[Qemu-devel] Re: [PATCH 3/4] Introduce block dma helpers

[Anthony Liguori <aliguori@us.ibm.com>]

Avi Kivity wrote:
> 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>
>   
<snip>
> +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);
> +}
>   

This came out really nicely.

Regards,

Anthony Liguori

> diff --git a/dma.h b/dma.h
> index 3b56fa6..5ce54fb 100644
> --- a/dma.h
> +++ b/dma.h
> @@ -3,6 +3,7 @@
>  
>  #include <stdio.h>
>  #include "cpu.h"
> +#include "block.h"
>  
>  typedef struct {
>      target_phys_addr_t base;
> @@ -21,4 +22,11 @@ void qemu_sglist_add(QEMUSGList *qsg, target_phys_addr_t base,
>                       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
>