On 03/19/2012 08:14 AM, Zhang, Yang Z wrote: > The new logic is compatible with old. So it should not block migrate from old version. But new version cannot migrate to old. > > +static int rtc_load_old(QEMUFile *f, void *opaque, int version_id) > +{ > + RTCState *s = opaque; > + > + if (version_id > 2) { > + return -EINVAL; > + } > + > + qemu_get_buffer(f, s->cmos_data, sizeof(s->cmos_data)); > + /* dummy load for compatibility */ > + qemu_get_byte(f); /* cmos_index */ > + qemu_get_be32(f); /* tm_sec */ > + qemu_get_be32(f); /* tm_min */ > + qemu_get_be32(f); /* tm_hour */ > + qemu_get_be32(f); /* tm_wday */ > + qemu_get_be32(f); /* tm_mday */ > + qemu_get_be32(f); /* tm_mon */ > + qemu_get_be32(f); /* tm_year */ > + qemu_get_be64(f); /* periodic_timer */ > + qemu_get_be64(f); /* next_periodic_time */ > + qemu_get_be64(f); /* next_second_time */ > + qemu_get_be64(f); /* second_timer */ > + qemu_get_be64(f); /* second_timer2 */ > + qemu_get_be32(f); /* irq_coalesced */ > + qemu_get_be32(f); /* period */ > + Why don't you just convert the data to the new in-memory format? Then you don't need a version update. > + > + rtc_set_date_from_host(&s->dev); If the guest is intentionally running with an incorrect date, this breaks. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html