On Sun, Nov 17, 2024 at 08:20:01PM +0100, Maciej S. Szmigiero wrote:
> From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com>
>
> qemu_loadvm_load_state_buffer() and its load_state_buffer
> SaveVMHandler allow providing device state buffer to explicitly
> specified device via its idstr and instance id.
>
> Reviewed-by: Fabiano Rosas <farosas@suse.de>
> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
One nitpick:
> ---
> include/migration/register.h | 17 +++++++++++++++++
> migration/savevm.c | 23 +++++++++++++++++++++++
> migration/savevm.h | 3 +++
> 3 files changed, 43 insertions(+)
>
> diff --git a/include/migration/register.h b/include/migration/register.h
> index ff0faf5f68c8..39991f3cc5d0 100644
> --- a/include/migration/register.h
> +++ b/include/migration/register.h
> @@ -229,6 +229,23 @@ typedef struct SaveVMHandlers {
> */
> int (*load_state)(QEMUFile *f, void *opaque, int version_id);
>
> + /* This runs outside the BQL. */
> +
> + /**
> + * @load_state_buffer
> + *
> + * Load device state buffer provided to qemu_loadvm_load_state_buffer().
> + *
> + * @opaque: data pointer passed to register_savevm_live()
> + * @buf: the data buffer to load
> + * @len: the data length in buffer
> + * @errp: pointer to Error*, to store an error if it happens.
> + *
> + * Returns zero to indicate success and negative for error
> + */
> + int (*load_state_buffer)(void *opaque, char *buf, size_t len,
> + Error **errp);
> +
> /**
> * @load_setup
> *
> diff --git a/migration/savevm.c b/migration/savevm.c
> index a254c38edcca..1f58a2fa54ae 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -3085,6 +3085,29 @@ int qemu_loadvm_approve_switchover(void)
> return migrate_send_rp_switchover_ack(mis);
> }
>
> +int qemu_loadvm_load_state_buffer(const char *idstr, uint32_t instance_id,
> + char *buf, size_t len, Error **errp)
Suggest to always return bool as success/fail, especially when using
Error**.
> +{
> + SaveStateEntry *se;
> +
> + se = find_se(idstr, instance_id);
> + if (!se) {
> + error_setg(errp,
> + "Unknown idstr %s or instance id %u for load state buffer",
> + idstr, instance_id);
> + return -1;
> + }
> +
> + if (!se->ops || !se->ops->load_state_buffer) {
> + error_setg(errp,
> + "idstr %s / instance %u has no load state buffer operation",
> + idstr, instance_id);
> + return -1;
> + }
> +
> + return se->ops->load_state_buffer(se->opaque, buf, len, errp);
> +}
> +
> bool save_snapshot(const char *name, bool overwrite, const char *vmstate,
> bool has_devices, strList *devices, Error **errp)
> {
> diff --git a/migration/savevm.h b/migration/savevm.h
> index 4d402723bc3c..b5a4f8c8b440 100644
> --- a/migration/savevm.h
> +++ b/migration/savevm.h
> @@ -71,4 +71,7 @@ int qemu_loadvm_approve_switchover(void);
> int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f,
> bool in_postcopy, bool inactivate_disks);
>
> +int qemu_loadvm_load_state_buffer(const char *idstr, uint32_t instance_id,
> + char *buf, size_t len, Error **errp);
> +
> #endif
>
--
Peter Xu