On 12/14/18 4:59 PM, Jens Freimann wrote:
Add helper functions to set/clear and check descriptor flags.
Signed-off-by: Jens Freimann <jfreim...@redhat.com>
---
drivers/net/virtio/virtio_pci.h | 6 +++
drivers/net/virtio/virtqueue.h | 91 ++++++++++++++++++++++++++++++++-
2 files changed, 95 insertions(+), 2 deletions(-)
diff --git a/drivers/net/virtio/virtio_pci.h b/drivers/net/virtio/virtio_pci.h
index 4c975a531..b22b62dad 100644
--- a/drivers/net/virtio/virtio_pci.h
+++ b/drivers/net/virtio/virtio_pci.h
@@ -315,6 +315,12 @@ vtpci_with_feature(struct virtio_hw *hw, uint64_t bit)
return (hw->guest_features & (1ULL << bit)) != 0;
}
+static inline int
+vtpci_packed_queue(struct virtio_hw *hw)
+{
+ return vtpci_with_feature(hw, VIRTIO_F_RING_PACKED);
+}
+
/*
* Function declaration from virtio_pci.c
*/
diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
index d4e0858e4..19fabae0b 100644
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -251,6 +251,44 @@ struct virtio_tx_region {
__attribute__((__aligned__(16)));
};
+static inline void
+_set_desc_avail(struct vring_packed_desc *desc, int wrap_counter)
+{
+ desc->flags |= VRING_DESC_F_AVAIL(wrap_counter) |
+ VRING_DESC_F_USED(!wrap_counter);
+}
+
+static inline void
+set_desc_avail(struct virtqueue *vq, struct vring_packed_desc *desc)
+{
+ _set_desc_avail(desc, vq->avail_wrap_counter);
+}
+
+static inline int
+desc_is_used(struct vring_packed_desc *desc, struct virtqueue *vq)
+{
+ uint16_t used, avail, flags;
+
+ flags = desc->flags;
+ used = !!(flags & VRING_DESC_F_USED(1));
+ avail = !!(flags & VRING_DESC_F_AVAIL(1));
+
+ return avail == used && used == vq->used_wrap_counter;
+}
+
+
+static inline void
+vring_desc_init_packed(struct virtqueue *vq, int n)
+{
+ int i;
+ for (i = 0; i < n - 1; i++) {
+ vq->ring_packed.desc_packed[i].id = i;
+ vq->vq_descx[i].next = i + 1;
+ }
+ vq->ring_packed.desc_packed[i].id = i;
+ vq->vq_descx[i].next = VQ_RING_DESC_CHAIN_END;
+}
+
/* Chain all the descriptors in the ring with an END */
static inline void
vring_desc_init(struct vring_desc *dp, uint16_t n)
@@ -262,13 +300,59 @@ vring_desc_init(struct vring_desc *dp, uint16_t n)
dp[i].next = VQ_RING_DESC_CHAIN_END;
}
+/**
+ * Tell the backend not to interrupt us.
+ */
+static inline void
+virtqueue_disable_intr_packed(struct virtqueue *vq)
+{
+ uint16_t *event_flags = &vq->ring_packed.driver_event->desc_event_flags;
+
+ if (*event_flags != RING_EVENT_FLAGS_DISABLE)
+ *event_flags = RING_EVENT_FLAGS_DISABLE;
Why not just setting the value unconditionally?
IIUC, it is not called in the hot path?
+}
+
+
/**
* Tell the backend not to interrupt us.
*/
static inline void
virtqueue_disable_intr(struct virtqueue *vq)
{
- vq->vq_ring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
+ if (vtpci_packed_queue(vq->hw))
+ virtqueue_disable_intr_packed(vq);
+ else
+ vq->vq_ring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
+}
+
+/**
+ * Tell the backend to interrupt. Implementation for packed virtqueues.
+ */
+static inline void
+virtqueue_enable_intr_packed(struct virtqueue *vq)
+{
+ uint16_t *off_wrap = &vq->ring_packed.driver_event->desc_event_off_wrap;
+ uint16_t *event_flags = &vq->ring_packed.driver_event->desc_event_flags;
+
+ *off_wrap = vq->vq_used_cons_idx |
+ ((uint16_t)(vq->used_wrap_counter << 15));
Don't we want to set off_wrap only if VIRTIO_RING_F_EVENT_IDX
negotiated?
+
+ if (vq->event_flags_shadow == RING_EVENT_FLAGS_DISABLE) {
+ virtio_wmb();
+ vq->event_flags_shadow =
+ vtpci_with_feature(vq->hw, VIRTIO_RING_F_EVENT_IDX) ?
+ RING_EVENT_FLAGS_DESC : RING_EVENT_FLAGS_ENABLE;
+ *event_flags = vq->event_flags_shadow;
+ }
+}
+
+/**
+ * Tell the backend to interrupt. Implementation for split virtqueues.
+ */
+static inline void
+virtqueue_enable_intr_split(struct virtqueue *vq)
+{
+ vq->vq_ring.avail->flags &= (~VRING_AVAIL_F_NO_INTERRUPT);
}
/**
@@ -277,7 +361,10 @@ virtqueue_disable_intr(struct virtqueue *vq)
static inline void
virtqueue_enable_intr(struct virtqueue *vq)
{
- vq->vq_ring.avail->flags &= (~VRING_AVAIL_F_NO_INTERRUPT);
+ if (vtpci_packed_queue(vq->hw))
+ virtqueue_enable_intr_packed(vq);
+ else
+ virtqueue_enable_intr_split(vq);
}
/**
