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Convert IDE to directly access guest memory (Avi Kivity)

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Instead of copying to a temporary buffer, map guest memory for IDE DMA
transactions.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6398 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aliguori 2009-01-22 16:59:28 +00:00
parent 3b69e4b9ad
commit 7aea4412b6
1 changed files with 117 additions and 16 deletions
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133
hw/ide.c
View File

@ -422,6 +422,7 @@ typedef struct IDEState {
int atapi_dma; /* true if dma is requested for the packet cmd */
/* ATA DMA state */
int io_buffer_size;
QEMUIOVector iovec;
/* PIO transfer handling */
int req_nb_sectors; /* number of sectors per interrupt */
EndTransferFunc *end_transfer_func;
@ -862,6 +863,66 @@ static void ide_sector_read(IDEState *s)
}
}
/* return 0 if buffer completed */
static int dma_buf_prepare(BMDMAState *bm, int is_write)
{
IDEState *s = bm->ide_if;
struct {
uint32_t addr;
uint32_t size;
} prd;
int l, len;
void *mem;
target_phys_addr_t l1;
qemu_iovec_init(&s->iovec, s->nsector / (TARGET_PAGE_SIZE/512) + 1);
s->io_buffer_size = 0;
for(;;) {
if (bm->cur_prd_len == 0) {
/* end of table (with a fail safe of one page) */
if (bm->cur_prd_last ||
(bm->cur_addr - bm->addr) >= 4096)
return s->io_buffer_size != 0;
cpu_physical_memory_read(bm->cur_addr, (uint8_t *)&prd, 8);
bm->cur_addr += 8;
prd.addr = le32_to_cpu(prd.addr);
prd.size = le32_to_cpu(prd.size);
len = prd.size & 0xfffe;
if (len == 0)
len = 0x10000;
bm->cur_prd_len = len;
bm->cur_prd_addr = prd.addr;
bm->cur_prd_last = (prd.size & 0x80000000);
}
l = bm->cur_prd_len;
if (l > 0) {
l1 = l;
mem = cpu_physical_memory_map(bm->cur_prd_addr, &l1, is_write);
if (!mem) {
break;
}
qemu_iovec_add(&s->iovec, mem, l1);
bm->cur_prd_addr += l1;
bm->cur_prd_len -= l1;
s->io_buffer_size += l1;
}
}
return 1;
}
static void dma_buf_commit(IDEState *s, int is_write)
{
int i;
for (i = 0; i < s->iovec.niov; ++i) {
cpu_physical_memory_unmap(s->iovec.iov[i].iov_base,
s->iovec.iov[i].iov_len, is_write,
s->iovec.iov[i].iov_len);
}
qemu_iovec_destroy(&s->iovec);
}
static void ide_dma_error(IDEState *s)
{
ide_transfer_stop(s);
@ -883,10 +944,12 @@ static int ide_handle_write_error(IDEState *s, int error, int op)
s->bmdma->status |= op;
vm_stop(0);
} else {
if (op == BM_STATUS_DMA_RETRY)
if (op == BM_STATUS_DMA_RETRY) {
dma_buf_commit(s, 0);
ide_dma_error(s);
else
} else {
ide_rw_error(s);
}
}
return 1;
@ -940,6 +1003,39 @@ static int dma_buf_rw(BMDMAState *bm, int is_write)
return 1;
}
typedef struct {
BMDMAState *bm;
void (*cb)(void *opaque, int ret);
QEMUBH *bh;
} MapFailureContinuation;
static void reschedule_dma(void *opaque)
{
MapFailureContinuation *cont = opaque;
cont->cb(cont->bm, 0);
qemu_bh_delete(cont->bh);
qemu_free(cont);
}
static void continue_after_map_failure(void *opaque)
{
MapFailureContinuation *cont = opaque;
cont->bh = qemu_bh_new(reschedule_dma, opaque);
qemu_bh_schedule(cont->bh);
}
static void wait_for_bounce_buffer(BMDMAState *bmdma,
void (*cb)(void *opaque, int ret))
{
MapFailureContinuation *cont = qemu_malloc(sizeof(*cont));
cont->bm = bmdma;
cont->cb = cb;
cpu_register_map_client(cont, continue_after_map_failure);
}
static void ide_read_dma_cb(void *opaque, int ret)
{
BMDMAState *bm = opaque;
@ -948,6 +1044,7 @@ static void ide_read_dma_cb(void *opaque, int ret)
int64_t sector_num;
if (ret < 0) {
dma_buf_commit(s, 1);
ide_dma_error(s);
return;
}
@ -955,11 +1052,10 @@ static void ide_read_dma_cb(void *opaque, int ret)
n = s->io_buffer_size >> 9;
sector_num = ide_get_sector(s);
if (n > 0) {
dma_buf_commit(s, 1);
sector_num += n;
ide_set_sector(s, sector_num);
s->nsector -= n;
if (dma_buf_rw(bm, 1) == 0)
goto eot;
}
/* end of transfer ? */
@ -977,15 +1073,19 @@ static void ide_read_dma_cb(void *opaque, int ret)
/* launch next transfer */
n = s->nsector;
if (n > IDE_DMA_BUF_SECTORS)
n = IDE_DMA_BUF_SECTORS;
s->io_buffer_index = 0;
s->io_buffer_size = n * 512;
if (dma_buf_prepare(bm, 1) == 0)
goto eot;
if (!s->iovec.niov) {
wait_for_bounce_buffer(bm, ide_read_dma_cb);
return;
}
#ifdef DEBUG_AIO
printf("aio_read: sector_num=%" PRId64 " n=%d\n", sector_num, n);
#endif
bm->aiocb = bdrv_aio_read(s->bs, sector_num, s->io_buffer, n,
ide_read_dma_cb, bm);
bm->aiocb = bdrv_aio_readv(s->bs, sector_num, &s->iovec, n,
ide_read_dma_cb, bm);
ide_dma_submit_check(s, ide_read_dma_cb, bm);
}
@ -1081,6 +1181,7 @@ static void ide_write_dma_cb(void *opaque, int ret)
n = s->io_buffer_size >> 9;
sector_num = ide_get_sector(s);
if (n > 0) {
dma_buf_commit(s, 0);
sector_num += n;
ide_set_sector(s, sector_num);
s->nsector -= n;
@ -1099,20 +1200,20 @@ static void ide_write_dma_cb(void *opaque, int ret)
return;
}
/* launch next transfer */
n = s->nsector;
if (n > IDE_DMA_BUF_SECTORS)
n = IDE_DMA_BUF_SECTORS;
s->io_buffer_index = 0;
s->io_buffer_size = n * 512;
if (dma_buf_rw(bm, 0) == 0)
/* launch next transfer */
if (dma_buf_prepare(bm, 0) == 0)
goto eot;
if (!s->iovec.niov) {
wait_for_bounce_buffer(bm, ide_write_dma_cb);
return;
}
#ifdef DEBUG_AIO
printf("aio_write: sector_num=%" PRId64 " n=%d\n", sector_num, n);
#endif
bm->aiocb = bdrv_aio_write(s->bs, sector_num, s->io_buffer, n,
ide_write_dma_cb, bm);
bm->aiocb = bdrv_aio_writev(s->bs, sector_num, &s->iovec, n,
ide_write_dma_cb, bm);
ide_dma_submit_check(s, ide_write_dma_cb, bm);
}