From e935b735085dfa61d8e6d276b6f9e7687796a3c7 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Wed, 21 Sep 2022 11:31:31 +0200 Subject: x86: return modified setup_data only if read as memory, not as file MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If setup_data is being read into a specific memory location, then generally the setup_data address parameter is read first, so that the caller knows where to read it into. In that case, we should return setup_data containing the absolute addresses that are hard coded and determined a priori. This is the case when kernels are loaded by BIOS, for example. In contrast, when setup_data is read as a file, then we shouldn't modify setup_data, since the absolute address will be wrong by definition. This is the case when OVMF loads the image. This allows setup_data to be used like normal, without crashing when EFI tries to use it. (As a small development note, strangely, fw_cfg_add_file_callback() was exported but fw_cfg_add_bytes_callback() wasn't, so this makes that consistent.) Cc: Gerd Hoffmann Cc: Laurent Vivier Cc: Michael S. Tsirkin Cc: Paolo Bonzini Cc: Peter Maydell Cc: Philippe Mathieu-Daudé Cc: Richard Henderson Suggested-by: Ard Biesheuvel Reviewed-by: Ard Biesheuvel Signed-off-by: Jason A. Donenfeld Message-Id: <20220921093134.2936487-1-Jason@zx2c4.com> Signed-off-by: Paolo Bonzini --- include/hw/nvram/fw_cfg.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'include/hw') diff --git a/include/hw/nvram/fw_cfg.h b/include/hw/nvram/fw_cfg.h index 0e7a8bc7af..e4fef393be 100644 --- a/include/hw/nvram/fw_cfg.h +++ b/include/hw/nvram/fw_cfg.h @@ -117,6 +117,28 @@ struct FWCfgMemState { */ void fw_cfg_add_bytes(FWCfgState *s, uint16_t key, void *data, size_t len); +/** + * fw_cfg_add_bytes_callback: + * @s: fw_cfg device being modified + * @key: selector key value for new fw_cfg item + * @select_cb: callback function when selecting + * @write_cb: callback function after a write + * @callback_opaque: argument to be passed into callback function + * @data: pointer to start of item data + * @len: size of item data + * @read_only: is file read only + * + * Add a new fw_cfg item, available by selecting the given key, as a raw + * "blob" of the given size. The data referenced by the starting pointer + * is only linked, NOT copied, into the data structure of the fw_cfg device. + */ +void fw_cfg_add_bytes_callback(FWCfgState *s, uint16_t key, + FWCfgCallback select_cb, + FWCfgWriteCallback write_cb, + void *callback_opaque, + void *data, size_t len, + bool read_only); + /** * fw_cfg_add_string: * @s: fw_cfg device being modified -- cgit v1.2.3