virtio: add VIRTIO_F_NOTIFICATION_DATA feature support

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>
Message-Id: <20230413081855.36643-2-alvaro.karsz@solid-run.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index 954fc31..0292276 100644 (file)
--- 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 3ff746e..dd4424c 100644 (file)
--- 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 6e71390..d6bb68b 100644 (file)
--- 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);
 
@@ -316,7 +331,7 @@ 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 34e3849..c5310ea 100644 (file)
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2762,6 +2762,23 @@ 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)
 {
@@ -2781,6 +2798,8 @@ 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 8b95b69..2550c91 100644 (file)
--- 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 3c05162..2c712c6 100644 (file)
--- a/include/uapi/linux/virtio_config.h
+++ b/include/uapi/linux/virtio_config.h
@@ -100,6 +100,12 @@
 #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.
  */
 #define VIRTIO_F_RING_RESET            40