From 23d0ba9319f182e258f480bafb7de9f79fb6e0e9 Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Tue, 16 Jan 2018 14:08:56 +0800 Subject: block: Introduce buf register API Allow block driver to map and unmap a buffer for later I/O, as a performance hint. Signed-off-by: Fam Zheng Reviewed-by: Stefan Hajnoczi Message-Id: <20180116060901.17413-5-famz@redhat.com> Signed-off-by: Fam Zheng --- include/block/block.h | 11 ++++++++++- include/block/block_int.h | 9 +++++++++ include/sysemu/block-backend.h | 3 +++ 3 files changed, 22 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/block/block.h b/include/block/block.h index 9b12774..2025d7e 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -631,5 +631,14 @@ void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp); bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name, uint32_t granularity, Error **errp); - +/** + * + * bdrv_register_buf/bdrv_unregister_buf: + * + * Register/unregister a buffer for I/O. For example, VFIO drivers are + * interested to know the memory areas that would later be used for I/O, so + * that they can prepare IOMMU mapping etc., to get better performance. + */ +void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size); +void bdrv_unregister_buf(BlockDriverState *bs, void *host); #endif diff --git a/include/block/block_int.h b/include/block/block_int.h index 29cafa4..99b9190 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -446,6 +446,15 @@ struct BlockDriver { const char *name, Error **errp); + /** + * Register/unregister a buffer for I/O. For example, when the driver is + * interested to know the memory areas that will later be used in iovs, so + * that it can do IOMMU mapping with VFIO etc., in order to get better + * performance. In the case of VFIO drivers, this callback is used to do + * DMA mapping for hot buffers. + */ + void (*bdrv_register_buf)(BlockDriverState *bs, void *host, size_t size); + void (*bdrv_unregister_buf)(BlockDriverState *bs, void *host); QLIST_ENTRY(BlockDriver) list; }; diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h index c4e52a5..92ab624 100644 --- a/include/sysemu/block-backend.h +++ b/include/sysemu/block-backend.h @@ -229,4 +229,7 @@ void blk_io_limits_enable(BlockBackend *blk, const char *group); void blk_io_limits_update_group(BlockBackend *blk, const char *group); void blk_set_force_allow_inactivate(BlockBackend *blk); +void blk_register_buf(BlockBackend *blk, void *host, size_t size); +void blk_unregister_buf(BlockBackend *blk, void *host); + #endif -- cgit v1.1