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qemu-e2k/dma-helpers.c

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/*
* 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/dma.h"
#include "trace.h"
#include "qemu/range.h"
#include "qemu/thread.h"
/* #define DEBUG_IOMMU */
static void do_dma_memory_set(AddressSpace *as,
dma_addr_t addr, uint8_t c, dma_addr_t len)
{
#define FILLBUF_SIZE 512
uint8_t fillbuf[FILLBUF_SIZE];
int l;
memset(fillbuf, c, FILLBUF_SIZE);
while (len > 0) {
l = len < FILLBUF_SIZE ? len : FILLBUF_SIZE;
address_space_rw(as, addr, fillbuf, l, true);
len -= l;
addr += l;
}
}
int dma_memory_set(DMAContext *dma, dma_addr_t addr, uint8_t c, dma_addr_t len)
{
dma_barrier(dma, DMA_DIRECTION_FROM_DEVICE);
if (dma_has_iommu(dma)) {
return iommu_dma_memory_set(dma, addr, c, len);
}
do_dma_memory_set(dma->as, addr, c, len);
return 0;
}
void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint, DMAContext *dma)
{
qsg->sg = g_malloc(alloc_hint * sizeof(ScatterGatherEntry));
qsg->nsg = 0;
qsg->nalloc = alloc_hint;
qsg->size = 0;
qsg->dma = dma;
}
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)
{
g_free(qsg->sg);
memset(qsg, 0, sizeof(*qsg));
}
typedef struct {
BlockDriverAIOCB common;
BlockDriverState *bs;
BlockDriverAIOCB *acb;
QEMUSGList *sg;
uint64_t sector_num;
DMADirection dir;
bool in_cancel;
int sg_cur_index;
dma_addr_t sg_cur_byte;
QEMUIOVector iov;
QEMUBH *bh;
DMAIOFunc *io_func;
} 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(dbs, 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) {
dma_memory_unmap(dbs->sg->dma, 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_bdrv_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;
}
if (!dbs->in_cancel) {
/* Requests may complete while dma_aio_cancel is in progress. In
* this case, the AIOCB should not be released because it is still
* referenced by dma_aio_cancel. */
qemu_aio_release(dbs);
}
}
static void dma_bdrv_cb(void *opaque, int ret)
{
DMAAIOCB *dbs = (DMAAIOCB *)opaque;
dma_addr_t cur_addr, cur_len;
void *mem;
trace_dma_bdrv_cb(dbs, ret);
dbs->acb = NULL;
dbs->sector_num += dbs->iov.size / 512;
dma_bdrv_unmap(dbs);
if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {
dma_complete(dbs, ret);
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 = dma_memory_map(dbs->sg->dma, 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);
cpu_register_map_client(dbs, continue_after_map_failure);
return;
}
dbs->acb = dbs->io_func(dbs->bs, dbs->sector_num, &dbs->iov,
dbs->iov.size / 512, dma_bdrv_cb, dbs);
assert(dbs->acb);
}
static void dma_aio_cancel(BlockDriverAIOCB *acb)
{
DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);
trace_dma_aio_cancel(dbs);
if (dbs->acb) {
BlockDriverAIOCB *acb = dbs->acb;
dbs->acb = NULL;
dbs->in_cancel = true;
bdrv_aio_cancel(acb);
dbs->in_cancel = false;
}
dbs->common.cb = NULL;
dma_complete(dbs, 0);
}
static const AIOCBInfo dma_aiocb_info = {
.aiocb_size = sizeof(DMAAIOCB),
.cancel = dma_aio_cancel,
};
BlockDriverAIOCB *dma_bdrv_io(
BlockDriverState *bs, QEMUSGList *sg, uint64_t sector_num,
DMAIOFunc *io_func, BlockDriverCompletionFunc *cb,
void *opaque, DMADirection dir)
{
DMAAIOCB *dbs = qemu_aio_get(&dma_aiocb_info, bs, cb, opaque);
trace_dma_bdrv_io(dbs, bs, sector_num, (dir == DMA_DIRECTION_TO_DEVICE));
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->dir = dir;
dbs->io_func = io_func;
dbs->bh = NULL;
qemu_iovec_init(&dbs->iov, sg->nsg);
dma_bdrv_cb(dbs, 0);
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, bdrv_aio_readv, cb, opaque,
DMA_DIRECTION_FROM_DEVICE);
}
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, bdrv_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->dma, 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(BlockDriverState *bs, BlockAcctCookie *cookie,
QEMUSGList *sg, enum BlockAcctType type)
{
bdrv_acct_start(bs, cookie, sg->size, type);
}
bool iommu_dma_memory_valid(DMAContext *dma, dma_addr_t addr, dma_addr_t len,
DMADirection dir)
{
hwaddr paddr, plen;
#ifdef DEBUG_IOMMU
fprintf(stderr, "dma_memory_check context=%p addr=0x" DMA_ADDR_FMT
" len=0x" DMA_ADDR_FMT " dir=%d\n", dma, addr, len, dir);
#endif
while (len) {
if (dma->translate(dma, addr, &paddr, &plen, dir) != 0) {
return false;
}
/* The translation might be valid for larger regions. */
if (plen > len) {
plen = len;
}
if (!address_space_access_valid(dma->as, paddr, len,
dir == DMA_DIRECTION_FROM_DEVICE)) {
return false;
}
len -= plen;
addr += plen;
}
return true;
}
int iommu_dma_memory_rw(DMAContext *dma, dma_addr_t addr,
void *buf, dma_addr_t len, DMADirection dir)
{
hwaddr paddr, plen;
int err;
#ifdef DEBUG_IOMMU
fprintf(stderr, "dma_memory_rw context=%p addr=0x" DMA_ADDR_FMT " len=0x"
DMA_ADDR_FMT " dir=%d\n", dma, addr, len, dir);
#endif
while (len) {
err = dma->translate(dma, addr, &paddr, &plen, dir);
if (err) {
/*
* In case of failure on reads from the guest, we clean the
* destination buffer so that a device that doesn't test
* for errors will not expose qemu internal memory.
*/
memset(buf, 0, len);
return -1;
}
/* The translation might be valid for larger regions. */
if (plen > len) {
plen = len;
}
address_space_rw(dma->as, paddr, buf, plen, dir == DMA_DIRECTION_FROM_DEVICE);
len -= plen;
addr += plen;
buf += plen;
}
return 0;
}
int iommu_dma_memory_set(DMAContext *dma, dma_addr_t addr, uint8_t c,
dma_addr_t len)
{
hwaddr paddr, plen;
int err;
#ifdef DEBUG_IOMMU
fprintf(stderr, "dma_memory_set context=%p addr=0x" DMA_ADDR_FMT
" len=0x" DMA_ADDR_FMT "\n", dma, addr, len);
#endif
while (len) {
err = dma->translate(dma, addr, &paddr, &plen,
DMA_DIRECTION_FROM_DEVICE);
if (err) {
return err;
}
/* The translation might be valid for larger regions. */
if (plen > len) {
plen = len;
}
do_dma_memory_set(dma->as, paddr, c, plen);
len -= plen;
addr += plen;
}
return 0;
}
void dma_context_init(DMAContext *dma, AddressSpace *as, DMATranslateFunc translate,
DMAMapFunc map, DMAUnmapFunc unmap)
{
#ifdef DEBUG_IOMMU
fprintf(stderr, "dma_context_init(%p, %p, %p, %p)\n",
dma, translate, map, unmap);
#endif
dma->as = as;
dma->translate = translate;
dma->map = map;
dma->unmap = unmap;
}
void *iommu_dma_memory_map(DMAContext *dma, dma_addr_t addr, dma_addr_t *len,
DMADirection dir)
{
int err;
hwaddr paddr, plen;
void *buf;
if (dma->map) {
return dma->map(dma, addr, len, dir);
}
plen = *len;
err = dma->translate(dma, addr, &paddr, &plen, dir);
if (err) {
return NULL;
}
/*
* If this is true, the virtual region is contiguous,
* but the translated physical region isn't. We just
* clamp *len, much like address_space_map() does.
*/
if (plen < *len) {
*len = plen;
}
buf = address_space_map(dma->as, paddr, &plen, dir == DMA_DIRECTION_FROM_DEVICE);
*len = plen;
return buf;
}
void iommu_dma_memory_unmap(DMAContext *dma, void *buffer, dma_addr_t len,
DMADirection dir, dma_addr_t access_len)
{
if (dma->unmap) {
dma->unmap(dma, buffer, len, dir, access_len);
return;
}
address_space_unmap(dma->as, buffer, len, dir == DMA_DIRECTION_FROM_DEVICE,
access_len);
}
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