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mirror of https://git.FreeBSD.org/src.git synced 2024-12-22 11:17:19 +00:00
freebsd/sys/dev/virtio/virtio_ring.h
Peter Grehan 336f459c31 Catch up with Bryan Venteicher's virtio Hg repo:
c162516
  Remove vtblk_sector_size

c162515
  Wrap long license lines

c162514
  Remove vtblk_unit

c162513
  Wrap long lines in the license.

c162512
  Remove verbose messages when link goes up/down.

  A similar message is printed elsewhere as a result of
  if_link_state_change().

c162511
  Explicity compare pointer to NULL

c162510
  Allocate the mac filter table at attach time.

c162509
  Add real BSD licenses to the header files copied from Linux.

  The chases upstream changes made in Linux awhile ago.

c162508
  Only notify if we actually dequeued something.

c162507
  Change a couple of if () { KASSERT(...) } to just KASSERTs.

  In non-debug kernels, the if() { } probably get optomized
  away, but I guess this is clearer.

c162506
  Remove VIRTIO_BLK_F_TOPOLOGY fields in the config.

  TOPOLOGY has since been removed from the spec, and the FreeBSD
  didn't really do anything with the fields anyways.

c162505
  Move vtblk_enqueue_request() outside the locks when getting the ident.

c162504
  Remove soon to be uneeded trylock during dump [1].
  http://lists.freebsd.org/pipermail/freebsd-current/2011-November/029226.html

c162503
  Remove emtpy line

c162502
  Drop frame if cannot allocate a vtnet_tx_header.

  If we don't, we set OACTIVE, but if there are no
  other frames in flight, vtnet_txeof() will never
  be called to unset OACTIVE. The interface would
  have to be down/up'ed in order to become usable.

  We could be cuter here and only do this if the
  virtqueue is emtpy, but its probably not worth
  the complication.

c162501
  Start mbuf replacement loop at 1 for clarity

Obtained from:	Bryan Venteicher  bryanv at daemoninthecloset dot org
2011-12-06 06:28:32 +00:00

144 lines
4.7 KiB
C

/*-
* Copyright Rusty Russell IBM Corporation 2007.
*
* 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.
*
* $FreeBSD$
*/
#ifndef VIRTIO_RING_H
#define VIRTIO_RING_H
#include <sys/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
/* VirtIO ring descriptors: 16 bytes.
* These can chain together via "next". */
struct vring_desc {
/* Address (guest-physical). */
uint64_t addr;
/* Length. */
uint32_t len;
/* The flags as indicated above. */
uint16_t flags;
/* We chain unused descriptors via this, too. */
uint16_t next;
};
struct vring_avail {
uint16_t flags;
uint16_t idx;
uint16_t ring[0];
};
/* uint32_t is used here for ids for padding reasons. */
struct vring_used_elem {
/* Index of start of used descriptor chain. */
uint32_t id;
/* Total length of the descriptor chain which was written to. */
uint32_t len;
};
struct vring_used {
uint16_t flags;
uint16_t idx;
struct vring_used_elem ring[0];
};
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];
* };
*
* NOTE: for VirtIO PCI, align is 4096.
*/
static inline int
vring_size(unsigned int num, unsigned long align)
{
int size;
size = num * sizeof(struct vring_desc);
size += sizeof(struct vring_avail) + (num * sizeof(uint16_t));
size = (size + align - 1) & ~(align - 1);
size += sizeof(struct vring_used) +
(num * sizeof(struct vring_used_elem));
return (size);
}
static inline void
vring_init(struct vring *vr, unsigned int num, uint8_t *p,
unsigned long align)
{
vr->num = num;
vr->desc = (struct vring_desc *) p;
vr->avail = (struct vring_avail *) (p +
num * sizeof(struct vring_desc));
vr->used = (void *)
(((unsigned long) &vr->avail->ring[num] + align-1) & ~(align-1));
}
#endif /* VIRTIO_RING_H */