From 59a703ebaa9cb5aeda986dc8f627b8d23e3297cd Mon Sep 17 00:00:00 2001 From: aliguori Date: Thu, 5 Feb 2009 21:23:58 +0000 Subject: [PATCH] Introduce block dma helpers (Avi Kivity) These helpers perform read/write requests on entire scatter/gather lists, relieving the device emulation code from mapping and unmapping physical memory, and from looping when map resources are exhausted. Signed-off-by: Avi Kivity Signed-off-by: Anthony Liguori git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6524 c046a42c-6fe2-441c-8c8c-71466251a162 --- dma-helpers.c | 119 +++++++++++++++++++++++++++++++++++++++++++++++++- dma.h | 8 ++++ 2 files changed, 126 insertions(+), 1 deletion(-) diff --git a/dma-helpers.c b/dma-helpers.c index 11ad3a4344..b2ade19acb 100644 --- a/dma-helpers.c +++ b/dma-helpers.c @@ -8,7 +8,7 @@ */ #include "dma.h" - +#include "block_int.h" void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint) { @@ -36,3 +36,120 @@ void qemu_sglist_destroy(QEMUSGList *qsg) qemu_free(qsg->sg); } +typedef struct { + 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; +} DMABlockState; + +static void dma_bdrv_cb(void *opaque, int ret); + +static void reschedule_dma(void *opaque) +{ + DMABlockState *dbs = (DMABlockState *)opaque; + + qemu_bh_delete(dbs->bh); + dbs->bh = NULL; + dma_bdrv_cb(opaque, 0); +} + +static void continue_after_map_failure(void *opaque) +{ + DMABlockState *dbs = (DMABlockState *)opaque; + + dbs->bh = qemu_bh_new(reschedule_dma, dbs); + qemu_bh_schedule(dbs->bh); +} + +static void dma_bdrv_cb(void *opaque, int ret) +{ + DMABlockState *dbs = (DMABlockState *)opaque; + target_phys_addr_t cur_addr, cur_len; + void *mem; + int i; + + dbs->sector_num += dbs->iov.size / 512; + 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); + } + qemu_iovec_reset(&dbs->iov); + + if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) { + dbs->acb->cb(dbs->acb->opaque, ret); + qemu_iovec_destroy(&dbs->iov); + qemu_aio_release(dbs->acb); + qemu_free(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) { + bdrv_aio_writev(dbs->bs, dbs->sector_num, &dbs->iov, + dbs->iov.size / 512, dma_bdrv_cb, dbs); + } else { + bdrv_aio_readv(dbs->bs, dbs->sector_num, &dbs->iov, + dbs->iov.size / 512, dma_bdrv_cb, dbs); + } +} + +static BlockDriverAIOCB *dma_bdrv_io( + BlockDriverState *bs, QEMUSGList *sg, uint64_t sector_num, + BlockDriverCompletionFunc *cb, void *opaque, + int is_write) +{ + DMABlockState *dbs = qemu_malloc(sizeof(*dbs)); + + dbs->bs = bs; + dbs->acb = qemu_aio_get(bs, cb, opaque); + 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); + return dbs->acb; +} + + +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); +} + diff --git a/dma.h b/dma.h index 16af50f1f7..d596717f14 100644 --- a/dma.h +++ b/dma.h @@ -12,6 +12,7 @@ #include #include "cpu.h" +#include "block.h" typedef struct { target_phys_addr_t base; @@ -30,4 +31,11 @@ void qemu_sglist_add(QEMUSGList *qsg, target_phys_addr_t base, target_phys_addr_t len); void qemu_sglist_destroy(QEMUSGList *qsg); +BlockDriverAIOCB *dma_bdrv_read(BlockDriverState *bs, + QEMUSGList *sg, uint64_t sector, + BlockDriverCompletionFunc *cb, void *opaque); +BlockDriverAIOCB *dma_bdrv_write(BlockDriverState *bs, + QEMUSGList *sg, uint64_t sector, + BlockDriverCompletionFunc *cb, void *opaque); + #endif