[SeaBIOS] [PATCH v5 4/5] QEMU fw_cfg: Add functions for accessing files by key
Kevin O'Connor
kevin at koconnor.net
Mon Feb 20 16:38:25 CET 2017
On Fri, Feb 17, 2017 at 10:21:58PM -0800, ben at skyportsystems.com wrote:
> From: Ben Warren <ben at skyportsystems.com>
>
> When resuming from S3, only fw_cfg file keys are known.
>
> Signed-off-by: Ben Warren <ben at skyportsystems.com>
> ---
> src/fw/paravirt.c | 23 +++++++++++++++++++++++
> src/fw/paravirt.h | 2 ++
> 2 files changed, 25 insertions(+)
>
> diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c
> index 4618647..e513dd5 100644
> --- a/src/fw/paravirt.c
> +++ b/src/fw/paravirt.c
> @@ -352,6 +352,17 @@ qemu_cfg_write_file(void *src, struct romfile_s *file, u32 offset, u32 len)
> return len;
> }
>
> +// Bare-bones function for writing a file knowing only its unique
> +// identifying key (select)
> +int
> +qemu_cfg_write_file_simple(void *src, u16 key, u32 offset, u32 len)
> +{
> + qemu_cfg_select(key);
> + qemu_cfg_skip(offset);
> + qemu_cfg_write(src, len);
> + return len;
> +}
> +
> static void
> qemu_romfile_add(char *name, int select, int skip, int size)
> {
> @@ -370,6 +381,18 @@ qemu_romfile_add(char *name, int select, int skip, int size)
> }
>
> u16
> +qemu_get_romfile_key(struct romfile_s *file)
> +{
> + struct qemu_romfile_s *qfile;
> + qfile = container_of(file, struct qemu_romfile_s, file);
> + if (!qfile) {
> + warn_internalerror();
> + return 0;
> + }
This should verify that file->copy==qemu_cfg_read_file before calling
container_of. As Laszlo points out, there's no point in checking
!qfile after container_of.
-Kevin
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