Michael S. Tsirkin
2023-Mar-24 09:07 UTC
[PATCH v5] virtio: add VIRTIO_F_NOTIFICATION_DATA feature support
On Fri, Mar 24, 2023 at 10:44:23AM +0300, Viktor Prutyanov wrote:> On Fri, Mar 24, 2023 at 8:31?AM Michael S. Tsirkin <mst at redhat.com> wrote: > > > > On Fri, Mar 24, 2023 at 11:09:19AM +0800, Jason Wang wrote: > > > On Thu, Mar 23, 2023 at 4:56?PM Viktor Prutyanov <viktor at 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 at daynix.com> > > > > --- > > > > 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 | 17 +++++++++++++++++ > > > > include/linux/virtio_ring.h | 2 ++ > > > > include/uapi/linux/virtio_config.h | 6 ++++++ > > > > 6 files changed, 77 insertions(+), 5 deletions(-) > > > > > > > > diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c > > > > index 954fc31b4bc7..9a9c5d34454c 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) > > > > { > > > > @@ -501,6 +511,12 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev, > > > > u64 queue; > > > > unsigned long flags; > > > > bool may_reduce; > > > > + bool (*notify)(struct virtqueue *vq); > > > > + > > > > + 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); > > > > @@ -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..7e87f745f68d 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) > > > > { > > > > @@ -368,6 +378,12 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in > > > > unsigned long flags; > > > > unsigned int num; > > > > int err; > > > > + bool (*notify)(struct virtqueue *vq); > > > > + > > > > + 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..3bfc368b279e 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, > > > > @@ -301,6 +310,12 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev, > > > > struct virtqueue *vq; > > > > u16 num; > > > > int err; > > > > + bool (*notify)(struct virtqueue *vq); > > > > + > > > > + 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..837875cc3190 100644 > > > > --- a/drivers/virtio/virtio_ring.c > > > > +++ b/drivers/virtio/virtio_ring.c > > > > @@ -2752,6 +2752,21 @@ 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 << 15)) | > > > > + vq->packed.avail_wrap_counter << 15; > > > > > > Nit: We have VRING_PACKED_EVENT_F_WRAP_CTR which could be used for > > > replacing 15 here. > > > > > > And we have many places for packing them into u16, it might be better > > > to introduce a helper. > > > > Not sure about a helper, I'd leave that for a future cleanup. > > > > However I would use > > > > & (-(1 << VRING_PACKED_EVENT_F_WRAP_CTR)) > > Do you mean > & (~(1 << VRING_PACKED_EVENT_F_WRAP_CTR)) > or maybe I missed something?Sorry. I meant: ~(-(1 << VRING_PACKED_EVENT_F_WRAP_CTR)) which means "all bits above VRING_PACKED_EVENT_F_WRAP_CTR".> > > > that's more robust - works for any value of VRING_PACKED_EVENT_F_WRAP_CTR > > giving low bits 0 to VRING_PACKED_EVENT_F_WRAP_CTR, > > and will keep working if someone copypasted it and changed > > counter to a value different from 15. > > > > > > > Acked-by: Jason Wang <jasowang at redhat.com> > > > > > > Thanks > > > > > > > + 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 +2786,8 @@ 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 > > > > > >