fw-cfg: support writeable blobs

Useful to send guest data back to QEMU.

Changes from Laszlo Ersek <lersek@redhat.com>:
- rebase the patch from Michael Tsirkin's original postings at [1] and [2]
  to the following patches:
  - loader: Allow a custom AddressSpace when loading ROMs
  - loader: Add AddressSpace loading support to uImages
  - loader: fix handling of custom address spaces when adding ROM blobs
- reject such writes immediately that would exceed the end of the array,
  rather than performing a partial write before setting the error bit: see
  the (len != dma.length) condition
- document the write interface

[1] http://lists.nongnu.org/archive/html/qemu-devel/2016-02/msg04968.html
[2] http://lists.nongnu.org/archive/html/qemu-devel/2016-03/msg02735.html

Cc: "Gabriel L. Somlo" <somlo@cmu.edu>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Michael Walle <michael@walle.cc>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Shannon Zhao <zhaoshenglong@huawei.com>
Cc: qemu-arm@nongnu.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>
Acked-by: Gabriel Somlo <somlo@cmu.edu>
Tested-by: Gabriel Somlo <somlo@cmu.edu>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
This commit is contained in:
Michael S. Tsirkin 2017-01-12 19:24:14 +01:00
parent c471ad0e9b
commit baf2d5bfba
8 changed files with 75 additions and 30 deletions

View file

@ -136,6 +136,7 @@ void fw_cfg_add_file(FWCfgState *s, const char *filename, void *data,
* @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 NAMED fw_cfg item as a raw "blob" of the given size. The data
* referenced by the starting pointer is only linked, NOT copied, into the
@ -151,7 +152,7 @@ void fw_cfg_add_file(FWCfgState *s, const char *filename, void *data,
*/
void fw_cfg_add_file_callback(FWCfgState *s, const char *filename,
FWCfgReadCallback callback, void *callback_opaque,
void *data, size_t len);
void *data, size_t len, bool read_only);
/**
* fw_cfg_modify_file: