On 23.12.14 01:17, David Gibson wrote:
> The initial creation of the PAPR RTC qdev class left a wart - the rtc's
> offset was left in the sPAPREnvironment structure, accessed via a global.
>
> This patch moves it into the RTC device's own state structure, were it
> belongs. This requires a small change to the migration stream format. In
> order to handle incoming streams from older versions, we also need to
> retain the rtc_offset field in the sPAPREnvironment structure, so that it
> can be loaded into via the vmsd, then pushed into the RTC device.
>
> Since we're changing the migration format, this also takes the opportunity
> to change the rtc offset from a value in seconds to a value in nanoseconds,
> allowing nanosecond offsets between host and guest rtc time, if desired.
>
> Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
> ---
> hw/ppc/spapr.c | 19 ++++++++++++++++++-
> hw/ppc/spapr_rtc.c | 41 +++++++++++++++++++++++++++++++++++++----
> include/hw/ppc/spapr.h | 3 ++-
> 3 files changed, 57 insertions(+), 6 deletions(-)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 9722b42..3070be0 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -980,10 +980,27 @@ static int spapr_vga_init(PCIBus *pci_bus)
> }
> }
>
> +static int spapr_post_load(void *opaque, int version_id)
> +{
> + sPAPREnvironment *spapr = (sPAPREnvironment *)opaque;
> + int err = 0;
> +
> + /* In earlier versions, there was no seperate qdev for the PAPR
> + * RTC, so the RTC offset was stored directly in sPAPREnvironment.
> + * So when migrating from those versions, poke the incoming offset
> + * value into the RTC device */
> + if (version_id < 3) {
> + err = spapr_rtc_import_offset(spapr->rtc, spapr->rtc_offset);
Do you think you could do this via a qom property set rather than an
explicit function call into the rtc code base instead?
> + }
> +
> + return err;
> +}
> +
> static const VMStateDescription vmstate_spapr = {
> .name = "spapr",
> - .version_id = 2,
> + .version_id = 3,
> .minimum_version_id = 1,
> + .post_load = spapr_post_load,
> .fields = (VMStateField[]) {
> VMSTATE_UNUSED(4), /* used to be @next_irq */
Shouldn't we make the rtc_offset field conditional on version < 3 as
well here? In fact, you could do the same for the legacy next_irq. That
way we don't need to move data over the wire that doesn't get used anymore.
Alex
