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authoraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>2009-02-05 21:23:58 +0000
committeraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>2009-02-05 21:23:58 +0000
commit59a703ebaa9cb5aeda986dc8f627b8d23e3297cd (patch)
tree409d817d5e499297da04543b88823c7fcd6a3c04 /dma-helpers.c
parentbe959463afd3e257611d6b6ab98d24c0c94d4e3d (diff)
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 <avi@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6524 c046a42c-6fe2-441c-8c8c-71466251a162
Diffstat (limited to 'dma-helpers.c')
-rw-r--r--dma-helpers.c119
1 files changed, 118 insertions, 1 deletions
diff --git a/dma-helpers.c b/dma-helpers.c
index 11ad3a434..b2ade19ac 100644
--- a/dma-helpers.c
+++ b/dma-helpers.c
@@ -8,7 +8,7 @@
*/
#include "dma.h"
-
+#include "block_int.h"
void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint)
{
@@ -36,3 +36,120 @@ void qemu_sglist_destroy(QEMUSGList *qsg)
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);
+}
+