diff options
| -rw-r--r-- | block.c | 23 | ||||
| -rw-r--r-- | include/block/block.h | 3 | ||||
| -rw-r--r-- | include/block/block_int.h | 3 |
3 files changed, 26 insertions, 3 deletions
diff --git a/block.c b/block.c index 275d387354..e5f214d135 100644 --- a/block.c +++ b/block.c @@ -218,6 +218,16 @@ static void bdrv_io_limits_intercept(BlockDriverState *bs, qemu_co_queue_next(&bs->throttled_reqs[is_write]); } +size_t bdrv_opt_mem_align(BlockDriverState *bs) +{ + if (!bs || !bs->drv) { + /* 4k should be on the safe side */ + return 4096; + } + + return bs->bl.opt_mem_alignment; +} + /* check if the path starts with "<protocol>:" */ static int path_has_protocol(const char *path) { @@ -497,6 +507,9 @@ int bdrv_refresh_limits(BlockDriverState *bs) if (bs->file) { bdrv_refresh_limits(bs->file); bs->bl.opt_transfer_length = bs->file->bl.opt_transfer_length; + bs->bl.opt_mem_alignment = bs->file->bl.opt_mem_alignment; + } else { + bs->bl.opt_mem_alignment = 512; } if (bs->backing_hd) { @@ -504,6 +517,9 @@ int bdrv_refresh_limits(BlockDriverState *bs) bs->bl.opt_transfer_length = MAX(bs->bl.opt_transfer_length, bs->backing_hd->bl.opt_transfer_length); + bs->bl.opt_mem_alignment = + MAX(bs->bl.opt_mem_alignment, + bs->backing_hd->bl.opt_mem_alignment); } /* Then let the driver override it */ @@ -4797,7 +4813,7 @@ void bdrv_set_buffer_alignment(BlockDriverState *bs, int align) void *qemu_blockalign(BlockDriverState *bs, size_t size) { - return qemu_memalign((bs && bs->buffer_alignment) ? bs->buffer_alignment : 512, size); + return qemu_memalign(bdrv_opt_mem_align(bs), size); } /* @@ -4806,12 +4822,13 @@ void *qemu_blockalign(BlockDriverState *bs, size_t size) bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov) { int i; + size_t alignment = bdrv_opt_mem_align(bs); for (i = 0; i < qiov->niov; i++) { - if ((uintptr_t) qiov->iov[i].iov_base % bs->buffer_alignment) { + if ((uintptr_t) qiov->iov[i].iov_base % alignment) { return false; } - if (qiov->iov[i].iov_len % bs->buffer_alignment) { + if (qiov->iov[i].iov_len % alignment) { return false; } } diff --git a/include/block/block.h b/include/block/block.h index 00a8790660..332ebb94fb 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -428,6 +428,9 @@ void bdrv_img_create(const char *filename, const char *fmt, char *options, uint64_t img_size, int flags, Error **errp, bool quiet); +/* Returns the alignment in bytes that is required so that no bounce buffer + * is required throughout the stack */ +size_t bdrv_opt_mem_align(BlockDriverState *bs); void bdrv_set_buffer_alignment(BlockDriverState *bs, int align); void *qemu_blockalign(BlockDriverState *bs, size_t size); bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov); diff --git a/include/block/block_int.h b/include/block/block_int.h index f6fa1f6f36..74a78a6831 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -258,6 +258,9 @@ typedef struct BlockLimits { /* optimal transfer length in sectors */ int opt_transfer_length; + + /* memory alignment so that no bounce buffer is needed */ + size_t opt_mem_alignment; } BlockLimits; /* |