On Fri, Mar 24, 2023 at 10:50 PM Viktor Prutyanov <viktor@xxxxxxxxxx> 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@xxxxxxxxxx> > Acked-by: Jason Wang <jasowang@xxxxxxxxxx> > Reviewed-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> > --- > 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_shadow, > 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/virtio_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 = vq->priv; > struct virtio_ccw_device *vcdev; > @@ -402,12 +402,22 @@ static bool virtio_ccw_kvm_notify(struct virtqueue *vq) > BUILD_BUG_ON(sizeof(struct subchannel_id) != sizeof(unsigned int)); > info->cookie = 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 = to_vc_device(vdev); > + bool (*notify)(struct virtqueue *vq); > int err; > struct virtqueue *vq = NULL; > struct virtio_ccw_vq_info *info; > @@ -502,6 +513,11 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev, > unsigned long flags; > bool may_reduce; > > + if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA)) > + notify = virtio_ccw_kvm_notify_with_data; > + else > + notify = virtio_ccw_kvm_notify; > + > /* Allocate queue. */ > info = 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 = vcdev->revision > 0; > vq = vring_create_virtqueue(i, info->num, KVM_VIRTIO_CCW_RING_ALIGN, > vdev, true, may_reduce, ctx, > - virtio_ccw_kvm_notify, callback, name); > + 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 = to_virtio_mmio_device(vq->vdev); > + u32 data = 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 virtio_device *vdev, unsigned int in > const char *name, bool ctx) > { > struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); > + 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 = vm_notify_with_data; > + else > + notify = 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 = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev, > - true, true, ctx, vm_notify, callback, name); > + true, true, ctx, notify, callback, name); > if (!vq) { > err = -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_device *vp_dev, u16 vector) > return vp_modern_config_vector(&vp_dev->mdev, vector); > } > > +static bool vp_notify_with_data(struct virtqueue *vq) > +{ > + u32 data = 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_pci_device *vp_dev, > { > > struct virtio_pci_modern_device *mdev = &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 = vp_notify_with_data; > + else > + notify = vp_notify; > + > if (index >= 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 = 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 = to_vvq(_vq); > + u16 next; > + > + if (vq->packed_ring) > + next = (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 = 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_device *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/virtio_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 individually. > */ > -- > 2.35.1 > ping