root / dma-helpers.c @ a15fdf86
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/*
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* DMA helper functions
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*
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* Copyright (c) 2009 Red Hat
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*
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* This work is licensed under the terms of the GNU General Public License
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* (GNU GPL), version 2 or later.
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*/
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#include "dma.h" |
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#include "block_int.h" |
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void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint) |
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{ |
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qsg->sg = qemu_malloc(alloc_hint * sizeof(ScatterGatherEntry));
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qsg->nsg = 0;
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qsg->nalloc = alloc_hint; |
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qsg->size = 0;
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} |
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void qemu_sglist_add(QEMUSGList *qsg, target_phys_addr_t base,
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target_phys_addr_t len) |
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{ |
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if (qsg->nsg == qsg->nalloc) {
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qsg->nalloc = 2 * qsg->nalloc + 1; |
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qsg->sg = qemu_realloc(qsg->sg, qsg->nalloc * sizeof(ScatterGatherEntry));
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} |
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qsg->sg[qsg->nsg].base = base; |
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qsg->sg[qsg->nsg].len = len; |
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qsg->size += len; |
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++qsg->nsg; |
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} |
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void qemu_sglist_destroy(QEMUSGList *qsg)
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{ |
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qemu_free(qsg->sg); |
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} |
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typedef struct { |
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BlockDriverAIOCB common; |
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BlockDriverState *bs; |
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BlockDriverAIOCB *acb; |
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QEMUSGList *sg; |
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uint64_t sector_num; |
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int is_write;
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int sg_cur_index;
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target_phys_addr_t sg_cur_byte; |
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QEMUIOVector iov; |
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QEMUBH *bh; |
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} DMAAIOCB; |
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static void dma_bdrv_cb(void *opaque, int ret); |
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static void reschedule_dma(void *opaque) |
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{ |
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DMAAIOCB *dbs = (DMAAIOCB *)opaque; |
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qemu_bh_delete(dbs->bh); |
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dbs->bh = NULL;
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dma_bdrv_cb(opaque, 0);
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} |
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static void continue_after_map_failure(void *opaque) |
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{ |
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DMAAIOCB *dbs = (DMAAIOCB *)opaque; |
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dbs->bh = qemu_bh_new(reschedule_dma, dbs); |
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qemu_bh_schedule(dbs->bh); |
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} |
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static void dma_bdrv_unmap(DMAAIOCB *dbs) |
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{ |
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int i;
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for (i = 0; i < dbs->iov.niov; ++i) { |
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cpu_physical_memory_unmap(dbs->iov.iov[i].iov_base, |
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dbs->iov.iov[i].iov_len, !dbs->is_write, |
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dbs->iov.iov[i].iov_len); |
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} |
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} |
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static void dma_bdrv_cb(void *opaque, int ret) |
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{ |
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DMAAIOCB *dbs = (DMAAIOCB *)opaque; |
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target_phys_addr_t cur_addr, cur_len; |
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void *mem;
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dbs->acb = NULL;
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dbs->sector_num += dbs->iov.size / 512;
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dma_bdrv_unmap(dbs); |
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qemu_iovec_reset(&dbs->iov); |
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if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) { |
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dbs->common.cb(dbs->common.opaque, ret); |
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qemu_iovec_destroy(&dbs->iov); |
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qemu_aio_release(dbs); |
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return;
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} |
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while (dbs->sg_cur_index < dbs->sg->nsg) {
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cur_addr = dbs->sg->sg[dbs->sg_cur_index].base + dbs->sg_cur_byte; |
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cur_len = dbs->sg->sg[dbs->sg_cur_index].len - dbs->sg_cur_byte; |
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mem = cpu_physical_memory_map(cur_addr, &cur_len, !dbs->is_write); |
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if (!mem)
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break;
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qemu_iovec_add(&dbs->iov, mem, cur_len); |
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dbs->sg_cur_byte += cur_len; |
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if (dbs->sg_cur_byte == dbs->sg->sg[dbs->sg_cur_index].len) {
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dbs->sg_cur_byte = 0;
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++dbs->sg_cur_index; |
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} |
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} |
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if (dbs->iov.size == 0) { |
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cpu_register_map_client(dbs, continue_after_map_failure); |
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return;
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} |
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if (dbs->is_write) {
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dbs->acb = bdrv_aio_writev(dbs->bs, dbs->sector_num, &dbs->iov, |
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dbs->iov.size / 512, dma_bdrv_cb, dbs);
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} else {
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dbs->acb = bdrv_aio_readv(dbs->bs, dbs->sector_num, &dbs->iov, |
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dbs->iov.size / 512, dma_bdrv_cb, dbs);
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} |
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if (!dbs->acb) {
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dma_bdrv_unmap(dbs); |
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qemu_iovec_destroy(&dbs->iov); |
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return;
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} |
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} |
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static void dma_aio_cancel(BlockDriverAIOCB *acb) |
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{ |
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DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common); |
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if (dbs->acb) {
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bdrv_aio_cancel(dbs->acb); |
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} |
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} |
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static AIOPool dma_aio_pool = {
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.aiocb_size = sizeof(DMAAIOCB),
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.cancel = dma_aio_cancel, |
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}; |
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static BlockDriverAIOCB *dma_bdrv_io(
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BlockDriverState *bs, QEMUSGList *sg, uint64_t sector_num, |
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BlockDriverCompletionFunc *cb, void *opaque,
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int is_write)
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{ |
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DMAAIOCB *dbs = qemu_aio_get(&dma_aio_pool, bs, cb, opaque); |
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dbs->acb = NULL;
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dbs->bs = bs; |
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dbs->sg = sg; |
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dbs->sector_num = sector_num; |
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dbs->sg_cur_index = 0;
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dbs->sg_cur_byte = 0;
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dbs->is_write = is_write; |
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dbs->bh = NULL;
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qemu_iovec_init(&dbs->iov, sg->nsg); |
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dma_bdrv_cb(dbs, 0);
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if (!dbs->acb) {
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qemu_aio_release(dbs); |
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return NULL; |
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} |
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return &dbs->common;
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} |
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BlockDriverAIOCB *dma_bdrv_read(BlockDriverState *bs, |
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QEMUSGList *sg, uint64_t sector, |
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void (*cb)(void *opaque, int ret), void *opaque) |
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{ |
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return dma_bdrv_io(bs, sg, sector, cb, opaque, 0); |
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} |
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BlockDriverAIOCB *dma_bdrv_write(BlockDriverState *bs, |
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QEMUSGList *sg, uint64_t sector, |
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void (*cb)(void *opaque, int ret), void *opaque) |
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{ |
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return dma_bdrv_io(bs, sg, sector, cb, opaque, 1); |
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} |