io/virtio/virtio.c

	virtio.c revision e0724c534a46ca4754330bc022bf1e2a68f5bb93
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2012 Nexenta Systems, Inc.
 * Copyright 2012 Alexey Zaytsev <alexey.zaytsev@gmail.com>
 */

/* Based on the NetBSD virtio driver by Minoura Makoto. */
/*
 * Copyright (c) 2010 Minoura Makoto.
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 *
 */

#include <sys/conf.h>
#include <sys/kmem.h>
#include <sys/debug.h>
#include <sys/modctl.h>
#include <sys/autoconf.h>
#include <sys/ddi_impldefs.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/sunndi.h>
#include <sys/avintr.h>
#include <sys/spl.h>
#include <sys/promif.h>
#include <sys/list.h>
#include <sys/bootconf.h>
#include <sys/bootsvcs.h>
#include <sys/sysmacros.h>
#include <sys/pci.h>

#include "virtiovar.h"
#include "virtioreg.h"
#define NDEVNAMES   (sizeof (virtio_device_name) / sizeof (char *))
#define MINSEG_INDIRECT 2   /* use indirect if nsegs >= this value */
#define VIRTQUEUE_ALIGN(n) (((n)+(VIRTIO_PAGE_SIZE-1)) & \
        ~(VIRTIO_PAGE_SIZE-1))

void
virtio_set_status(struct virtio_softc *sc, unsigned int status)
{
    int old = 0;

    if (status != 0)
        old = ddi_get8(sc->sc_ioh,
            (uint8_t *)(sc->sc_io_addr +
            VIRTIO_CONFIG_DEVICE_STATUS));

    ddi_put8(sc->sc_ioh,
        (uint8_t *)(sc->sc_io_addr + VIRTIO_CONFIG_DEVICE_STATUS),
        status | old);
}

/*
 * Negotiate features, save the result in sc->sc_features
 */
uint32_t
virtio_negotiate_features(struct virtio_softc *sc, uint32_t guest_features)
{
    uint32_t host_features;
    uint32_t features;

    host_features = ddi_get32(sc->sc_ioh,
        /* LINTED E_BAD_PTR_CAST_ALIGN */
        (uint32_t *)(sc->sc_io_addr + VIRTIO_CONFIG_DEVICE_FEATURES));

    dev_debug(sc->sc_dev, CE_NOTE,
        "host features: %x, guest features: %x",
        host_features, guest_features);

    features = host_features & guest_features;
    ddi_put32(sc->sc_ioh,
        /* LINTED E_BAD_PTR_CAST_ALIGN */
        (uint32_t *)(sc->sc_io_addr + VIRTIO_CONFIG_GUEST_FEATURES),
        features);

    sc->sc_features = features;

    return (host_features);
}

size_t
virtio_show_features(uint32_t features,
    char *buf, size_t len)
{
    char *orig_buf = buf;
    char *bufend = buf + len;

    /* LINTED E_PTRDIFF_OVERFLOW */
    buf += snprintf(buf, bufend - buf, "Generic ( ");
    if (features & VIRTIO_F_RING_INDIRECT_DESC)
        /* LINTED E_PTRDIFF_OVERFLOW */
        buf += snprintf(buf, bufend - buf, "INDIRECT_DESC ");

    /* LINTED E_PTRDIFF_OVERFLOW */
    buf += snprintf(buf, bufend - buf, ") ");

    /* LINTED E_PTRDIFF_OVERFLOW */
    return (buf - orig_buf);
}

boolean_t
virtio_has_feature(struct virtio_softc *sc, uint32_t feature)
{
    return (sc->sc_features & feature);
}

/*
 * Device configuration registers.
 */
uint8_t
virtio_read_device_config_1(struct virtio_softc *sc, unsigned int index)
{
    ASSERT(sc->sc_config_offset);
    return ddi_get8(sc->sc_ioh,
        (uint8_t *)(sc->sc_io_addr + sc->sc_config_offset + index));
}

uint16_t
virtio_read_device_config_2(struct virtio_softc *sc, unsigned int index)
{
    ASSERT(sc->sc_config_offset);
    return ddi_get16(sc->sc_ioh,
        /* LINTED E_BAD_PTR_CAST_ALIGN */
        (uint16_t *)(sc->sc_io_addr + sc->sc_config_offset + index));
}

uint32_t
virtio_read_device_config_4(struct virtio_softc *sc, unsigned int index)
{
    ASSERT(sc->sc_config_offset);
    return ddi_get32(sc->sc_ioh,
        /* LINTED E_BAD_PTR_CAST_ALIGN */
        (uint32_t *)(sc->sc_io_addr + sc->sc_config_offset + index));
}

uint64_t
virtio_read_device_config_8(struct virtio_softc *sc, unsigned int index)
{
    uint64_t r;

    ASSERT(sc->sc_config_offset);
    r = ddi_get32(sc->sc_ioh,
        /* LINTED E_BAD_PTR_CAST_ALIGN */
        (uint32_t *)(sc->sc_io_addr + sc->sc_config_offset +
        index + sizeof (uint32_t)));

    r <<= 32;

    r += ddi_get32(sc->sc_ioh,
        /* LINTED E_BAD_PTR_CAST_ALIGN */
        (uint32_t *)(sc->sc_io_addr + sc->sc_config_offset + index));
    return (r);
}

void
virtio_write_device_config_1(struct virtio_softc *sc,
    unsigned int index, uint8_t value)
{
    ASSERT(sc->sc_config_offset);
    ddi_put8(sc->sc_ioh,
        (uint8_t *)(sc->sc_io_addr + sc->sc_config_offset + index), value);
}

void
virtio_write_device_config_2(struct virtio_softc *sc,
    unsigned int index, uint16_t value)
{
    ASSERT(sc->sc_config_offset);
    ddi_put16(sc->sc_ioh,
        /* LINTED E_BAD_PTR_CAST_ALIGN */
        (uint16_t *)(sc->sc_io_addr + sc->sc_config_offset + index), value);
}

void
virtio_write_device_config_4(struct virtio_softc *sc,
    unsigned int index, uint32_t value)
{
    ASSERT(sc->sc_config_offset);
    ddi_put32(sc->sc_ioh,
        /* LINTED E_BAD_PTR_CAST_ALIGN */
        (uint32_t *)(sc->sc_io_addr + sc->sc_config_offset + index), value);
}

void
virtio_write_device_config_8(struct virtio_softc *sc,
    unsigned int index, uint64_t value)
{
    ASSERT(sc->sc_config_offset);
    ddi_put32(sc->sc_ioh,
        /* LINTED E_BAD_PTR_CAST_ALIGN */
        (uint32_t *)(sc->sc_io_addr + sc->sc_config_offset + index),
        value & 0xFFFFFFFF);
    ddi_put32(sc->sc_ioh,
        /* LINTED E_BAD_PTR_CAST_ALIGN */
        (uint32_t *)(sc->sc_io_addr + sc->sc_config_offset +
        index + sizeof (uint32_t)), value >> 32);
}

/*
 * Start/stop vq interrupt.  No guarantee.
 */
void
virtio_stop_vq_intr(struct virtqueue *vq)
{
    vq->vq_avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
}

void
virtio_start_vq_intr(struct virtqueue *vq)
{
    vq->vq_avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT;
}

static ddi_dma_attr_t virtio_vq_dma_attr = {
    DMA_ATTR_V0,    /* Version number */
    0,      /* low address */
    /*
     * high address. Has to fit into 32 bits
     * after page-shifting
     */
    0x00000FFFFFFFFFFF,
    0xFFFFFFFF, /* counter register max */
    VIRTIO_PAGE_SIZE, /* page alignment required */
    0x3F,       /* burst sizes: 1 - 32 */
    0x1,        /* minimum transfer size */
    0xFFFFFFFF, /* max transfer size */
    0xFFFFFFFF, /* address register max */
    1,      /* no scatter-gather */
    1,      /* device operates on bytes */
    0,      /* attr flag: set to 0 */
};

static ddi_dma_attr_t virtio_vq_indirect_dma_attr = {
    DMA_ATTR_V0,    /* Version number */
    0,      /* low address */
    0xFFFFFFFFFFFFFFFF, /* high address */
    0xFFFFFFFF, /* counter register max */
    1,      /* No specific alignment */
    0x3F,       /* burst sizes: 1 - 32 */
    0x1,        /* minimum transfer size */
    0xFFFFFFFF, /* max transfer size */
    0xFFFFFFFF, /* address register max */
    1,      /* no scatter-gather */
    1,      /* device operates on bytes */
    0,      /* attr flag: set to 0 */
};

/* Same for direct and indirect descriptors. */
static ddi_device_acc_attr_t virtio_vq_devattr = {
    DDI_DEVICE_ATTR_V0,
    DDI_NEVERSWAP_ACC,
    DDI_STORECACHING_OK_ACC,
    DDI_DEFAULT_ACC
};

static void
virtio_free_indirect(struct vq_entry *entry)
{

    (void) ddi_dma_unbind_handle(entry->qe_indirect_dma_handle);
    ddi_dma_mem_free(&entry->qe_indirect_dma_acch);
    ddi_dma_free_handle(&entry->qe_indirect_dma_handle);

    entry->qe_indirect_descs = NULL;
}


static int
virtio_alloc_indirect(struct virtio_softc *sc, struct vq_entry *entry)
{
    int allocsize, num;
    size_t len;
    unsigned int ncookies;
    int ret;

    num = entry->qe_queue->vq_indirect_num;
    ASSERT(num > 1);

    allocsize = sizeof (struct vring_desc) * num;

    ret = ddi_dma_alloc_handle(sc->sc_dev, &virtio_vq_indirect_dma_attr,
        DDI_DMA_SLEEP, NULL, &entry->qe_indirect_dma_handle);
    if (ret != DDI_SUCCESS) {
        dev_err(sc->sc_dev, CE_WARN,
            "Failed to allocate dma handle for indirect descriptors,"
            " entry %d, vq %d", entry->qe_index,
            entry->qe_queue->vq_index);
        goto out_alloc_handle;
    }

    ret = ddi_dma_mem_alloc(entry->qe_indirect_dma_handle,
        allocsize, &virtio_vq_devattr,
        DDI_DMA_CONSISTENT, DDI_DMA_SLEEP, NULL,
        (caddr_t *)&entry->qe_indirect_descs, &len,
        &entry->qe_indirect_dma_acch);
    if (ret != DDI_SUCCESS) {
        dev_err(sc->sc_dev, CE_WARN,
            "Failed to alocate dma memory for indirect descriptors,"
            " entry %d, vq %d,", entry->qe_index,
            entry->qe_queue->vq_index);
        goto out_alloc;
    }

    (void) memset(entry->qe_indirect_descs, 0xff, allocsize);

    ret = ddi_dma_addr_bind_handle(entry->qe_indirect_dma_handle, NULL,
        (caddr_t)entry->qe_indirect_descs, len,
        DDI_DMA_RDWR | DDI_DMA_CONSISTENT,
        DDI_DMA_SLEEP, NULL, &entry->qe_indirect_dma_cookie, &ncookies);
    if (ret != DDI_DMA_MAPPED) {
        dev_err(sc->sc_dev, CE_WARN,
            "Failed to bind dma memory for indirect descriptors,"
            "entry %d, vq %d", entry->qe_index,
            entry->qe_queue->vq_index);
        goto out_bind;
    }

    /* We asked for a single segment */
    ASSERT(ncookies == 1);

    return (0);

out_bind:
    ddi_dma_mem_free(&entry->qe_indirect_dma_acch);
out_alloc:
    ddi_dma_free_handle(&entry->qe_indirect_dma_handle);
out_alloc_handle:

    return (ret);
}

/*
 * Initialize the vq structure.
 */
static int
virtio_init_vq(struct virtio_softc *sc, struct virtqueue *vq)
{
    int ret;
    uint16_t i;
    int vq_size = vq->vq_num;
    int indirect_num = vq->vq_indirect_num;

    /* free slot management */
    list_create(&vq->vq_freelist, sizeof (struct vq_entry),
        offsetof(struct vq_entry, qe_list));

    for (i = 0; i < vq_size; i++) {
        struct vq_entry *entry = &vq->vq_entries[i];
        list_insert_tail(&vq->vq_freelist, entry);
        entry->qe_index = i;
        entry->qe_desc = &vq->vq_descs[i];
        entry->qe_queue = vq;

        if (indirect_num) {
            ret = virtio_alloc_indirect(sc, entry);
            if (ret)
                goto out_indirect;
        }
    }

    mutex_init(&vq->vq_freelist_lock, "virtio-freelist",
        MUTEX_DRIVER, DDI_INTR_PRI(sc->sc_intr_prio));
    mutex_init(&vq->vq_avail_lock, "virtio-avail",
        MUTEX_DRIVER, DDI_INTR_PRI(sc->sc_intr_prio));
    mutex_init(&vq->vq_used_lock, "virtio-used",
        MUTEX_DRIVER, DDI_INTR_PRI(sc->sc_intr_prio));

    return (0);

out_indirect:
    for (i = 0; i < vq_size; i++) {
        struct vq_entry *entry = &vq->vq_entries[i];
        if (entry->qe_indirect_descs)
            virtio_free_indirect(entry);
    }

    return (ret);
}


/*
 * Allocate/free a vq.
 */
struct virtqueue *
virtio_alloc_vq(struct virtio_softc *sc,
    unsigned int index,
    unsigned int size,
    unsigned int indirect_num,
    const char *name)
{
    int vq_size, allocsize1, allocsize2, allocsize = 0;
    int ret;
    unsigned int ncookies;
    size_t len;
    struct virtqueue *vq;


    ddi_put16(sc->sc_ioh,
        /* LINTED E_BAD_PTR_CAST_ALIGN */
        (uint16_t *)(sc->sc_io_addr + VIRTIO_CONFIG_QUEUE_SELECT), index);
    vq_size = ddi_get16(sc->sc_ioh,
        /* LINTED E_BAD_PTR_CAST_ALIGN */
        (uint16_t *)(sc->sc_io_addr + VIRTIO_CONFIG_QUEUE_SIZE));
    if (vq_size == 0) {
        dev_err(sc->sc_dev, CE_WARN,
            "virtqueue dest not exist, index %d for %s\n", index, name);
        goto out;
    }

    vq = kmem_zalloc(sizeof (struct virtqueue), KM_SLEEP);

    /* size 0 => use native vq size, good for receive queues. */
    if (size)
        vq_size = MIN(vq_size, size);

    /* allocsize1: descriptor table + avail ring + pad */
    allocsize1 = VIRTQUEUE_ALIGN(sizeof (struct vring_desc) * vq_size +
        sizeof (struct vring_avail) +
        sizeof (uint16_t) * vq_size);
    /* allocsize2: used ring + pad */
    allocsize2 = VIRTQUEUE_ALIGN(sizeof (struct vring_used)
        + sizeof (struct vring_used_elem) * vq_size);

    allocsize = allocsize1 + allocsize2;

    ret = ddi_dma_alloc_handle(sc->sc_dev, &virtio_vq_dma_attr,
        DDI_DMA_SLEEP, NULL, &vq->vq_dma_handle);
    if (ret != DDI_SUCCESS) {
        dev_err(sc->sc_dev, CE_WARN,
            "Failed to allocate dma handle for vq %d", index);
        goto out_alloc_handle;
    }

    ret = ddi_dma_mem_alloc(vq->vq_dma_handle, allocsize,
        &virtio_vq_devattr, DDI_DMA_CONSISTENT, DDI_DMA_SLEEP, NULL,
        (caddr_t *)&vq->vq_vaddr, &len, &vq->vq_dma_acch);
    if (ret != DDI_SUCCESS) {
        dev_err(sc->sc_dev, CE_WARN,
            "Failed to alocate dma memory for vq %d", index);
        goto out_alloc;
    }


    ret = ddi_dma_addr_bind_handle(vq->vq_dma_handle, NULL,
        (caddr_t)vq->vq_vaddr, len,
        DDI_DMA_RDWR | DDI_DMA_CONSISTENT,
        DDI_DMA_SLEEP, NULL, &vq->vq_dma_cookie, &ncookies);
    if (ret != DDI_DMA_MAPPED) {
        dev_err(sc->sc_dev, CE_WARN,
            "Failed to bind dma memory for vq %d", index);
        goto out_bind;
    }

    /* We asked for a single segment */
    ASSERT(ncookies == 1);
    /* and page-ligned buffers. */
    ASSERT(vq->vq_dma_cookie.dmac_laddress % VIRTIO_PAGE_SIZE == 0);

    (void) memset(vq->vq_vaddr, 0, allocsize);

    /* Make sure all zeros hit the buffer before we point the host to it */
    membar_producer();

    /* set the vq address */
    ddi_put32(sc->sc_ioh,
        /* LINTED E_BAD_PTR_CAST_ALIGN */
        (uint32_t *)(sc->sc_io_addr + VIRTIO_CONFIG_QUEUE_ADDRESS),
        (vq->vq_dma_cookie.dmac_laddress / VIRTIO_PAGE_SIZE));

    /* remember addresses and offsets for later use */
    vq->vq_owner = sc;
    vq->vq_num = vq_size;
    vq->vq_index = index;
    vq->vq_descs = vq->vq_vaddr;
    vq->vq_availoffset = sizeof (struct vring_desc)*vq_size;
    vq->vq_avail = (void *)(((char *)vq->vq_descs) + vq->vq_availoffset);
    vq->vq_usedoffset = allocsize1;
    vq->vq_used = (void *)(((char *)vq->vq_descs) + vq->vq_usedoffset);

    ASSERT(indirect_num == 0 ||
        virtio_has_feature(sc, VIRTIO_F_RING_INDIRECT_DESC));
    vq->vq_indirect_num = indirect_num;

    /* free slot management */
    vq->vq_entries = kmem_zalloc(sizeof (struct vq_entry) * vq_size,
        KM_SLEEP);

    ret = virtio_init_vq(sc, vq);
    if (ret)
        goto out_init;

    dev_debug(sc->sc_dev, CE_NOTE,
        "Allocated %d entries for vq %d:%s (%d incdirect descs)",
        vq_size, index, name, indirect_num * vq_size);

    return (vq);

out_init:
    kmem_free(vq->vq_entries, sizeof (struct vq_entry) * vq_size);
    (void) ddi_dma_unbind_handle(vq->vq_dma_handle);
out_bind:
    ddi_dma_mem_free(&vq->vq_dma_acch);
out_alloc:
    ddi_dma_free_handle(&vq->vq_dma_handle);
out_alloc_handle:
    kmem_free(vq, sizeof (struct virtqueue));
out:
    return (NULL);
}


void
virtio_free_vq(struct virtqueue *vq)
{
    struct virtio_softc *sc = vq->vq_owner;
    int i;

    /* tell device that there's no virtqueue any longer */
    ddi_put16(sc->sc_ioh,
        /* LINTED E_BAD_PTR_CAST_ALIGN */
        (uint16_t *)(sc->sc_io_addr + VIRTIO_CONFIG_QUEUE_SELECT),
        vq->vq_index);
    ddi_put32(sc->sc_ioh,
        /* LINTED E_BAD_PTR_CAST_ALIGN */
        (uint32_t *)(sc->sc_io_addr + VIRTIO_CONFIG_QUEUE_ADDRESS), 0);

    /* Free the indirect descriptors, if any. */
    for (i = 0; i < vq->vq_num; i++) {
        struct vq_entry *entry = &vq->vq_entries[i];
        if (entry->qe_indirect_descs)
            virtio_free_indirect(entry);
    }

    kmem_free(vq->vq_entries, sizeof (struct vq_entry) * vq->vq_num);

    (void) ddi_dma_unbind_handle(vq->vq_dma_handle);
    ddi_dma_mem_free(&vq->vq_dma_acch);
    ddi_dma_free_handle(&vq->vq_dma_handle);

    mutex_destroy(&vq->vq_used_lock);
    mutex_destroy(&vq->vq_avail_lock);
    mutex_destroy(&vq->vq_freelist_lock);

    kmem_free(vq, sizeof (struct virtqueue));
}

/*
 * Free descriptor management.
 */
struct vq_entry *
vq_alloc_entry(struct virtqueue *vq)
{
    struct vq_entry *qe;

    mutex_enter(&vq->vq_freelist_lock);
    if (list_is_empty(&vq->vq_freelist)) {
        mutex_exit(&vq->vq_freelist_lock);
        return (NULL);
    }
    qe = list_remove_head(&vq->vq_freelist);

    ASSERT(vq->vq_used_entries >= 0);
    vq->vq_used_entries++;

    mutex_exit(&vq->vq_freelist_lock);

    qe->qe_next = NULL;
    qe->qe_indirect_next = 0;
    (void) memset(qe->qe_desc, 0, sizeof (struct vring_desc));

    return (qe);
}

void
vq_free_entry(struct virtqueue *vq, struct vq_entry *qe)
{
    mutex_enter(&vq->vq_freelist_lock);

    list_insert_head(&vq->vq_freelist, qe);
    vq->vq_used_entries--;
    ASSERT(vq->vq_used_entries >= 0);
    mutex_exit(&vq->vq_freelist_lock);
}

/*
 * We (intentionally) don't have a global vq mutex, so you are
 * responsible for external locking to avoid allocting/freeing any
 * entries before using the returned value. Have fun.
 */
uint_t
vq_num_used(struct virtqueue *vq)
{
    /* vq->vq_freelist_lock would not help here. */
    return (vq->vq_used_entries);
}

static inline void
virtio_ve_set_desc(struct vring_desc *desc, uint64_t paddr, uint32_t len,
    boolean_t write)
{
    desc->addr = paddr;
    desc->len = len;
    desc->next = 0;
    desc->flags = 0;

    /* 'write' - from the driver's point of view */
    if (!write)
        desc->flags = VRING_DESC_F_WRITE;


}

void
virtio_ve_set(struct vq_entry *qe, uint64_t paddr, uint32_t len,
    boolean_t write)
{
    virtio_ve_set_desc(qe->qe_desc, paddr, len, write);
}

void
virtio_ve_add_indirect_buf(struct vq_entry *qe, uint64_t paddr, uint32_t len,
    boolean_t write)
{
    struct vring_desc *indirect_desc;

    ASSERT(qe->qe_queue->vq_indirect_num);
    ASSERT(qe->qe_indirect_next < qe->qe_queue->vq_indirect_num);

    indirect_desc = &qe->qe_indirect_descs[qe->qe_indirect_next];
    virtio_ve_set_desc(indirect_desc, paddr, len, write);
    qe->qe_indirect_next++;
}

void
virtio_ve_add_cookie(struct vq_entry *qe, ddi_dma_handle_t dma_handle,
    ddi_dma_cookie_t dma_cookie, unsigned int ncookies, boolean_t write)
{
    int i;

    for (i = 0; i < ncookies; i++) {
        virtio_ve_add_indirect_buf(qe, dma_cookie.dmac_laddress,
            dma_cookie.dmac_size, write);
        ddi_dma_nextcookie(dma_handle, &dma_cookie);
    }
}

void
virtio_sync_vq(struct virtqueue *vq)
{
    struct virtio_softc *vsc = vq->vq_owner;

    /* Make sure the avail ring update hit the buffer */
    membar_producer();

    vq->vq_avail->idx = vq->vq_avail_idx;

    /* Make sure the avail idx update hits the buffer */
    membar_producer();

    /* Make sure we see the flags update */
    membar_consumer();

    if (!(vq->vq_used->flags & VRING_USED_F_NO_NOTIFY))
        ddi_put16(vsc->sc_ioh,
            /* LINTED E_BAD_PTR_CAST_ALIGN */
            (uint16_t *)(vsc->sc_io_addr +
            VIRTIO_CONFIG_QUEUE_NOTIFY),
            vq->vq_index);
}

void
virtio_push_chain(struct vq_entry *qe, boolean_t sync)
{
    struct virtqueue *vq = qe->qe_queue;
    struct vq_entry *head = qe;
    struct vring_desc *desc;
    int idx;

    ASSERT(qe);

    /*
     * Bind the descs together, paddr and len should be already
     * set with virtio_ve_set
     */
    do {
        /* Bind the indirect descriptors */
        if (qe->qe_indirect_next > 1) {
            uint16_t i = 0;

            /*
             * Set the pointer/flags to the
             * first indirect descriptor
             */
            virtio_ve_set_desc(qe->qe_desc,
                qe->qe_indirect_dma_cookie.dmac_laddress,
                sizeof (struct vring_desc) * qe->qe_indirect_next,
                B_FALSE);
            qe->qe_desc->flags |= VRING_DESC_F_INDIRECT;

            /* For all but the last one, add the next index/flag */
            do {
                desc = &qe->qe_indirect_descs[i];
                i++;

                desc->flags |= VRING_DESC_F_NEXT;
                desc->next = i;
            } while (i < qe->qe_indirect_next - 1);

        }

        if (qe->qe_next) {
            qe->qe_desc->flags |= VRING_DESC_F_NEXT;
            qe->qe_desc->next = qe->qe_next->qe_index;
        }

        qe = qe->qe_next;
    } while (qe);

    mutex_enter(&vq->vq_avail_lock);
    idx = vq->vq_avail_idx;
    vq->vq_avail_idx++;

    /* Make sure the bits hit the descriptor(s) */
    membar_producer();
    vq->vq_avail->ring[idx % vq->vq_num] = head->qe_index;

    /* Notify the device, if needed. */
    if (sync)
        virtio_sync_vq(vq);

    mutex_exit(&vq->vq_avail_lock);
}

/* Get a chain of descriptors from the used ring, if one is available. */
struct vq_entry *
virtio_pull_chain(struct virtqueue *vq, uint32_t *len)
{
    struct vq_entry *head;
    int slot;
    int usedidx;

    mutex_enter(&vq->vq_used_lock);

    /* No used entries? Bye. */
    if (vq->vq_used_idx == vq->vq_used->idx) {
        mutex_exit(&vq->vq_used_lock);
        return (NULL);
    }

    usedidx = vq->vq_used_idx;
    vq->vq_used_idx++;
    mutex_exit(&vq->vq_used_lock);

    usedidx %= vq->vq_num;

    /* Make sure we do the next step _after_ checking the idx. */
    membar_consumer();

    slot = vq->vq_used->ring[usedidx].id;
    *len = vq->vq_used->ring[usedidx].len;

    head = &vq->vq_entries[slot];

    return (head);
}

void
virtio_free_chain(struct vq_entry *qe)
{
    struct vq_entry *tmp;
    struct virtqueue *vq = qe->qe_queue;

    ASSERT(qe);

    do {
        ASSERT(qe->qe_queue == vq);
        tmp = qe->qe_next;
        vq_free_entry(vq, qe);
        qe = tmp;
    } while (tmp);
}

void
virtio_ventry_stick(struct vq_entry *first, struct vq_entry *second)
{
    first->qe_next = second;
}

static int
virtio_register_msi(struct virtio_softc *sc,
    struct virtio_int_handler *config_handler,
    struct virtio_int_handler vq_handlers[],
    int intr_types)
{
    int count, actual;
    int int_type;
    int i;
    int handler_count;
    int ret;

    /* If both MSI and MSI-x are reported, prefer MSI-x. */
    int_type = DDI_INTR_TYPE_MSI;
    if (intr_types & DDI_INTR_TYPE_MSIX)
        int_type = DDI_INTR_TYPE_MSIX;

    /* Walk the handler table to get the number of handlers. */
    for (handler_count = 0;
        vq_handlers && vq_handlers[handler_count].vh_func;
        handler_count++)
        ;

    /* +1 if there is a config change handler. */
    if (config_handler)
        handler_count++;

    /* Number of MSIs supported by the device. */
    ret = ddi_intr_get_nintrs(sc->sc_dev, int_type, &count);
    if (ret != DDI_SUCCESS) {
        dev_err(sc->sc_dev, CE_WARN, "ddi_intr_get_nintrs failed");
        return (ret);
    }

    /*
     * Those who try to register more handlers then the device
     * supports shall suffer.
     */
    ASSERT(handler_count <= count);

    sc->sc_intr_htable = kmem_zalloc(
        sizeof (ddi_intr_handle_t) * handler_count, KM_SLEEP);

    ret = ddi_intr_alloc(sc->sc_dev, sc->sc_intr_htable, int_type, 0,
        handler_count, &actual, DDI_INTR_ALLOC_NORMAL);
    if (ret != DDI_SUCCESS) {
        dev_err(sc->sc_dev, CE_WARN, "Failed to allocate MSI: %d", ret);
        goto out_msi_alloc;
    }

    if (actual != handler_count) {
        dev_err(sc->sc_dev, CE_WARN,
            "Not enough MSI available: need %d, available %d",
            handler_count, actual);
        goto out_msi_available;
    }

    sc->sc_intr_num = handler_count;
    sc->sc_intr_config = B_FALSE;
    if (config_handler) {
        sc->sc_intr_config = B_TRUE;
    }

    /* Assume they are all same priority */
    ret = ddi_intr_get_pri(sc->sc_intr_htable[0], &sc->sc_intr_prio);
    if (ret != DDI_SUCCESS) {
        dev_err(sc->sc_dev, CE_WARN, "ddi_intr_get_pri failed");
        goto out_msi_prio;
    }

    /* Add the vq handlers */
    for (i = 0; vq_handlers[i].vh_func; i++) {
        ret = ddi_intr_add_handler(sc->sc_intr_htable[i],
            vq_handlers[i].vh_func,
            sc, vq_handlers[i].vh_priv);
        if (ret != DDI_SUCCESS) {
            dev_err(sc->sc_dev, CE_WARN,
                "ddi_intr_add_handler failed");
            /* Remove the handlers that succeeded. */
            while (--i >= 0) {
                (void) ddi_intr_remove_handler(
                    sc->sc_intr_htable[i]);
            }
            goto out_add_handlers;
        }
    }

    /* Don't forget the config handler */
    if (config_handler) {
        ret = ddi_intr_add_handler(sc->sc_intr_htable[i],
            config_handler->vh_func,
            sc, config_handler->vh_priv);
        if (ret != DDI_SUCCESS) {
            dev_err(sc->sc_dev, CE_WARN,
                "ddi_intr_add_handler failed");
            /* Remove the handlers that succeeded. */
            while (--i >= 0) {
                (void) ddi_intr_remove_handler(
                    sc->sc_intr_htable[i]);
            }
            goto out_add_handlers;
        }
    }

    /* We know we are using MSI, so set the config offset. */
    sc->sc_config_offset = VIRTIO_CONFIG_DEVICE_CONFIG_MSI;

    ret = ddi_intr_get_cap(sc->sc_intr_htable[0],
        &sc->sc_intr_cap);
    /* Just in case. */
    if (ret != DDI_SUCCESS)
        sc->sc_intr_cap = 0;

out_add_handlers:
out_msi_prio:
out_msi_available:
    for (i = 0; i < actual; i++)
        (void) ddi_intr_free(sc->sc_intr_htable[i]);
out_msi_alloc:
    kmem_free(sc->sc_intr_htable, sizeof (ddi_intr_handle_t) * count);

    return (ret);
}

struct virtio_handler_container {
    int nhandlers;
    struct virtio_int_handler config_handler;
    struct virtio_int_handler vq_handlers[];
};

uint_t
virtio_intx_dispatch(caddr_t arg1, caddr_t arg2)
{
    struct virtio_softc *sc = (void *)arg1;
    struct virtio_handler_container *vhc = (void *)arg2;
    uint8_t isr_status;
    int i;

    isr_status = ddi_get8(sc->sc_ioh, (uint8_t *)(sc->sc_io_addr +
        VIRTIO_CONFIG_ISR_STATUS));

    if (!isr_status)
        return (DDI_INTR_UNCLAIMED);

    if ((isr_status & VIRTIO_CONFIG_ISR_CONFIG_CHANGE) &&
        vhc->config_handler.vh_func) {
        vhc->config_handler.vh_func((void *)sc,
            vhc->config_handler.vh_priv);
    }

    /* Notify all handlers */
    for (i = 0; i < vhc->nhandlers; i++) {
        vhc->vq_handlers[i].vh_func((void *)sc,
            vhc->vq_handlers[i].vh_priv);
    }

    return (DDI_INTR_CLAIMED);
}

/*
 * config_handler and vq_handlers may be allocated on stack.
 * Take precautions not to loose them.
 */
static int
virtio_register_intx(struct virtio_softc *sc,
    struct virtio_int_handler *config_handler,
    struct virtio_int_handler vq_handlers[])
{
    int vq_handler_count;
    int config_handler_count = 0;
    int actual;
    struct virtio_handler_container *vhc;
    int ret = DDI_FAILURE;

    /* Walk the handler table to get the number of handlers. */
    for (vq_handler_count = 0;
        vq_handlers && vq_handlers[vq_handler_count].vh_func;
        vq_handler_count++)
        ;

    if (config_handler)
        config_handler_count = 1;

    vhc = kmem_zalloc(sizeof (struct virtio_handler_container) +
        sizeof (struct virtio_int_handler) * vq_handler_count,
        KM_SLEEP);

    vhc->nhandlers = vq_handler_count;
    (void) memcpy(vhc->vq_handlers, vq_handlers,
        sizeof (struct virtio_int_handler) * vq_handler_count);

    if (config_handler) {
        (void) memcpy(&vhc->config_handler, config_handler,
            sizeof (struct virtio_int_handler));
    }

    /* Just a single entry for a single interrupt. */
    sc->sc_intr_htable = kmem_zalloc(sizeof (ddi_intr_handle_t), KM_SLEEP);

    ret = ddi_intr_alloc(sc->sc_dev, sc->sc_intr_htable,
        DDI_INTR_TYPE_FIXED, 0, 1, &actual,
        DDI_INTR_ALLOC_NORMAL);
    if (ret != DDI_SUCCESS) {
        dev_err(sc->sc_dev, CE_WARN,
            "Failed to allocate a fixed interrupt: %d", ret);
        goto out_int_alloc;
    }

    ASSERT(actual == 1);
    sc->sc_intr_num = 1;

    ret = ddi_intr_get_pri(sc->sc_intr_htable[0], &sc->sc_intr_prio);
    if (ret != DDI_SUCCESS) {
        dev_err(sc->sc_dev, CE_WARN, "ddi_intr_get_pri failed");
        goto out_prio;
    }

    ret = ddi_intr_add_handler(sc->sc_intr_htable[0],
        virtio_intx_dispatch, sc, vhc);
    if (ret != DDI_SUCCESS) {
        dev_err(sc->sc_dev, CE_WARN, "ddi_intr_add_handler failed");
        goto out_add_handlers;
    }

    /* We know we are not using MSI, so set the config offset. */
    sc->sc_config_offset = VIRTIO_CONFIG_DEVICE_CONFIG_NOMSI;

    return (DDI_SUCCESS);

out_add_handlers:
out_prio:
    (void) ddi_intr_free(sc->sc_intr_htable[0]);
out_int_alloc:
    kmem_free(sc->sc_intr_htable, sizeof (ddi_intr_handle_t));
    kmem_free(vhc, sizeof (struct virtio_int_handler) *
        (vq_handler_count + config_handler_count));
    return (ret);
}

/*
 * We find out if we support MSI during this, and the register layout
 * depends on the MSI (doh). Don't acces the device specific bits in
 * BAR 0 before calling it!
 */
int
virtio_register_ints(struct virtio_softc *sc,
    struct virtio_int_handler *config_handler,
    struct virtio_int_handler vq_handlers[])
{
    int ret;
    int intr_types;

    /* Determine which types of interrupts are supported */
    ret = ddi_intr_get_supported_types(sc->sc_dev, &intr_types);
    if (ret != DDI_SUCCESS) {
        dev_err(sc->sc_dev, CE_WARN, "Can't get supported int types");
        goto out_inttype;
    }

    /* If we have msi, let's use them. */
    if (intr_types & (DDI_INTR_TYPE_MSIX | DDI_INTR_TYPE_MSI)) {
        ret = virtio_register_msi(sc, config_handler,
            vq_handlers, intr_types);
        if (!ret)
            return (0);
    }

    /* Fall back to old-fashioned interrupts. */
    if (intr_types & DDI_INTR_TYPE_FIXED) {
        dev_debug(sc->sc_dev, CE_WARN,
            "Using legacy interrupts");

        return (virtio_register_intx(sc, config_handler, vq_handlers));
    }

    dev_err(sc->sc_dev, CE_WARN,
        "MSI failed and fixed interrupts not supported. Giving up.");
    ret = DDI_FAILURE;

out_inttype:
    return (ret);
}


static int
virtio_enable_msi(struct virtio_softc *sc)
{
    int ret, i;
    int vq_handler_count = sc->sc_intr_num;

    /* Number of handlers, not counting the counfig. */
    if (sc->sc_intr_config)
        vq_handler_count--;

    /* Enable the iterrupts. Either the whole block, or one by one. */
    if (sc->sc_intr_cap & DDI_INTR_FLAG_BLOCK) {
        ret = ddi_intr_block_enable(sc->sc_intr_htable,
            sc->sc_intr_num);
        if (ret != DDI_SUCCESS) {
            dev_err(sc->sc_dev, CE_WARN,
                "Failed to enable MSI, falling back to INTx");
            goto out_enable;
        }
    } else {
        for (i = 0; i < sc->sc_intr_num; i++) {
            ret = ddi_intr_enable(sc->sc_intr_htable[i]);
            if (ret != DDI_SUCCESS) {
                dev_err(sc->sc_dev, CE_WARN,
                    "Failed to enable MSI %d, "
                    "falling back to INTx", i);

                while (--i >= 0) {
                    (void) ddi_intr_disable(
                        sc->sc_intr_htable[i]);
                }
                goto out_enable;
            }
        }
    }

    /* Bind the allocated MSI to the queues and config */
    for (i = 0; i < vq_handler_count; i++) {
        int check;
        ddi_put16(sc->sc_ioh,
            /* LINTED E_BAD_PTR_CAST_ALIGN */
            (uint16_t *)(sc->sc_io_addr +
            VIRTIO_CONFIG_QUEUE_SELECT), i);

        ddi_put16(sc->sc_ioh,
            /* LINTED E_BAD_PTR_CAST_ALIGN */
            (uint16_t *)(sc->sc_io_addr +
            VIRTIO_CONFIG_QUEUE_VECTOR), i);

        check = ddi_get16(sc->sc_ioh,
            /* LINTED E_BAD_PTR_CAST_ALIGN */
            (uint16_t *)(sc->sc_io_addr +
            VIRTIO_CONFIG_QUEUE_VECTOR));
        if (check != i) {
            dev_err(sc->sc_dev, CE_WARN, "Failed to bind handler"
                "for VQ %d, MSI %d. Check = %x", i, i, check);
            ret = ENODEV;
            goto out_bind;
        }
    }

    if (sc->sc_intr_config) {
        int check;
        ddi_put16(sc->sc_ioh,
            /* LINTED E_BAD_PTR_CAST_ALIGN */
            (uint16_t *)(sc->sc_io_addr +
            VIRTIO_CONFIG_CONFIG_VECTOR), i);

        check = ddi_get16(sc->sc_ioh,
            /* LINTED E_BAD_PTR_CAST_ALIGN */
            (uint16_t *)(sc->sc_io_addr +
            VIRTIO_CONFIG_CONFIG_VECTOR));
        if (check != i) {
            dev_err(sc->sc_dev, CE_WARN, "Failed to bind handler "
                "for Config updates, MSI %d", i);
            ret = ENODEV;
            goto out_bind;
        }
    }

    return (DDI_SUCCESS);

out_bind:
    /* Unbind the vqs */
    for (i = 0; i < vq_handler_count - 1; i++) {
        ddi_put16(sc->sc_ioh,
            /* LINTED E_BAD_PTR_CAST_ALIGN */
            (uint16_t *)(sc->sc_io_addr +
            VIRTIO_CONFIG_QUEUE_SELECT), i);

        ddi_put16(sc->sc_ioh,
            /* LINTED E_BAD_PTR_CAST_ALIGN */
            (uint16_t *)(sc->sc_io_addr +
            VIRTIO_CONFIG_QUEUE_VECTOR),
            VIRTIO_MSI_NO_VECTOR);
    }
    /* And the config */
    /* LINTED E_BAD_PTR_CAST_ALIGN */
    ddi_put16(sc->sc_ioh, (uint16_t *)(sc->sc_io_addr +
        VIRTIO_CONFIG_CONFIG_VECTOR), VIRTIO_MSI_NO_VECTOR);

    ret = DDI_FAILURE;

out_enable:
    return (ret);
}

static int virtio_enable_intx(struct virtio_softc *sc)
{
    int ret;

    ret = ddi_intr_enable(sc->sc_intr_htable[0]);
    if (ret != DDI_SUCCESS)
        dev_err(sc->sc_dev, CE_WARN,
            "Failed to enable interrupt: %d", ret);
    return (ret);
}

/*
 * We can't enable/disable individual handlers in the INTx case so do
 * the whole bunch even in the msi case.
 */
int
virtio_enable_ints(struct virtio_softc *sc)
{

    /* See if we are using MSI. */
    if (sc->sc_config_offset == VIRTIO_CONFIG_DEVICE_CONFIG_MSI)
        return (virtio_enable_msi(sc));

    ASSERT(sc->sc_config_offset == VIRTIO_CONFIG_DEVICE_CONFIG_NOMSI);

    return (virtio_enable_intx(sc));
}

void
virtio_release_ints(struct virtio_softc *sc)
{
    int i;
    int ret;

    /* We were running with MSI, unbind them. */
    if (sc->sc_config_offset == VIRTIO_CONFIG_DEVICE_CONFIG_MSI) {
        /* Unbind all vqs */
        for (i = 0; i < sc->sc_nvqs; i++) {
            ddi_put16(sc->sc_ioh,
                /* LINTED E_BAD_PTR_CAST_ALIGN */
                (uint16_t *)(sc->sc_io_addr +
                VIRTIO_CONFIG_QUEUE_SELECT), i);

            ddi_put16(sc->sc_ioh,
                /* LINTED E_BAD_PTR_CAST_ALIGN */
                (uint16_t *)(sc->sc_io_addr +
                VIRTIO_CONFIG_QUEUE_VECTOR),
                VIRTIO_MSI_NO_VECTOR);
        }
        /* And the config */
        /* LINTED E_BAD_PTR_CAST_ALIGN */
        ddi_put16(sc->sc_ioh, (uint16_t *)(sc->sc_io_addr +
            VIRTIO_CONFIG_CONFIG_VECTOR),
            VIRTIO_MSI_NO_VECTOR);

    }

    /* Disable the iterrupts. Either the whole block, or one by one. */
    if (sc->sc_intr_cap & DDI_INTR_FLAG_BLOCK) {
        ret = ddi_intr_block_disable(sc->sc_intr_htable,
            sc->sc_intr_num);
        if (ret != DDI_SUCCESS) {
            dev_err(sc->sc_dev, CE_WARN,
                "Failed to disable MSIs, won't be able to"
                "reuse next time");
        }
    } else {
        for (i = 0; i < sc->sc_intr_num; i++) {
            ret = ddi_intr_disable(sc->sc_intr_htable[i]);
            if (ret != DDI_SUCCESS) {
                dev_err(sc->sc_dev, CE_WARN,
                    "Failed to disable interrupt %d, "
                    "won't be able to reuse", i);

            }
        }
    }


    for (i = 0; i < sc->sc_intr_num; i++) {
        (void) ddi_intr_remove_handler(sc->sc_intr_htable[i]);
    }

    for (i = 0; i < sc->sc_intr_num; i++)
        (void) ddi_intr_free(sc->sc_intr_htable[i]);

    kmem_free(sc->sc_intr_htable,
        sizeof (ddi_intr_handle_t) * sc->sc_intr_num);


    /* After disabling interrupts, the config offset is non-MSI. */
    sc->sc_config_offset = VIRTIO_CONFIG_DEVICE_CONFIG_NOMSI;
}

/*
 * Module linkage information for the kernel.
 */
static struct modlmisc modlmisc = {
    &mod_miscops, /* Type of module */
    "VirtIO common library module",
};

static struct modlinkage modlinkage = {
    MODREV_1,
    {
        (void *)&modlmisc,
        NULL
    }
};

int
_init(void)
{
    return (mod_install(&modlinkage));
}

int
_fini(void)
{
    return (mod_remove(&modlinkage));
}

int
_info(struct modinfo *modinfop)
{
    return (mod_info(&modlinkage, modinfop));
}