On Tue, Aug 14, 2018 at 9:27 AM, Stefan Hajnoczi <stefa...@redhat.com> wrote:
> Image file loaders may add a series of roms. If an error occurs partway
> through loading there is no easy way to drop previously added roms.
>
> This patch adds a transaction mechanism that works like this:
>
> rom_transaction_begin();
> ...call rom_add_*()...
> rom_transaction_end(ok);
>
> If ok is false then roms added in this transaction are dropped.
>
> Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
Reviewed-by: Alistair Francis <alistair.fran...@wdc.com>
Alistair
> ---
> include/hw/loader.h | 19 +++++++++++++++++++
> hw/core/loader.c | 32 ++++++++++++++++++++++++++++++++
> 2 files changed, 51 insertions(+)
>
> diff --git a/include/hw/loader.h b/include/hw/loader.h
> index e98b84b8f9..5235f119a3 100644
> --- a/include/hw/loader.h
> +++ b/include/hw/loader.h
> @@ -225,6 +225,25 @@ int rom_check_and_register_reset(void);
> void rom_set_fw(FWCfgState *f);
> void rom_set_order_override(int order);
> void rom_reset_order_override(void);
> +
> +/**
> + * rom_transaction_begin:
> + *
> + * Call this before of a series of rom_add_*() calls. Call
> + * rom_transaction_end() afterwards to commit or abort. These functions are
> + * useful for undoing a series of rom_add_*() calls if image file loading
> fails
> + * partway through.
> + */
> +void rom_transaction_begin(void);
> +
> +/**
> + * rom_transaction_end:
> + * @commit: true to commit added roms, false to drop added roms
> + *
> + * Call this after a series of rom_add_*() calls. See
> rom_transaction_begin().
> + */
> +void rom_transaction_end(bool commit);
> +
> int rom_copy(uint8_t *dest, hwaddr addr, size_t size);
> void *rom_ptr(hwaddr addr, size_t size);
> void hmp_info_roms(Monitor *mon, const QDict *qdict);
> diff --git a/hw/core/loader.c b/hw/core/loader.c
> index 0c72e7c05a..612420b870 100644
> --- a/hw/core/loader.c
> +++ b/hw/core/loader.c
> @@ -840,6 +840,8 @@ struct Rom {
> char *fw_dir;
> char *fw_file;
>
> + bool committed;
> +
> hwaddr addr;
> QTAILQ_ENTRY(Rom) next;
> };
> @@ -877,6 +879,8 @@ static void rom_insert(Rom *rom)
> rom->as = &address_space_memory;
> }
>
> + rom->committed = false;
> +
> /* List is ordered by load address in the same address space */
> QTAILQ_FOREACH(item, &roms, next) {
> if (rom_order_compare(rom, item)) {
> @@ -1168,6 +1172,34 @@ void rom_reset_order_override(void)
> fw_cfg_reset_order_override(fw_cfg);
> }
>
> +void rom_transaction_begin(void)
> +{
> + Rom *rom;
> +
> + /* Ignore ROMs added without the transaction API */
> + QTAILQ_FOREACH(rom, &roms, next) {
> + rom->committed = true;
> + }
> +}
> +
> +void rom_transaction_end(bool commit)
> +{
> + Rom *rom;
> + Rom *tmp;
> +
> + QTAILQ_FOREACH_SAFE(rom, &roms, next, tmp) {
> + if (rom->committed) {
> + continue;
> + }
> + if (commit) {
> + rom->committed = true;
> + } else {
> + QTAILQ_REMOVE(&roms, rom, next);
> + rom_free(rom);
> + }
> + }
> +}
> +
> static Rom *find_rom(hwaddr addr, size_t size)
> {
> Rom *rom;
> --
> 2.17.1
>
>
