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//
// virtio.h
//
// Interface to virtual I/O devices (virtio)
//
// Copyright (C) 2011 Michael Ringgaard. All rights reserved.
//
// 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 the project 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 THE COPYRIGHT OWNER 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.
//
#ifndef VIRTIO_H
#define VIRTIO_H
//
// PCI virtio I/O registers.
//
#define VIRTIO_PCI_HOST_FEATURES 0 // Features supported by the host
#define VIRTIO_PCI_GUEST_FEATURES 4 // Features activated by the guest
#define VIRTIO_PCI_QUEUE_PFN 8 // PFN for the currently selected queue
#define VIRTIO_PCI_QUEUE_SIZE 12 // Queue size for the currently selected queue
#define VIRTIO_PCI_QUEUE_SEL 14 // Queue selector
#define VIRTIO_PCI_QUEUE_NOTIFY 16 // Queue notifier
#define VIRTIO_PCI_STATUS 18 // Device status register
#define VIRTIO_PCI_ISR 19 // Interrupt status register
#define VIRTIO_PCI_CONFIG 20 // Configuration data block
//
// PCI virtio status register bits
//
#define VIRTIO_CONFIG_S_ACKNOWLEDGE 1
#define VIRTIO_CONFIG_S_DRIVER 2
#define VIRTIO_CONFIG_S_DRIVER_OK 4
#define VIRTIO_CONFIG_S_FAILED 0x80
//
// Ring descriptor flags
//
#define VRING_DESC_F_NEXT 1 // Buffer continues via the next field
#define VRING_DESC_F_WRITE 2 // Buffer is write-only (otherwise read-only)
#define VRING_DESC_F_INDIRECT 4 // Buffer contains a list of buffer descriptors
//
// Ring descriptors for virtio
//
struct vring_desc {
unsigned __int64 addr;
unsigned long len;
unsigned short flags;
unsigned short next;
};
#define VRING_AVAIL_F_NO_INTERRUPT 1
struct vring_avail {
unsigned short flags;
unsigned short idx;
unsigned short ring[0];
};
struct vring_used_elem {
unsigned long id;
unsigned long len;
};
#define VRING_USED_F_NO_NOTIFY 1
struct vring_used {
unsigned short flags;
unsigned short idx;
struct vring_used_elem ring[0];
};
struct vring {
unsigned int size;
struct vring_desc *desc;
struct vring_avail *avail;
struct vring_used *used;
};
//
// Virtual queue
//
struct virtio_device;
typedef int (*virtio_callback_t)(struct virtio_queue *vq);
struct virtio_queue {
struct vring vring; // Ring for storing queue data
unsigned int num_free; // Number of free buffers
unsigned int free_head; // Head of free buffer list
unsigned int num_added; // Elements added since last sync
unsigned short last_used_idx; // Last used index seen
unsigned short index; // Queue index
struct virtio_device *vd; // Device this queue belongs to
struct virtio_queue *next; // Next queue for device
struct event bufavail; // Event for tracking free buffers
virtio_callback_t callback; // Callback for notifying about completion
void **data; // Tokens for callbacks
};
//
// Virtual I/O device
//
struct virtio_device {
struct unit *unit;
int irq;
int iobase;
struct interrupt intr;
struct dpc dpc;
unsigned long features;
struct virtio_queue *queues;
};
//
// Scatter-gather buffer list element
//
struct scatterlist {
void *data;
int size;
};
//
// Virtual I/O API
//
krnlapi int virtio_device_init(struct virtio_device *vd, struct unit *unit, int features);
krnlapi void virtio_setup_complete(struct virtio_device *vd, int success);
krnlapi void virtio_get_config(struct virtio_device *vd, void *buf, int len);
krnlapi int virtio_queue_init(struct virtio_queue *vq, struct virtio_device *vd, int index, virtio_callback_t callback);
krnlapi int virtio_queue_size(struct virtio_queue *vq);
krnlapi int virtio_enqueue(struct virtio_queue *vq, struct scatterlist sg[], unsigned int out, unsigned int in, void *data);
krnlapi void virtio_kick(struct virtio_queue *vq);
krnlapi void *virtio_dequeue(struct virtio_queue *vq, unsigned int *len);
#endif