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[Qemu-devel] [6524] Introduce block dma helpers (Avi Kivity)
From: |
Anthony Liguori |
Subject: |
[Qemu-devel] [6524] Introduce block dma helpers (Avi Kivity) |
Date: |
Thu, 05 Feb 2009 21:23:58 +0000 |
Revision: 6524
http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=6524
Author: aliguori
Date: 2009-02-05 21:23:58 +0000 (Thu, 05 Feb 2009)
Log Message:
-----------
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 <address@hidden>
Signed-off-by: Anthony Liguori <address@hidden>
Modified Paths:
--------------
trunk/dma-helpers.c
trunk/dma.h
Modified: trunk/dma-helpers.c
===================================================================
--- trunk/dma-helpers.c 2009-02-05 21:23:54 UTC (rev 6523)
+++ trunk/dma-helpers.c 2009-02-05 21:23:58 UTC (rev 6524)
@@ -8,8 +8,8 @@
*/
#include "dma.h"
+#include "block_int.h"
-
void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint)
{
qsg->sg = qemu_malloc(alloc_hint * sizeof(ScatterGatherEntry));
@@ -36,3 +36,120 @@
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);
+}
+
Modified: trunk/dma.h
===================================================================
--- trunk/dma.h 2009-02-05 21:23:54 UTC (rev 6523)
+++ trunk/dma.h 2009-02-05 21:23:58 UTC (rev 6524)
@@ -12,6 +12,7 @@
#include <stdio.h>
#include "cpu.h"
+#include "block.h"
typedef struct {
target_phys_addr_t base;
@@ -30,4 +31,11 @@
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
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