check in the original version of dde linux26.

1 files changed, 129 insertions, 0 deletions

diff --git a/libdde_linux26/contrib/include/linux/virtio_ring.h b/libdde_linux26/contrib/include/linux/virtio_ring.h
new file mode 100644
index 00000000..71e03722
--- /dev/null
+++ b/libdde_linux26/contrib/include/linux/virtio_ring.h
@@ -0,0 +1,129 @@
+#ifndef _LINUX_VIRTIO_RING_H
+#define _LINUX_VIRTIO_RING_H
+/* An interface for efficient virtio implementation, currently for use by KVM
+ * and lguest, but hopefully others soon.  Do NOT change this since it will
+ * break existing servers and clients.
+ *
+ * This header is BSD licensed so anyone can use the definitions to implement
+ * compatible drivers/servers.
+ *
+ * Copyright Rusty Russell IBM Corporation 2007. */
+#include <linux/types.h>
+
+/* This marks a buffer as continuing via the next field. */
+#define VRING_DESC_F_NEXT	1
+/* This marks a buffer as write-only (otherwise read-only). */
+#define VRING_DESC_F_WRITE	2
+
+/* 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. */
+#define VRING_USED_F_NO_NOTIFY	1
+/* The Guest uses this in avail->flags to advise the Host: don't interrupt me
+ * when you consume a buffer.  It's unreliable, so it's simply an
+ * optimization.  */
+#define VRING_AVAIL_F_NO_INTERRUPT	1
+
+/* Virtio ring descriptors: 16 bytes.  These can chain together via "next". */
+struct vring_desc
+{
+	/* Address (guest-physical). */
+	__u64 addr;
+	/* Length. */
+	__u32 len;
+	/* The flags as indicated above. */
+	__u16 flags;
+	/* We chain unused descriptors via this, too */
+	__u16 next;
+};
+
+struct vring_avail
+{
+	__u16 flags;
+	__u16 idx;
+	__u16 ring[];
+};
+
+/* u32 is used here for ids for padding reasons. */
+struct vring_used_elem
+{
+	/* Index of start of used descriptor chain. */
+	__u32 id;
+	/* Total length of the descriptor chain which was used (written to) */
+	__u32 len;
+};
+
+struct vring_used
+{
+	__u16 flags;
+	__u16 idx;
+	struct vring_used_elem ring[];
+};
+
+struct vring {
+	unsigned int num;
+
+	struct vring_desc *desc;
+
+	struct vring_avail *avail;
+
+	struct vring_used *used;
+};
+
+/* The standard layout for the ring is a continuous chunk of memory which looks
+ * like this.  We assume num is a power of 2.
+ *
+ * struct vring
+ * {
+ *	// The actual descriptors (16 bytes each)
+ *	struct vring_desc desc[num];
+ *
+ *	// A ring of available descriptor heads with free-running index.
+ *	__u16 avail_flags;
+ *	__u16 avail_idx;
+ *	__u16 available[num];
+ *
+ *	// Padding to the next align boundary.
+ *	char pad[];
+ *
+ *	// A ring of used descriptor heads with free-running index.
+ *	__u16 used_flags;
+ *	__u16 used_idx;
+ *	struct vring_used_elem used[num];
+ * };
+ */
+static inline void vring_init(struct vring *vr, unsigned int num, void *p,
+			      unsigned long align)
+{
+	vr->num = num;
+	vr->desc = p;
+	vr->avail = p + num*sizeof(struct vring_desc);
+	vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + align-1)
+			    & ~(align - 1));
+}
+
+static inline unsigned vring_size(unsigned int num, unsigned long align)
+{
+	return ((sizeof(struct vring_desc) * num + sizeof(__u16) * (2 + num)
+		 + align - 1) & ~(align - 1))
+		+ sizeof(__u16) * 2 + sizeof(struct vring_used_elem) * num;
+}
+
+#ifdef __KERNEL__
+#include <linux/irqreturn.h>
+struct virtio_device;
+struct virtqueue;
+
+struct virtqueue *vring_new_virtqueue(unsigned int num,
+				      unsigned int vring_align,
+				      struct virtio_device *vdev,
+				      void *pages,
+				      void (*notify)(struct virtqueue *vq),
+				      void (*callback)(struct virtqueue *vq));
+void vring_del_virtqueue(struct virtqueue *vq);
+/* Filter out transport-specific feature bits. */
+void vring_transport_features(struct virtio_device *vdev);
+
+irqreturn_t vring_interrupt(int irq, void *_vq);
+#endif /* __KERNEL__ */
+#endif /* _LINUX_VIRTIO_RING_H */