diff options
Diffstat (limited to 'include/linux/virtio_ring.h')
| -rw-r--r-- | include/linux/virtio_ring.h | 163 |
1 files changed, 2 insertions, 161 deletions
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h index c2d793a06ad..63c6ea19951 100644 --- a/include/linux/virtio_ring.h +++ b/include/linux/virtio_ring.h @@ -1,167 +1,9 @@ #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. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. Neither the name of IBM nor the names of its contributors - * may be used to endorse or promote products derived from this software - * without specific prior written permission. - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - * - * 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 -/* This means the buffer contains a list of buffer descriptors. */ -#define VRING_DESC_F_INDIRECT 4 - -/* 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 - -/* We support indirect buffer descriptors */ -#define VIRTIO_RING_F_INDIRECT_DESC 28 - -/* The Guest publishes the used index for which it expects an interrupt - * at the end of the avail ring. Host should ignore the avail->flags field. */ -/* The Host publishes the avail index for which it expects a kick - * at the end of the used ring. Guest should ignore the used->flags field. */ -#define VIRTIO_RING_F_EVENT_IDX 29 - -/* 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]; - * __u16 used_event_idx; - * - * // 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]; - * __u16 avail_event_idx; - * }; - */ -/* We publish the used event index at the end of the available ring, and vice - * versa. They are at the end for backwards compatibility. */ -#define vring_used_event(vr) ((vr)->avail->ring[(vr)->num]) -#define vring_avail_event(vr) (*(__u16 *)&(vr)->used->ring[(vr)->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] + sizeof(__u16) - + align-1) & ~(align - 1)); -} - -static inline unsigned vring_size(unsigned int num, unsigned long align) -{ - return ((sizeof(struct vring_desc) * num + sizeof(__u16) * (3 + num) - + align - 1) & ~(align - 1)) - + sizeof(__u16) * 3 + sizeof(struct vring_used_elem) * num; -} - -/* The following is used with USED_EVENT_IDX and AVAIL_EVENT_IDX */ -/* Assuming a given event_idx value from the other size, if - * we have just incremented index from old to new_idx, - * should we trigger an event? */ -static inline int vring_need_event(__u16 event_idx, __u16 new_idx, __u16 old) -{ - /* Note: Xen has similar logic for notification hold-off - * in include/xen/interface/io/ring.h with req_event and req_prod - * corresponding to event_idx + 1 and new_idx respectively. - * Note also that req_event and req_prod in Xen start at 1, - * event indexes in virtio start at 0. */ - return (__u16)(new_idx - event_idx - 1) < (__u16)(new_idx - old); -} - -#ifdef __KERNEL__ #include <linux/irqreturn.h> +#include <uapi/linux/virtio_ring.h> + struct virtio_device; struct virtqueue; @@ -179,5 +21,4 @@ void vring_del_virtqueue(struct virtqueue *vq); void vring_transport_features(struct virtio_device *vdev); irqreturn_t vring_interrupt(int irq, void *_vq); -#endif /* __KERNEL__ */ #endif /* _LINUX_VIRTIO_RING_H */ |