qemu/dma-helpers.c

270 lines
6.8 KiB
C

/*
* 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 "sysemu/block-backend.h"
#include "sysemu/dma.h"
#include "trace.h"
#include "qemu/thread.h"
#include "qemu/main-loop.h"
/* #define DEBUG_IOMMU */
int dma_memory_set(AddressSpace *as, dma_addr_t addr, uint8_t c, dma_addr_t len)
{
dma_barrier(as, DMA_DIRECTION_FROM_DEVICE);
#define FILLBUF_SIZE 512
uint8_t fillbuf[FILLBUF_SIZE];
int l;
bool error = false;
memset(fillbuf, c, FILLBUF_SIZE);
while (len > 0) {
l = len < FILLBUF_SIZE ? len : FILLBUF_SIZE;
error |= address_space_rw(as, addr, MEMTXATTRS_UNSPECIFIED,
fillbuf, l, true);
len -= l;
addr += l;
}
return error;
}
void qemu_sglist_init(QEMUSGList *qsg, DeviceState *dev, int alloc_hint,
AddressSpace *as)
{
qsg->sg = g_malloc(alloc_hint * sizeof(ScatterGatherEntry));
qsg->nsg = 0;
qsg->nalloc = alloc_hint;
qsg->size = 0;
qsg->as = as;
qsg->dev = dev;
object_ref(OBJECT(dev));
}
void qemu_sglist_add(QEMUSGList *qsg, dma_addr_t base, dma_addr_t len)
{
if (qsg->nsg == qsg->nalloc) {
qsg->nalloc = 2 * qsg->nalloc + 1;
qsg->sg = g_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)
{
object_unref(OBJECT(qsg->dev));
g_free(qsg->sg);
memset(qsg, 0, sizeof(*qsg));
}
typedef struct {
BlockAIOCB common;
BlockBackend *blk;
BlockAIOCB *acb;
QEMUSGList *sg;
uint64_t sector_num;
DMADirection dir;
int sg_cur_index;
dma_addr_t sg_cur_byte;
QEMUIOVector iov;
QEMUBH *bh;
DMAIOFunc *io_func;
} DMAAIOCB;
static void dma_blk_cb(void *opaque, int ret);
static void reschedule_dma(void *opaque)
{
DMAAIOCB *dbs = (DMAAIOCB *)opaque;
qemu_bh_delete(dbs->bh);
dbs->bh = NULL;
dma_blk_cb(dbs, 0);
}
static void dma_blk_unmap(DMAAIOCB *dbs)
{
int i;
for (i = 0; i < dbs->iov.niov; ++i) {
dma_memory_unmap(dbs->sg->as, dbs->iov.iov[i].iov_base,
dbs->iov.iov[i].iov_len, dbs->dir,
dbs->iov.iov[i].iov_len);
}
qemu_iovec_reset(&dbs->iov);
}
static void dma_complete(DMAAIOCB *dbs, int ret)
{
trace_dma_complete(dbs, ret, dbs->common.cb);
dma_blk_unmap(dbs);
if (dbs->common.cb) {
dbs->common.cb(dbs->common.opaque, ret);
}
qemu_iovec_destroy(&dbs->iov);
if (dbs->bh) {
qemu_bh_delete(dbs->bh);
dbs->bh = NULL;
}
qemu_aio_unref(dbs);
}
static void dma_blk_cb(void *opaque, int ret)
{
DMAAIOCB *dbs = (DMAAIOCB *)opaque;
dma_addr_t cur_addr, cur_len;
void *mem;
trace_dma_blk_cb(dbs, ret);
dbs->acb = NULL;
dbs->sector_num += dbs->iov.size / 512;
if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {
dma_complete(dbs, ret);
return;
}
dma_blk_unmap(dbs);
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 = dma_memory_map(dbs->sg->as, cur_addr, &cur_len, dbs->dir);
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) {
trace_dma_map_wait(dbs);
dbs->bh = aio_bh_new(blk_get_aio_context(dbs->blk),
reschedule_dma, dbs);
cpu_register_map_client(dbs->bh);
return;
}
if (dbs->iov.size & ~BDRV_SECTOR_MASK) {
qemu_iovec_discard_back(&dbs->iov, dbs->iov.size & ~BDRV_SECTOR_MASK);
}
dbs->acb = dbs->io_func(dbs->blk, dbs->sector_num, &dbs->iov,
dbs->iov.size / 512, dma_blk_cb, dbs);
assert(dbs->acb);
}
static void dma_aio_cancel(BlockAIOCB *acb)
{
DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);
trace_dma_aio_cancel(dbs);
if (dbs->acb) {
blk_aio_cancel_async(dbs->acb);
}
if (dbs->bh) {
cpu_unregister_map_client(dbs->bh);
qemu_bh_delete(dbs->bh);
dbs->bh = NULL;
}
}
static const AIOCBInfo dma_aiocb_info = {
.aiocb_size = sizeof(DMAAIOCB),
.cancel_async = dma_aio_cancel,
};
BlockAIOCB *dma_blk_io(
BlockBackend *blk, QEMUSGList *sg, uint64_t sector_num,
DMAIOFunc *io_func, BlockCompletionFunc *cb,
void *opaque, DMADirection dir)
{
DMAAIOCB *dbs = blk_aio_get(&dma_aiocb_info, blk, cb, opaque);
trace_dma_blk_io(dbs, blk, sector_num, (dir == DMA_DIRECTION_TO_DEVICE));
dbs->acb = NULL;
dbs->blk = blk;
dbs->sg = sg;
dbs->sector_num = sector_num;
dbs->sg_cur_index = 0;
dbs->sg_cur_byte = 0;
dbs->dir = dir;
dbs->io_func = io_func;
dbs->bh = NULL;
qemu_iovec_init(&dbs->iov, sg->nsg);
dma_blk_cb(dbs, 0);
return &dbs->common;
}
BlockAIOCB *dma_blk_read(BlockBackend *blk,
QEMUSGList *sg, uint64_t sector,
void (*cb)(void *opaque, int ret), void *opaque)
{
return dma_blk_io(blk, sg, sector, blk_aio_readv, cb, opaque,
DMA_DIRECTION_FROM_DEVICE);
}
BlockAIOCB *dma_blk_write(BlockBackend *blk,
QEMUSGList *sg, uint64_t sector,
void (*cb)(void *opaque, int ret), void *opaque)
{
return dma_blk_io(blk, sg, sector, blk_aio_writev, cb, opaque,
DMA_DIRECTION_TO_DEVICE);
}
static uint64_t dma_buf_rw(uint8_t *ptr, int32_t len, QEMUSGList *sg,
DMADirection dir)
{
uint64_t resid;
int sg_cur_index;
resid = sg->size;
sg_cur_index = 0;
len = MIN(len, resid);
while (len > 0) {
ScatterGatherEntry entry = sg->sg[sg_cur_index++];
int32_t xfer = MIN(len, entry.len);
dma_memory_rw(sg->as, entry.base, ptr, xfer, dir);
ptr += xfer;
len -= xfer;
resid -= xfer;
}
return resid;
}
uint64_t dma_buf_read(uint8_t *ptr, int32_t len, QEMUSGList *sg)
{
return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_FROM_DEVICE);
}
uint64_t dma_buf_write(uint8_t *ptr, int32_t len, QEMUSGList *sg)
{
return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_TO_DEVICE);
}
void dma_acct_start(BlockBackend *blk, BlockAcctCookie *cookie,
QEMUSGList *sg, enum BlockAcctType type)
{
block_acct_start(blk_get_stats(blk), cookie, sg->size, type);
}