data is 16-bit available index. In a
> > packed queue case, the extra data is 1-bit wrap counter and 15-bit
> > available index.
> >
> > Add support for this feature for MMIO, channel I/O and modern PCI
> > transports.
> >
> > Signed-off-by: Viktor Prutyanov <viktor@daynix.com>
> > Acked-by: Jason Wang <jasowang@redhat.com>
> > Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > ---
> >  v6: use VRING_PACKED_EVENT_F_WRAP_CTR
> >  v5: replace ternary operator with if-else
> >  v4: remove VP_NOTIFY macro and legacy PCI support, add
> >     virtio_ccw_kvm_notify_with_data to virtio_ccw
> >  v3: support feature in virtio_ccw, remove VM_NOTIFY, use avail_idx_sha=
dow,
> >     remove byte swap, rename to vring_notification_data
> >  v2: reject the feature in virtio_ccw, replace __le32 with u32
> >
> >  Tested with disabled VIRTIO_F_NOTIFICATION_DATA on qemu-system-s390x
> >  (virtio-blk-ccw), qemu-system-riscv64 (virtio-blk-device,
> >  virtio-rng-device), qemu-system-x86_64 (virtio-blk-pci, virtio-net-pci)
> >  to make sure nothing is broken.
> >  Tested with enabled VIRTIO_F_NOTIFICATION_DATA on 64-bit RISC-V Linux
> >  and my hardware implementation of virtio-rng with MMIO.
> >
> >  drivers/s390/virtio/virtio_ccw.c   | 22 +++++++++++++++++++---
> >  drivers/virtio/virtio_mmio.c       | 18 +++++++++++++++++-
> >  drivers/virtio/virtio_pci_modern.c | 17 ++++++++++++++++-
> >  drivers/virtio/virtio_ring.c       | 19 +++++++++++++++++++
> >  include/linux/virtio_ring.h        |  2 ++
> >  include/uapi/linux/virtio_config.h |  6 ++++++
> >  6 files changed, 79 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/vir=
tio_ccw.c
> > index 954fc31b4bc7..02922768b129 100644
> > --- a/drivers/s390/virtio/virtio_ccw.c
> > +++ b/drivers/s390/virtio/virtio_ccw.c
> > @@ -391,7 +391,7 @@ static void virtio_ccw_drop_indicator(struct virtio=
_ccw_device *vcdev,
> >         ccw_device_dma_free(vcdev->cdev, thinint_area, sizeof(*thinint_=
area));
> >  }
> >
> > -static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> > +static inline bool virtio_ccw_do_kvm_notify(struct virtqueue *vq, u32 =
data)
> >  {
> >         struct virtio_ccw_vq_info *info =3D vq->priv;
> >         struct virtio_ccw_device *vcdev;
> > @@ -402,12 +402,22 @@ static bool virtio_ccw_kvm_notify(struct virtqueu=
e *vq)
> >         BUILD_BUG_ON(sizeof(struct subchannel_id) !=3D sizeof(unsigned =
int));
> >         info->cookie =3D kvm_hypercall3(KVM_S390_VIRTIO_CCW_NOTIFY,
> >                                       *((unsigned int *)&schid),
> > -                                     vq->index, info->cookie);
> > +                                     data, info->cookie);
> >         if (info->cookie < 0)
> >                 return false;
> >         return true;
> >  }
> >
> > +static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> > +{
> > +       return virtio_ccw_do_kvm_notify(vq, vq->index);
> > +}
> > +
> > +static bool virtio_ccw_kvm_notify_with_data(struct virtqueue *vq)
> > +{
> > +       return virtio_ccw_do_kvm_notify(vq, vring_notification_data(vq)=
);
> > +}
> > +
> >  static int virtio_ccw_read_vq_conf(struct virtio_ccw_device *vcdev,
> >                                    struct ccw1 *ccw, int index)
> >  {
> > @@ -495,6 +505,7 @@ static struct virtqueue *virtio_ccw_setup_vq(struct=
 virtio_device *vdev,
> >                                              struct ccw1 *ccw)
> >  {
> >         struct virtio_ccw_device *vcdev =3D to_vc_device(vdev);
> > +       bool (*notify)(struct virtqueue *vq);
> >         int err;
> >         struct virtqueue *vq =3D NULL;
> >         struct virtio_ccw_vq_info *info;
> > @@ -502,6 +513,11 @@ static struct virtqueue *virtio_ccw_setup_vq(struc=
t virtio_device *vdev,
> >         unsigned long flags;
> >         bool may_reduce;
> >
> > +       if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA))
> > +               notify =3D virtio_ccw_kvm_notify_with_data;
> > +       else
> > +               notify =3D virtio_ccw_kvm_notify;
> > +
> >         /* Allocate queue. */
> >         info =3D kzalloc(sizeof(struct virtio_ccw_vq_info), GFP_KERNEL);
> >         if (!info) {
> > @@ -524,7 +540,7 @@ static struct virtqueue *virtio_ccw_setup_vq(struct=
 virtio_device *vdev,
> >         may_reduce =3D vcdev->revision > 0;
> >         vq =3D vring_create_virtqueue(i, info->num, KVM_VIRTIO_CCW_RING=
_ALIGN,
> >                                     vdev, true, may_reduce, ctx,
> > -                                   virtio_ccw_kvm_notify, callback, na=
me);
> > +                                   notify, callback, name);
> >
> >         if (!vq) {
> >                 /* For now, we fail if we can't get the requested size.=
 */
> > diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> > index 3ff746e3f24a..dd4424c14233 100644
> > --- a/drivers/virtio/virtio_mmio.c
> > +++ b/drivers/virtio/virtio_mmio.c
> > @@ -285,6 +285,16 @@ static bool vm_notify(struct virtqueue *vq)
> >         return true;
> >  }
> >
> > +static bool vm_notify_with_data(struct virtqueue *vq)
> > +{
> > +       struct virtio_mmio_device *vm_dev =3D to_virtio_mmio_device(vq-=
>vdev);
> > +       u32 data =3D vring_notification_data(vq);
> > +
> > +       writel(data, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
> > +
> > +       return true;
> > +}
> > +
> >  /* Notify all virtqueues on an interrupt. */
> >  static irqreturn_t vm_interrupt(int irq, void *opaque)
> >  {
> > @@ -363,12 +373,18 @@ static struct virtqueue *vm_setup_vq(struct virti=
o_device *vdev, unsigned int in
> >                                   const char *name, bool ctx)
> >  {
> >         struct virtio_mmio_device *vm_dev =3D to_virtio_mmio_device(vde=
v);
> > +       bool (*notify)(struct virtqueue *vq);
> >         struct virtio_mmio_vq_info *info;
> >         struct virtqueue *vq;
> >         unsigned long flags;
> >         unsigned int num;
> >         int err;
> >
> > +       if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA))
> > +               notify =3D vm_notify_with_data;
> > +       else
> > +               notify =3D vm_notify;
> > +
> >         if (!name)
> >                 return NULL;
> >
> > @@ -397,7 +413,7 @@ static struct virtqueue *vm_setup_vq(struct virtio_=
device *vdev, unsigned int in
> >
> >         /* Create the vring */
> >         vq =3D vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALI=
GN, vdev,
> > -                                true, true, ctx, vm_notify, callback, =
name);
> > +                                true, true, ctx, notify, callback, nam=
e);
> >         if (!vq) {
> >                 err =3D -ENOMEM;
> >                 goto error_new_virtqueue;
> > diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio=
_pci_modern.c
> > index 9e496e288cfa..05deba5153bd 100644
> > --- a/drivers/virtio/virtio_pci_modern.c
> > +++ b/drivers/virtio/virtio_pci_modern.c
> > @@ -288,6 +288,15 @@ static u16 vp_config_vector(struct virtio_pci_devi=
ce *vp_dev, u16 vector)
> >         return vp_modern_config_vector(&vp_dev->mdev, vector);
> >  }
> >
> > +static bool vp_notify_with_data(struct virtqueue *vq)
> > +{
> > +       u32 data =3D vring_notification_data(vq);
> > +
> > +       iowrite32(data, (void __iomem *)vq->priv);
> > +
> > +       return true;
> > +}
> > +
> >  static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> >                                   struct virtio_pci_vq_info *info,
> >                                   unsigned int index,
> > @@ -298,10 +307,16 @@ static struct virtqueue *setup_vq(struct virtio_p=
ci_device *vp_dev,
> >  {
> >
> >         struct virtio_pci_modern_device *mdev =3D &vp_dev->mdev;
> > +       bool (*notify)(struct virtqueue *vq);
> >         struct virtqueue *vq;
> >         u16 num;
> >         int err;
> >
> > +       if (__virtio_test_bit(&vp_dev->vdev, VIRTIO_F_NOTIFICATION_DATA=
))
> > +               notify =3D vp_notify_with_data;
> > +       else
> > +               notify =3D vp_notify;
> > +
> >         if (index >=3D vp_modern_get_num_queues(mdev))
> >                 return ERR_PTR(-EINVAL);
> >
> > @@ -321,7 +336,7 @@ static struct virtqueue *setup_vq(struct virtio_pci=
_device *vp_dev,
> >         vq =3D vring_create_virtqueue(index, num,
> >                                     SMP_CACHE_BYTES, &vp_dev->vdev,
> >                                     true, true, ctx,
> > -                                   vp_notify, callback, name);
> > +                                   notify, callback, name);
> >         if (!vq)
> >                 return ERR_PTR(-ENOMEM);
> >
> > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > index 4c3bb0ddeb9b..f9c6604352b4 100644
> > --- a/drivers/virtio/virtio_ring.c
> > +++ b/drivers/virtio/virtio_ring.c
> > @@ -2752,6 +2752,23 @@ void vring_del_virtqueue(struct virtqueue *_vq)
> >  }
> >  EXPORT_SYMBOL_GPL(vring_del_virtqueue);
> >
> > +u32 vring_notification_data(struct virtqueue *_vq)
> > +{
> > +       struct vring_virtqueue *vq =3D to_vvq(_vq);
> > +       u16 next;
> > +
> > +       if (vq->packed_ring)
> > +               next =3D (vq->packed.next_avail_idx &
> > +                               ~(-(1 << VRING_PACKED_EVENT_F_WRAP_CTR)=
)) |
> > +                       vq->packed.avail_wrap_counter <<
> > +                               VRING_PACKED_EVENT_F_WRAP_CTR;
> > +       else
> > +               next =3D vq->split.avail_idx_shadow;
> > +
> > +       return next << 16 | _vq->index;
> > +}
> > +EXPORT_SYMBOL_GPL(vring_notification_data);
> > +
> >  /* Manipulates transport-specific feature bits. */
> >  void vring_transport_features(struct virtio_device *vdev)
> >  {
> > @@ -2771,6 +2788,8 @@ void vring_transport_features(struct virtio_devic=
e *vdev)
> >                         break;
> >                 case VIRTIO_F_ORDER_PLATFORM:
> >                         break;
> > +               case VIRTIO_F_NOTIFICATION_DATA:
> > +                       break;
> >                 default:
> >                         /* We don't understand this bit. */
> >                         __virtio_clear_bit(vdev, i);
> > diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
> > index 8b95b69ef694..2550c9170f4f 100644
> > --- a/include/linux/virtio_ring.h
> > +++ b/include/linux/virtio_ring.h
> > @@ -117,4 +117,6 @@ void vring_del_virtqueue(struct virtqueue *vq);
> >  void vring_transport_features(struct virtio_device *vdev);
> >
> >  irqreturn_t vring_interrupt(int irq, void *_vq);
> > +
> > +u32 vring_notification_data(struct virtqueue *_vq);
> >  #endif /* _LINUX_VIRTIO_RING_H */
> > diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/vi=
rtio_config.h
> > index 3c05162bc988..2c712c654165 100644
> > --- a/include/uapi/linux/virtio_config.h
> > +++ b/include/uapi/linux/virtio_config.h
> > @@ -99,6 +99,12 @@
> >   */
> >  #define VIRTIO_F_SR_IOV                        37
> >
> > +/*
> > + * This feature indicates that the driver passes extra data (besides
> > + * identifying the virtqueue) in its device notifications.
> > + */
> > +#define VIRTIO_F_NOTIFICATION_DATA     38
> > +
> >  /*
> >   * This feature indicates that the driver can reset a queue individual=
ly.
> >   */
> > --
> > 2.35.1
> >
>
> ping

Generally speaking, Michael will merge patch here and will not reply in the=
 mail
list. You can see it here.

https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git/log/?h=3Dlinu=
x-next

At present, this patch has not been merged, and you need to give Micheal so=
me
time.

Thanks.