qemu/dma-helpers.c
Paolo Bonzini 8a8e63ebdd dma-helpers: change BlockBackend to opaque value in DMAIOFunc
Callers of dma_blk_io have no way to pass extra data to the DMAIOFunc,
because the original callback and opaque are gone by the time DMAIOFunc
is called.  On the other hand, the BlockBackend is usually derived
from those extra data that you could pass to the DMAIOFunc (in the
next patch, that would be the SCSIRequest).

So change DMAIOFunc's prototype, decoupling it from blk_aio_readv
and blk_aio_writev's.  The new prototype loses the BlockBackend
and gains an extra opaque value which, in the case of dma_blk_readv
and dma_blk_writev, is of course used for the BlockBackend.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-05-25 19:04:11 +02:00

293 lines
7.5 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 "qemu/osdep.h"
#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;
AioContext *ctx;
BlockAIOCB *acb;
QEMUSGList *sg;
uint64_t offset;
DMADirection dir;
int sg_cur_index;
dma_addr_t sg_cur_byte;
QEMUIOVector iov;
QEMUBH *bh;
DMAIOFunc *io_func;
void *io_func_opaque;
} 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->offset += dbs->iov.size;
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(dbs->ctx, 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->offset, &dbs->iov,
dma_blk_cb, dbs, dbs->io_func_opaque);
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(AioContext *ctx,
QEMUSGList *sg, uint64_t offset,
DMAIOFunc *io_func, void *io_func_opaque,
BlockCompletionFunc *cb,
void *opaque, DMADirection dir)
{
DMAAIOCB *dbs = qemu_aio_get(&dma_aiocb_info, NULL, cb, opaque);
trace_dma_blk_io(dbs, io_func_opaque, offset, (dir == DMA_DIRECTION_TO_DEVICE));
dbs->acb = NULL;
dbs->sg = sg;
dbs->ctx = ctx;
dbs->offset = offset;
dbs->sg_cur_index = 0;
dbs->sg_cur_byte = 0;
dbs->dir = dir;
dbs->io_func = io_func;
dbs->io_func_opaque = io_func_opaque;
dbs->bh = NULL;
qemu_iovec_init(&dbs->iov, sg->nsg);
dma_blk_cb(dbs, 0);
return &dbs->common;
}
static
BlockAIOCB *dma_blk_read_io_func(int64_t offset, QEMUIOVector *iov,
BlockCompletionFunc *cb, void *cb_opaque,
void *opaque)
{
BlockBackend *blk = opaque;
return blk_aio_preadv(blk, offset, iov, 0, cb, cb_opaque);
}
BlockAIOCB *dma_blk_read(BlockBackend *blk,
QEMUSGList *sg, uint64_t offset,
void (*cb)(void *opaque, int ret), void *opaque)
{
return dma_blk_io(blk_get_aio_context(blk),
sg, offset, dma_blk_read_io_func, blk, cb, opaque,
DMA_DIRECTION_FROM_DEVICE);
}
static
BlockAIOCB *dma_blk_write_io_func(int64_t offset, QEMUIOVector *iov,
BlockCompletionFunc *cb, void *cb_opaque,
void *opaque)
{
BlockBackend *blk = opaque;
return blk_aio_pwritev(blk, offset, iov, 0, cb, cb_opaque);
}
BlockAIOCB *dma_blk_write(BlockBackend *blk,
QEMUSGList *sg, uint64_t offset,
void (*cb)(void *opaque, int ret), void *opaque)
{
return dma_blk_io(blk_get_aio_context(blk),
sg, offset, dma_blk_write_io_func, blk, 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);
}