The Block I/O protocol's io_align member tells the consumer what alignment the buffers passed to read_blocks()/write_blocks() need to have. We set it to the block size, but our implementation services all requests via cdev_read()/cdev_write(), which copy through the block layer's cache chunks regardless of the caller's buffer alignment, so there is no such requirement.
Report an io_align of 1 instead, which per UEFI specification, like 0, means the buffer can be placed anywhere in memory. Prefer 1 over 0 as a consumer computing the mask as io_align - 1 without checking for 0 first (as U-Boot's own producer side does) keeps working with 1, but would reject every buffer with 0. Assisted-by: Claude:fable-5 Signed-off-by: Ahmad Fatoum <[email protected]> --- efi/loader/protocols/disk.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/efi/loader/protocols/disk.c b/efi/loader/protocols/disk.c index 5c5447acca20..5376c9ec9a14 100644 --- a/efi/loader/protocols/disk.c +++ b/efi/loader/protocols/disk.c @@ -253,7 +253,13 @@ static efi_status_t efi_disk_add_cdev(efi_handle_t parent, diskobj->media.removable_media = removable; diskobj->media.media_present = true; diskobj->media.read_only = cdev->flags & DEVFS_PARTITION_READONLY; - diskobj->media.block_size = diskobj->media.io_align = 1u << blockbits; + diskobj->media.block_size = 1u << blockbits; + /* + * Reads and writes go through cdev_read()/cdev_write(), which + * always copy through the block layer cache, so any buffer + * alignment is acceptable. + */ + diskobj->media.io_align = 1; diskobj->media.last_block = (cdev->size >> blockbits) - 1; diskobj->blockbits = blockbits; -- 2.47.3
