From 4f384011c5a37f80dc6cadefffac61ffb1c3aa1e Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Thu, 13 Oct 2022 14:58:59 -0400 Subject: block: pass size to bdrv_unregister_buf() The only implementor of bdrv_register_buf() is block/nvme.c, where the size is not needed when unregistering a buffer. This is because util/vfio-helpers.c can look up mappings by address. Future block drivers that implement bdrv_register_buf() may not be able to do their job given only the buffer address. Add a size argument to bdrv_unregister_buf(). Also document the assumptions about bdrv_register_buf()/bdrv_unregister_buf() calls. The same values that were given to bdrv_register_buf() must be given to bdrv_unregister_buf(). gcc 11.2.1 emits a spurious warning that img_bench()'s buf_size local variable might be uninitialized, so it's necessary to silence the compiler. Signed-off-by: Stefan Hajnoczi Reviewed-by: Stefano Garzarella Message-id: 20221013185908.1297568-5-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi --- include/block/block-global-state.h | 5 ++++- include/block/block_int-common.h | 2 +- include/sysemu/block-backend-global-state.h | 2 +- 3 files changed, 6 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/block/block-global-state.h b/include/block/block-global-state.h index 21265e3966..7901f35863 100644 --- a/include/block/block-global-state.h +++ b/include/block/block-global-state.h @@ -243,9 +243,12 @@ void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp); * 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. + * + * Buffers must not overlap and they must be unregistered with the same values that they were registered with. */ void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size); -void bdrv_unregister_buf(BlockDriverState *bs, void *host); +void bdrv_unregister_buf(BlockDriverState *bs, void *host, size_t size); void bdrv_cancel_in_flight(BlockDriverState *bs); diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h index 8947abab76..b7a7cbd3a5 100644 --- a/include/block/block_int-common.h +++ b/include/block/block_int-common.h @@ -435,7 +435,7 @@ struct BlockDriver { * DMA mapping for hot buffers. */ void (*bdrv_register_buf)(BlockDriverState *bs, void *host, size_t size); - void (*bdrv_unregister_buf)(BlockDriverState *bs, void *host); + void (*bdrv_unregister_buf)(BlockDriverState *bs, void *host, size_t size); /* * This field is modified only under the BQL, and is part of diff --git a/include/sysemu/block-backend-global-state.h b/include/sysemu/block-backend-global-state.h index 415f0c91d7..97f7dad2c3 100644 --- a/include/sysemu/block-backend-global-state.h +++ b/include/sysemu/block-backend-global-state.h @@ -107,7 +107,7 @@ 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); +void blk_unregister_buf(BlockBackend *blk, void *host, size_t size); const BdrvChild *blk_root(BlockBackend *blk); -- cgit v1.2.3-55-g7522