Re: [PATCH v2 07/17] migration: Add qemu_loadvm_load_state_buffer() and its handler

[Maciej S. Szmigiero]

On 5.09.2024 16:15, Avihai Horon wrote:
> On 27/08/2024 20:54, Maciej S. Szmigiero wrote:
> > External email: Use caution opening links or attachments
> >
> >
> > 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.
> >
> > Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
> > ---
> >   include/migration/register.h | 15 +++++++++++++++
> >   migration/savevm.c           | 25 +++++++++++++++++++++++++
> >   migration/savevm.h           |  3 +++
> >   3 files changed, 43 insertions(+)
> >
> > diff --git a/include/migration/register.h b/include/migration/register.h
> > index 9de123252edf..4a578f140713 100644
> > --- a/include/migration/register.h
> > +++ b/include/migration/register.h
> > @@ -263,6 +263,21 @@ typedef struct SaveVMHandlers {
> >        */
> >       int (*load_state)(QEMUFile *f, void *opaque, int version_id);
> >
> > +    /**
> > +     * @load_state_buffer
> > +     *
> > +     * Load device state buffer provided to qemu_loadvm_load_state_buffer().
> > +     *
> > +     * @opaque: data pointer passed to register_savevm_live()
> > +     * @data: the data buffer to load
> > +     * @data_size: 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 *data, size_t data_size,
> > +                             Error **errp);
>
> Nit: Maybe rename data to buf and data_size to len to be consistent with 
> qemu_loadvm_load_state_buffer()?

Will do.

> > +
> >       /**
> >        * @load_setup
> >        *
> > diff --git a/migration/savevm.c b/migration/savevm.c
> > index d43acbbf20cf..3fde5ca8c26b 100644
> > --- a/migration/savevm.c
> > +++ b/migration/savevm.c
> > @@ -3101,6 +3101,31 @@ 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)
> > +{
> > +    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;
> > +    }
> > +
> > +    if (se->ops->load_state_buffer(se->opaque, buf, len, errp) != 0) {
> > +        return -1;
> > +    }
> > +
> > +    return 0;
>
> Nit: this can be simplified to:
> return se->ops->load_state_buffer(se->opaque, buf, len, errp);
You're right - will change it so.
 
> Thanks.

Thanks,
Maciej