[SeaBIOS] [PATCH v7 5/5] QEMU fw_cfg: Write fw_cfg back on S3 resume
Kevin O'Connor
kevin at koconnor.net
Tue Feb 21 15:42:13 CET 2017
On Mon, Feb 20, 2017 at 07:56:19PM -0800, ben at skyportsystems.com wrote:
> From: Ben Warren <ben at skyportsystems.com>
>
> Any pointers to BIOS-allocated memory that were written back to QEMU
> fw_cfg files are replayed when resuming from S3 sleep.
>
> Signed-off-by: Ben Warren <ben at skyportsystems.com>
> Reviewed-by: Laszlo Ersek <lersek at redhat.com>
> ---
> src/fw/romfile_loader.c | 33 +++++++++++++++++++++++++++++++++
> src/fw/romfile_loader.h | 2 ++
> src/resume.c | 4 ++++
> 3 files changed, 39 insertions(+)
>
> diff --git a/src/fw/romfile_loader.c b/src/fw/romfile_loader.c
> index 30e7b58..14bc908 100644
> --- a/src/fw/romfile_loader.c
> +++ b/src/fw/romfile_loader.c
> @@ -4,6 +4,7 @@
> #include "string.h" // strcmp
> #include "romfile.h" // struct romfile_s
> #include "malloc.h" // Zone*, _malloc
> +#include "list.h" // struct hlist_node
> #include "output.h" // warn_*
> #include "paravirt.h" // qemu_cfg_write_file
>
> @@ -16,6 +17,16 @@ struct romfile_loader_files {
> struct romfile_loader_file files[];
> };
>
> +// Data structures for storing "write pointer" entries for possible replay
> +struct romfile_wr_pointer_entry {
> + u64 pointer;
> + u32 offset;
> + u16 key;
> + u8 ptr_size;
> + struct hlist_node node;
> +};
> +static struct hlist_head romfile_pointer_list;
> +
> static struct romfile_loader_file *
> romfile_loader_find(const char *name,
> struct romfile_loader_files *files)
> @@ -29,6 +40,19 @@ romfile_loader_find(const char *name,
> return NULL;
> }
>
> +// Replay "write pointer" entries back to QEMU
> +void romfile_fw_cfg_resume(void)
> +{
> + if (!CONFIG_QEMU)
> + return;
> +
> + struct romfile_wr_pointer_entry *entry;
> + hlist_for_each_entry(entry, &romfile_pointer_list, node) {
> + qemu_cfg_write_file_simple(&entry->pointer, entry->key,
> + entry->offset, entry->ptr_size);
> + }
> +}
> +
> static void romfile_loader_allocate(struct romfile_loader_entry_s *entry,
> struct romfile_loader_files *files)
> {
> @@ -163,6 +187,15 @@ static void romfile_loader_write_pointer(struct romfile_loader_entry_s *entry,
> entry->wr_pointer.size) != entry->wr_pointer.size) {
> goto err;
> }
> +
> + /* Store the info so it can replayed later if necessary */
> + struct romfile_wr_pointer_entry *store = malloc_high(sizeof(*store));
> + store->pointer = pointer;
I missed this in my earlier review - it's necessary to always check
the return of malloc() in seabios. (Writing to NULL changes memory at
address 0 which is shared with the 16bit interrupt table.) I fixed it
upon commit.
-Kevin
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