1562 Integrate the virtio core module

[illumos-gate.git] / usr / src / uts / common / io / virtio / virtio.c

/*
 * 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));
}