Commit 23d0ba93 authored by Fam Zheng's avatar Fam Zheng
Browse files

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: default avatarFam Zheng <famz@redhat.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20180116060901.17413-5-famz@redhat.com>
Signed-off-by: default avatarFam Zheng <famz@redhat.com>
parent bdd6a90a

block/block-backend.c

+10 −0
Original line number Diff line number Diff line
@@ -2096,3 +2096,13 @@ static void blk_root_drained_end(BdrvChild *child) 
        }

    }

}



void blk_register_buf(BlockBackend *blk, void *host, size_t size)

{

    bdrv_register_buf(blk_bs(blk), host, size);

}



void blk_unregister_buf(BlockBackend *blk, void *host)

{

    bdrv_unregister_buf(blk_bs(blk), host);

}

block/io.c

+24 −0
Original line number Diff line number Diff line
@@ -2825,3 +2825,27 @@ void bdrv_io_unplug(BlockDriverState *bs) 
        bdrv_io_unplug(child->bs);

    }

}



void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size)

{

    BdrvChild *child;



    if (bs->drv && bs->drv->bdrv_register_buf) {

        bs->drv->bdrv_register_buf(bs, host, size);

    }

    QLIST_FOREACH(child, &bs->children, next) {

        bdrv_register_buf(child->bs, host, size);

    }

}



void bdrv_unregister_buf(BlockDriverState *bs, void *host)

{

    BdrvChild *child;



    if (bs->drv && bs->drv->bdrv_unregister_buf) {

        bs->drv->bdrv_unregister_buf(bs, host);

    }

    QLIST_FOREACH(child, &bs->children, next) {

        bdrv_unregister_buf(child->bs, host);

    }

}

include/block/block.h

+10 −1
Original line number Diff line number Diff line
@@ -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

include/block/block_int.h

+9 −0
Original line number Diff line number Diff line
@@ -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;

};

include/sysemu/block-backend.h

+3 −0
Original line number Diff line number Diff line
@@ -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