io/vmxnet3s/vmxnet3_rx.c

/*
 * Copyright (C) 2007 VMware, Inc. All rights reserved.
 *
 * The contents of this file are subject to the terms of the Common
 * Development and Distribution License (the "License") version 1.0
 * and no later version.  You may not use this file except in
 * compliance with the License.
 *
 * You can obtain a copy of the License at
 *         http://www.opensource.org/licenses/cddl1.php
 *
 * See the License for the specific language governing permissions
 * and limitations under the License.
 */
/*
 * Copyright (c) 2013, 2016 by Delphix. All rights reserved.
 */

#include <vmxnet3.h>

static void vmxnet3_put_rxbuf(vmxnet3_rxbuf_t *);

/*
 * Allocate a new rxBuf from memory. All its fields are set except
 * for its associated mblk which has to be allocated later.
 *
 * Returns:
 *  A new rxBuf or NULL.
 */
static vmxnet3_rxbuf_t *
vmxnet3_alloc_rxbuf(vmxnet3_softc_t *dp, boolean_t canSleep)
{
    vmxnet3_rxbuf_t *rxBuf;
    int flag = canSleep ? KM_SLEEP : KM_NOSLEEP;
    int err;

    rxBuf = kmem_zalloc(sizeof (vmxnet3_rxbuf_t), flag);
    if (!rxBuf) {
        atomic_inc_32(&dp->rx_alloc_failed);
        return (NULL);
    }

    if ((err = vmxnet3_alloc_dma_mem_1(dp, &rxBuf->dma, (dp->cur_mtu + 18),
        canSleep)) != 0) {
        VMXNET3_DEBUG(dp, 0, "Failed to allocate %d bytes for rx buf, "
            "err:%d\n", (dp->cur_mtu + 18), err);
        kmem_free(rxBuf, sizeof (vmxnet3_rxbuf_t));
        atomic_inc_32(&dp->rx_alloc_failed);
        return (NULL);
    }

    rxBuf->freeCB.free_func = vmxnet3_put_rxbuf;
    rxBuf->freeCB.free_arg = (caddr_t)rxBuf;
    rxBuf->dp = dp;

    atomic_inc_32(&dp->rx_num_bufs);
    atomic_inc_32(&dp->rx_alloc_buf);
    return (rxBuf);
}

static void
vmxnet3_free_rxbuf(vmxnet3_softc_t *dp, vmxnet3_rxbuf_t *rxBuf)
{
    vmxnet3_free_dma_mem(&rxBuf->dma);
    kmem_free(rxBuf, sizeof (vmxnet3_rxbuf_t));

#ifndef DEBUG
    atomic_dec_32(&dp->rx_num_bufs);
#else
    {
        uint32_t nv = atomic_dec_32_nv(&dp->rx_num_bufs);
        ASSERT(nv != (uint32_t)-1);
    }
#endif
}

/*
 * Return a rxBuf to the pool. The init argument, when B_TRUE, indicates
 * that we're being called for the purpose of pool initialization, and
 * therefore, we should place the buffer in the pool even if the device
 * isn't enabled.
 *
 * Returns:
 *  B_TRUE if the buffer was returned to the pool, or B_FALSE if it
 *  wasn't (e.g. if the device is stopped).
 */
static boolean_t
vmxnet3_put_rxpool_buf(vmxnet3_softc_t *dp, vmxnet3_rxbuf_t *rxBuf,
    boolean_t init)
{
    vmxnet3_rxpool_t *rxPool = &dp->rxPool;
    boolean_t returned = B_FALSE;

    mutex_enter(&dp->rxPoolLock);
    ASSERT(rxPool->nBufs <= rxPool->nBufsLimit);
    if ((dp->devEnabled || init) && rxPool->nBufs < rxPool->nBufsLimit) {
        ASSERT((rxPool->listHead == NULL && rxPool->nBufs == 0) ||
            (rxPool->listHead != NULL && rxPool->nBufs != 0));
        rxBuf->next = rxPool->listHead;
        rxPool->listHead = rxBuf;
        rxPool->nBufs++;
        returned = B_TRUE;
    }
    mutex_exit(&dp->rxPoolLock);
    return (returned);
}

/*
 * Return a rxBuf to the pool or free it.
 */
static void
vmxnet3_put_rxbuf(vmxnet3_rxbuf_t *rxBuf)
{
    vmxnet3_softc_t *dp = rxBuf->dp;

    if (!vmxnet3_put_rxpool_buf(dp, rxBuf, B_FALSE))
        vmxnet3_free_rxbuf(dp, rxBuf);
}

/*
 * Get an unused rxBuf from the pool.
 *
 * Returns:
 *  A rxBuf or NULL if there are no buffers in the pool.
 */
static vmxnet3_rxbuf_t *
vmxnet3_get_rxpool_buf(vmxnet3_softc_t *dp)
{
    vmxnet3_rxpool_t *rxPool = &dp->rxPool;
    vmxnet3_rxbuf_t *rxBuf = NULL;

    mutex_enter(&dp->rxPoolLock);
    if (rxPool->listHead != NULL) {
        rxBuf = rxPool->listHead;
        rxPool->listHead = rxBuf->next;
        rxPool->nBufs--;
        ASSERT((rxPool->listHead == NULL && rxPool->nBufs == 0) ||
            (rxPool->listHead != NULL && rxPool->nBufs != 0));
    }
    mutex_exit(&dp->rxPoolLock);
    return (rxBuf);
}

/*
 * Fill a rxPool by allocating the maximum number of buffers.
 *
 * Returns:
 *  0 on success, non-zero on failure.
 */
static int
vmxnet3_rxpool_init(vmxnet3_softc_t *dp)
{
    int err = 0;
    vmxnet3_rxbuf_t *rxBuf;

    ASSERT(dp->rxPool.nBufsLimit > 0);
    while (dp->rxPool.nBufs < dp->rxPool.nBufsLimit) {
        if ((rxBuf = vmxnet3_alloc_rxbuf(dp, B_FALSE)) == NULL) {
            err = ENOMEM;
            break;
        }
        VERIFY(vmxnet3_put_rxpool_buf(dp, rxBuf, B_TRUE));
    }

    if (err != 0) {
        while ((rxBuf = vmxnet3_get_rxpool_buf(dp)) != NULL) {
            vmxnet3_free_rxbuf(dp, rxBuf);
        }
    }

    return (err);
}

/*
 * Populate a Rx descriptor with a new rxBuf. If the pool argument is B_TRUE,
 * then try to take a buffer from rxPool. If the pool is empty and the
 * dp->alloc_ok is true, then fall back to dynamic allocation. If pool is
 * B_FALSE, then always allocate a new buffer (this is only used when
 * populating the initial set of buffers in the receive queue during start).
 *
 * Returns:
 *  0 on success, non-zero on failure.
 */
static int
vmxnet3_rx_populate(vmxnet3_softc_t *dp, vmxnet3_rxqueue_t *rxq, uint16_t idx,
    boolean_t canSleep, boolean_t pool)
{
    vmxnet3_rxbuf_t *rxBuf = NULL;

    if (pool && (rxBuf = vmxnet3_get_rxpool_buf(dp)) == NULL) {
        /* The maximum number of pool buffers have been allocated. */
        atomic_inc_32(&dp->rx_pool_empty);
        if (!dp->alloc_ok) {
            atomic_inc_32(&dp->rx_alloc_failed);
        }
    }

    if (rxBuf == NULL && (!pool || dp->alloc_ok)) {
        rxBuf = vmxnet3_alloc_rxbuf(dp, canSleep);
    }

    if (rxBuf != NULL) {
        rxBuf->mblk = desballoc((uchar_t *)rxBuf->dma.buf,
            rxBuf->dma.bufLen, BPRI_MED, &rxBuf->freeCB);
        if (rxBuf->mblk == NULL) {
            if (pool) {
                VERIFY(vmxnet3_put_rxpool_buf(dp, rxBuf,
                    B_FALSE));
            } else {
                vmxnet3_free_rxbuf(dp, rxBuf);
            }
            atomic_inc_32(&dp->rx_alloc_failed);
            return (ENOMEM);
        }

        vmxnet3_cmdring_t *cmdRing = &rxq->cmdRing;
        Vmxnet3_GenericDesc *rxDesc = VMXNET3_GET_DESC(cmdRing, idx);

        rxq->bufRing[idx].rxBuf = rxBuf;
        rxDesc->rxd.addr = rxBuf->dma.bufPA;
        rxDesc->rxd.len = rxBuf->dma.bufLen;
        /* rxDesc->rxd.btype = 0; */
        membar_producer();
        rxDesc->rxd.gen = cmdRing->gen;
    } else {
        return (ENOMEM);
    }

    return (0);
}

/*
 * Initialize a RxQueue by populating the whole Rx ring with rxBufs.
 *
 * Returns:
 *  0 on success, non-zero on failure.
 */
int
vmxnet3_rxqueue_init(vmxnet3_softc_t *dp, vmxnet3_rxqueue_t *rxq)
{
    vmxnet3_cmdring_t *cmdRing = &rxq->cmdRing;
    int err;

    dp->rxPool.nBufsLimit = vmxnet3_getprop(dp, "RxBufPoolLimit", 0,
        cmdRing->size * 10, cmdRing->size * 2);

    do {
        if ((err = vmxnet3_rx_populate(dp, rxq, cmdRing->next2fill,
            B_TRUE, B_FALSE)) != 0) {
            goto error;
        }
        VMXNET3_INC_RING_IDX(cmdRing, cmdRing->next2fill);
    } while (cmdRing->next2fill);

    /*
     * Pre-allocate rxPool buffers so that we never have to allocate
     * new buffers from interrupt context when we need to replace a buffer
     * in the rxqueue.
     */
    if ((err = vmxnet3_rxpool_init(dp)) != 0) {
        goto error;
    }

    return (0);

error:
    while (cmdRing->next2fill) {
        VMXNET3_DEC_RING_IDX(cmdRing, cmdRing->next2fill);
        vmxnet3_free_rxbuf(dp, rxq->bufRing[cmdRing->next2fill].rxBuf);
    }

    return (err);
}

/*
 * Finish a RxQueue by freeing all the related rxBufs.
 */
void
vmxnet3_rxqueue_fini(vmxnet3_softc_t *dp, vmxnet3_rxqueue_t *rxq)
{
    vmxnet3_rxbuf_t *rxBuf;
    unsigned int i;

    ASSERT(!dp->devEnabled);

    /* First the rxPool */
    while ((rxBuf = vmxnet3_get_rxpool_buf(dp)))
        vmxnet3_free_rxbuf(dp, rxBuf);

    /* Then the ring */
    for (i = 0; i < rxq->cmdRing.size; i++) {
        rxBuf = rxq->bufRing[i].rxBuf;
        ASSERT(rxBuf);
        ASSERT(rxBuf->mblk);
        /*
         * Here, freemsg() will trigger a call to vmxnet3_put_rxbuf()
         * which will then call vmxnet3_free_rxbuf() because the
         * underlying device is disabled.
         */
        freemsg(rxBuf->mblk);
    }
}

/*
 * Determine if a received packet was checksummed by the Vmxnet3
 * device and tag the mp appropriately.
 */
static void
vmxnet3_rx_hwcksum(vmxnet3_softc_t *dp, mblk_t *mp,
    Vmxnet3_GenericDesc *compDesc)
{
    uint32_t flags = 0;

    if (!compDesc->rcd.cnc) {
        if (compDesc->rcd.v4 && compDesc->rcd.ipc) {
            flags |= HCK_IPV4_HDRCKSUM;
            if ((compDesc->rcd.tcp || compDesc->rcd.udp) &&
                compDesc->rcd.tuc) {
                flags |= HCK_FULLCKSUM | HCK_FULLCKSUM_OK;
            }
        }

        VMXNET3_DEBUG(dp, 3, "rx cksum flags = 0x%x\n", flags);

        (void) hcksum_assoc(mp, NULL, NULL, 0, 0, 0, 0, flags, 0);
    }
}

/*
 * Interrupt handler for Rx. Look if there are any pending Rx and
 * put them in mplist.
 *
 * Returns:
 *  A list of messages to pass to the MAC subystem.
 */
mblk_t *
vmxnet3_rx_intr(vmxnet3_softc_t *dp, vmxnet3_rxqueue_t *rxq)
{
    vmxnet3_compring_t *compRing = &rxq->compRing;
    vmxnet3_cmdring_t *cmdRing = &rxq->cmdRing;
    Vmxnet3_RxQueueCtrl *rxqCtrl = rxq->sharedCtrl;
    Vmxnet3_GenericDesc *compDesc;
    mblk_t *mplist = NULL, **mplistTail = &mplist;

    ASSERT(mutex_owned(&dp->intrLock));

    compDesc = VMXNET3_GET_DESC(compRing, compRing->next2comp);
    while (compDesc->rcd.gen == compRing->gen) {
        mblk_t *mp = NULL, **mpTail = &mp;
        boolean_t mpValid = B_TRUE;
        boolean_t eop;

        ASSERT(compDesc->rcd.sop);

        do {
            uint16_t rxdIdx = compDesc->rcd.rxdIdx;
            vmxnet3_rxbuf_t *rxBuf = rxq->bufRing[rxdIdx].rxBuf;
            mblk_t *mblk = rxBuf->mblk;
            Vmxnet3_GenericDesc *rxDesc;

            while (compDesc->rcd.gen != compRing->gen) {
                /*
                 * H/W may be still be in the middle of
                 * generating this entry, so hold on until
                 * the gen bit is flipped.
                 */
                membar_consumer();
            }
            ASSERT(compDesc->rcd.gen == compRing->gen);
            ASSERT(rxBuf);
            ASSERT(mblk);

            /* Some Rx descriptors may have been skipped */
            while (cmdRing->next2fill != rxdIdx) {
                rxDesc = VMXNET3_GET_DESC(cmdRing,
                    cmdRing->next2fill);
                rxDesc->rxd.gen = cmdRing->gen;
                VMXNET3_INC_RING_IDX(cmdRing,
                    cmdRing->next2fill);
            }

            eop = compDesc->rcd.eop;

            /*
             * Now we have a piece of the packet in the rxdIdx
             * descriptor. Grab it only if we achieve to replace
             * it with a fresh buffer.
             */
            if (vmxnet3_rx_populate(dp, rxq, rxdIdx, B_FALSE,
                B_TRUE) == 0) {
                /* Success, we can chain the mblk with the mp */
                mblk->b_wptr = mblk->b_rptr + compDesc->rcd.len;
                *mpTail = mblk;
                mpTail = &mblk->b_cont;
                ASSERT(*mpTail == NULL);

                VMXNET3_DEBUG(dp, 3, "rx 0x%p on [%u]\n", mblk,
                    rxdIdx);

                if (eop) {
                    if (!compDesc->rcd.err) {
                        /*
                         * Tag the mp if it was
                         * checksummed by the H/W
                         */
                        vmxnet3_rx_hwcksum(dp, mp,
                            compDesc);
                    } else {
                        mpValid = B_FALSE;
                    }
                }
            } else {
                /*
                 * Keep the same buffer, we still need
                 * to flip the gen bit
                 */
                rxDesc = VMXNET3_GET_DESC(cmdRing, rxdIdx);
                rxDesc->rxd.gen = cmdRing->gen;
                mpValid = B_FALSE;
            }

            VMXNET3_INC_RING_IDX(compRing, compRing->next2comp);
            VMXNET3_INC_RING_IDX(cmdRing, cmdRing->next2fill);
            compDesc = VMXNET3_GET_DESC(compRing,
                compRing->next2comp);
        } while (!eop);

        if (mp) {
            if (mpValid) {
                *mplistTail = mp;
                mplistTail = &mp->b_next;
                ASSERT(*mplistTail == NULL);
            } else {
                /* This message got holes, drop it */
                freemsg(mp);
            }
        }
    }

    if (rxqCtrl->updateRxProd) {
        uint32_t rxprod;

        /*
         * All buffers are actually available, but we can't tell that to
         * the device because it may interpret that as an empty ring.
         * So skip one buffer.
         */
        if (cmdRing->next2fill) {
            rxprod = cmdRing->next2fill - 1;
        } else {
            rxprod = cmdRing->size - 1;
        }
        VMXNET3_BAR0_PUT32(dp, VMXNET3_REG_RXPROD, rxprod);
    }

    return (mplist);
}