standard-headers/linux/virtio_ring.h

7  * This header is BSD licensed so anyone can use the definitions to implement
11  * modification, are permitted provided that the following conditions
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of IBM nor the names of its contributors
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 /* This marks a buffer as continuing via the next field. */
42 /* This means the buffer contains a list of buffer descriptors. */
52 /* The Host uses this in used->flags to advise the Guest: don't kick me when
56 /* The Guest uses this in avail->flags to advise the Host: don't interrupt me
81 /* The Guest publishes the used index for which it expects an interrupt
82  * at the end of the avail ring. Host should ignore the avail->flags field. */
83 /* The Host publishes the avail index for which it expects a kick
84  * at the end of the used ring. Guest should ignore the used->flags field. */
101  * @next: index of the next descriptor in the chain,
102  *        if the VRING_DESC_F_NEXT flag is set. We chain unused
122 	/* Total length of the descriptor chain which was used (written to) */
136  * The ring element addresses are passed between components with different
137  * alignments assumptions. Thus, we might need to decrease the compiler-selected
138  * alignment, and so must use a typedef to make sure the aligned attribute
143  * When used on a struct, or struct member, the aligned attribute can only
144  * increase the alignment; in order to decrease it, the packed attribute must
145  * be specified as well. When used as part of a typedef, the aligned attribute
146  * can both increase and decrease alignment, and specifying the packed
168 /* The standard layout for the ring is a continuous chunk of memory which looks
173  *	// The actual descriptors (16 bytes each)
182  *	// Padding to the next align boundary.
192 /* We publish the used event index at the end of the available ring, and vice
193  * versa. They are at the end for backwards compatibility. */
216 /* The following is used with USED_EVENT_IDX and AVAIL_EVENT_IDX */
217 /* Assuming a given event_idx value from the other side, if
244 	/* The flags depending on descriptor type. */