diff options
Diffstat (limited to 'dma-helpers.c')
| -rw-r--r-- | dma-helpers.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/dma-helpers.c b/dma-helpers.c new file mode 100644 index 0000000..712ed89 --- /dev/null +++ b/dma-helpers.c @@ -0,0 +1,184 @@ +/* + * DMA helper functions + * + * Copyright (c) 2009 Red Hat + * + * This work is licensed under the terms of the GNU General Public License + * (GNU GPL), version 2 or later. + */ + +#include "dma.h" +#include "block_int.h" + +void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint) +{ + qsg->sg = qemu_malloc(alloc_hint * sizeof(ScatterGatherEntry)); + qsg->nsg = 0; + qsg->nalloc = alloc_hint; + qsg->size = 0; +} + +void qemu_sglist_add(QEMUSGList *qsg, target_phys_addr_t base, + target_phys_addr_t len) +{ + if (qsg->nsg == qsg->nalloc) { + qsg->nalloc = 2 * qsg->nalloc + 1; + qsg->sg = qemu_realloc(qsg->sg, qsg->nalloc * sizeof(ScatterGatherEntry)); + } + qsg->sg[qsg->nsg].base = base; + qsg->sg[qsg->nsg].len = len; + qsg->size += len; + ++qsg->nsg; +} + +void qemu_sglist_destroy(QEMUSGList *qsg) +{ + qemu_free(qsg->sg); +} + +typedef struct { + BlockDriverAIOCB common; + BlockDriverState *bs; + BlockDriverAIOCB *acb; + QEMUSGList *sg; + uint64_t sector_num; + int is_write; + int sg_cur_index; + target_phys_addr_t sg_cur_byte; + QEMUIOVector iov; + QEMUBH *bh; +} DMAAIOCB; + +static void dma_bdrv_cb(void *opaque, int ret); + +static void reschedule_dma(void *opaque) +{ + DMAAIOCB *dbs = (DMAAIOCB *)opaque; + + qemu_bh_delete(dbs->bh); + dbs->bh = NULL; + dma_bdrv_cb(opaque, 0); +} + +static void continue_after_map_failure(void *opaque) +{ + DMAAIOCB *dbs = (DMAAIOCB *)opaque; + + dbs->bh = qemu_bh_new(reschedule_dma, dbs); + qemu_bh_schedule(dbs->bh); +} + +static void dma_bdrv_unmap(DMAAIOCB *dbs) +{ + int i; + + for (i = 0; i < dbs->iov.niov; ++i) { + cpu_physical_memory_unmap(dbs->iov.iov[i].iov_base, + dbs->iov.iov[i].iov_len, !dbs->is_write, + dbs->iov.iov[i].iov_len); + } +} + +static void dma_bdrv_cb(void *opaque, int ret) +{ + DMAAIOCB *dbs = (DMAAIOCB *)opaque; + target_phys_addr_t cur_addr, cur_len; + void *mem; + + dbs->acb = NULL; + dbs->sector_num += dbs->iov.size / 512; + dma_bdrv_unmap(dbs); + qemu_iovec_reset(&dbs->iov); + + if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) { + dbs->common.cb(dbs->common.opaque, ret); + qemu_iovec_destroy(&dbs->iov); + qemu_aio_release(dbs); + return; + } + + while (dbs->sg_cur_index < dbs->sg->nsg) { + cur_addr = dbs->sg->sg[dbs->sg_cur_index].base + dbs->sg_cur_byte; + cur_len = dbs->sg->sg[dbs->sg_cur_index].len - dbs->sg_cur_byte; + mem = cpu_physical_memory_map(cur_addr, &cur_len, !dbs->is_write); + if (!mem) + break; + qemu_iovec_add(&dbs->iov, mem, cur_len); + dbs->sg_cur_byte += cur_len; + if (dbs->sg_cur_byte == dbs->sg->sg[dbs->sg_cur_index].len) { + dbs->sg_cur_byte = 0; + ++dbs->sg_cur_index; + } + } + + if (dbs->iov.size == 0) { + cpu_register_map_client(dbs, continue_after_map_failure); + return; + } + + if (dbs->is_write) { + dbs->acb = bdrv_aio_writev(dbs->bs, dbs->sector_num, &dbs->iov, + dbs->iov.size / 512, dma_bdrv_cb, dbs); + } else { + dbs->acb = bdrv_aio_readv(dbs->bs, dbs->sector_num, &dbs->iov, + dbs->iov.size / 512, dma_bdrv_cb, dbs); + } + if (!dbs->acb) { + dma_bdrv_unmap(dbs); + qemu_iovec_destroy(&dbs->iov); + return; + } +} + +static void dma_aio_cancel(BlockDriverAIOCB *acb) +{ + DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common); + + if (dbs->acb) { + bdrv_aio_cancel(dbs->acb); + } +} + +static AIOPool dma_aio_pool = { + .aiocb_size = sizeof(DMAAIOCB), + .cancel = dma_aio_cancel, +}; + +static BlockDriverAIOCB *dma_bdrv_io( + BlockDriverState *bs, QEMUSGList *sg, uint64_t sector_num, + BlockDriverCompletionFunc *cb, void *opaque, + int is_write) +{ + DMAAIOCB *dbs = qemu_aio_get(&dma_aio_pool, bs, cb, opaque); + + dbs->acb = NULL; + dbs->bs = bs; + dbs->sg = sg; + dbs->sector_num = sector_num; + dbs->sg_cur_index = 0; + dbs->sg_cur_byte = 0; + dbs->is_write = is_write; + dbs->bh = NULL; + qemu_iovec_init(&dbs->iov, sg->nsg); + dma_bdrv_cb(dbs, 0); + if (!dbs->acb) { + qemu_aio_release(dbs); + return NULL; + } + return &dbs->common; +} + + +BlockDriverAIOCB *dma_bdrv_read(BlockDriverState *bs, + QEMUSGList *sg, uint64_t sector, + void (*cb)(void *opaque, int ret), void *opaque) +{ + return dma_bdrv_io(bs, sg, sector, cb, opaque, 0); +} + +BlockDriverAIOCB *dma_bdrv_write(BlockDriverState *bs, + QEMUSGList *sg, uint64_t sector, + void (*cb)(void *opaque, int ret), void *opaque) +{ + return dma_bdrv_io(bs, sg, sector, cb, opaque, 1); +} |