[PATCH net-next v2 1/5] virtio: add packed ring definitions

From: Tiwei Bie
Date: Tue Jul 10 2018 - 22:27:41 EST


Signed-off-by: Tiwei Bie <tiwei.bie@xxxxxxxxx>
---
include/uapi/linux/virtio_config.h | 3 +++
include/uapi/linux/virtio_ring.h | 43 ++++++++++++++++++++++++++++++
2 files changed, 46 insertions(+)

diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h
index 449132c76b1c..1196e1c1d4f6 100644
--- a/include/uapi/linux/virtio_config.h
+++ b/include/uapi/linux/virtio_config.h
@@ -75,6 +75,9 @@
*/
#define VIRTIO_F_IOMMU_PLATFORM 33

+/* This feature indicates support for the packed virtqueue layout. */
+#define VIRTIO_F_RING_PACKED 34
+
/*
* Does the device support Single Root I/O Virtualization?
*/
diff --git a/include/uapi/linux/virtio_ring.h b/include/uapi/linux/virtio_ring.h
index 6d5d5faa989b..0254a2ba29cf 100644
--- a/include/uapi/linux/virtio_ring.h
+++ b/include/uapi/linux/virtio_ring.h
@@ -44,6 +44,10 @@
/* This means the buffer contains a list of buffer descriptors. */
#define VRING_DESC_F_INDIRECT 4

+/* Mark a descriptor as available or used. */
+#define VRING_DESC_F_AVAIL (1ul << 7)
+#define VRING_DESC_F_USED (1ul << 15)
+
/* The Host uses this in used->flags to advise the Guest: don't kick me when
* you add a buffer. It's unreliable, so it's simply an optimization. Guest
* will still kick if it's out of buffers. */
@@ -53,6 +57,17 @@
* optimization. */
#define VRING_AVAIL_F_NO_INTERRUPT 1

+/* Enable events. */
+#define VRING_EVENT_F_ENABLE 0x0
+/* Disable events. */
+#define VRING_EVENT_F_DISABLE 0x1
+/*
+ * Enable events for a specific descriptor
+ * (as specified by Descriptor Ring Change Event Offset/Wrap Counter).
+ * Only valid if VIRTIO_RING_F_EVENT_IDX has been negotiated.
+ */
+#define VRING_EVENT_F_DESC 0x2
+
/* We support indirect buffer descriptors */
#define VIRTIO_RING_F_INDIRECT_DESC 28

@@ -171,4 +186,32 @@ static inline int vring_need_event(__u16 event_idx, __u16 new_idx, __u16 old)
return (__u16)(new_idx - event_idx - 1) < (__u16)(new_idx - old);
}

+struct vring_packed_desc_event {
+ /* Descriptor Ring Change Event Offset/Wrap Counter. */
+ __virtio16 off_wrap;
+ /* Descriptor Ring Change Event Flags. */
+ __virtio16 flags;
+};
+
+struct vring_packed_desc {
+ /* Buffer Address. */
+ __virtio64 addr;
+ /* Buffer Length. */
+ __virtio32 len;
+ /* Buffer ID. */
+ __virtio16 id;
+ /* The flags depending on descriptor type. */
+ __virtio16 flags;
+};
+
+struct vring_packed {
+ unsigned int num;
+
+ struct vring_packed_desc *desc;
+
+ struct vring_packed_desc_event *driver;
+
+ struct vring_packed_desc_event *device;
+};
+
#endif /* _UAPI_LINUX_VIRTIO_RING_H */
--
2.18.0