Am 09.03.2012 06:01, schrieb David Gibson:
> dma-helpers.c contains a number of helper functions for doing
> scatter/gather DMA, and various block device related DMA. Currently,
> these directly access guest memory using cpu_physical_memory_*(),
> assuming no IOMMU translation.
>
> This patch updates this code to use the new universal DMA helper
> functions. qemu_sglist_init() now takes a DMAContext * to describe
> the DMA address space in which the scatter/gather will take place.
>
> We minimally update the callers qemu_sglist_init() to pass NULL
> (i.e. no translation, same as current behaviour). Some of those
> callers should pass something else in some cases to allow proper IOMMU
> translation in future, but that will be fixed in later patches.
>
> Cc: Kevin Wolf <kw...@redhat.com>
> Cc: Michael S. Tsirkin <m...@redhat.com>
>
> Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
> ---
> dma-helpers.c | 26 ++++++++++++++++++--------
> dma.h | 3 ++-
> hw/ide/ahci.c | 3 ++-
> hw/ide/macio.c | 4 ++--
> hw/pci.h | 2 +-
> 5 files changed, 25 insertions(+), 13 deletions(-)
>
> diff --git a/dma-helpers.c b/dma-helpers.c
> index 5f19a85..9dcfb2c 100644
> --- a/dma-helpers.c
> +++ b/dma-helpers.c
> @@ -11,12 +11,13 @@
> #include "block_int.h"
> #include "trace.h"
>
> -void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint)
> +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)
> @@ -75,10 +76,9 @@ static void dma_bdrv_unmap(DMAAIOCB *dbs)
> int i;
>
> 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->dir != DMA_DIRECTION_TO_DEVICE,
> - dbs->iov.iov[i].iov_len);
> + 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);
> }
> @@ -104,10 +104,20 @@ static void dma_complete(DMAAIOCB *dbs, int ret)
> }
> }
>
> +static void dma_bdrv_cancel(void *opaque)
> +{
> + DMAAIOCB *dbs = opaque;
> +
> + bdrv_aio_cancel(dbs->acb);
> + dma_bdrv_unmap(dbs);
> + qemu_iovec_destroy(&dbs->iov);
> + qemu_aio_release(dbs);
> +}
I'm lacking the context to know when this is actually called, but it
looks suspicious. Did you consider that bdrv_aio_cancel() can actually
invoke the completion callback?
What's the difference between the existing dma_aio_cancel() and the
function that you need here?
Kevin
