Re: [Qemu-devel] [PATCHv2 4/5] Revert "spapr: Fix migration of PCI host bridges from qemu-2.7"

[Thomas Huth <thuth@redhat.com>]

On 21.11.2016 06:31, David Gibson wrote:
> This reverts commit 9b54ca0ba781012eeea4237b7c4832ba2ea81d89.
> 
> The commit above corrected a migration breakage between qemu-2.7 and
> qemu-2.8.  However it did so by advancing the migration version for
> the PCI host bridge, which obviously breaks migration backwards to
> earlier qemu versions.
> 
> Although it's not totally essential, we'd like to maintain the
> possibility for backwards migration, so revert the change in
> preparation for a better fix.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>  hw/ppc/spapr_pci.c | 18 ++++++------------
>  1 file changed, 6 insertions(+), 12 deletions(-)
> 
> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> index 661f7d8..e429c94 100644
> --- a/hw/ppc/spapr_pci.c
> +++ b/hw/ppc/spapr_pci.c
> @@ -1680,25 +1680,19 @@ static int spapr_pci_post_load(void *opaque, int version_id)
>      return 0;
>  }
>  
> -static bool version_before_3(void *opaque, int version_id)
> -{
> -    return version_id < 3;
> -}
> -
>  static const VMStateDescription vmstate_spapr_pci = {
>      .name = "spapr_pci",
> -    .version_id = 3,
> +    .version_id = 2,
>      .minimum_version_id = 2,
>      .pre_save = spapr_pci_pre_save,
>      .post_load = spapr_pci_post_load,
>      .fields = (VMStateField[]) {
>          VMSTATE_UINT64_EQUAL(buid, sPAPRPHBState),
> -        VMSTATE_UNUSED_TEST(version_before_3,
> -                            sizeof(uint32_t) /* dma_liobn[0] */
> -                            + sizeof(uint64_t) /* mem_win_addr */
> -                            + sizeof(uint64_t) /* mem_win_size */
> -                            + sizeof(uint64_t) /* io_win_addr */
> -                            + sizeof(uint64_t) /* io_win_size */),
> +        VMSTATE_UINT32_EQUAL(dma_liobn[0], sPAPRPHBState),
> +        VMSTATE_UINT64_EQUAL(mem_win_addr, sPAPRPHBState),
> +        VMSTATE_UINT64_EQUAL(mem_win_size, sPAPRPHBState),
> +        VMSTATE_UINT64_EQUAL(io_win_addr, sPAPRPHBState),
> +        VMSTATE_UINT64_EQUAL(io_win_size, sPAPRPHBState),
>          VMSTATE_STRUCT_ARRAY(lsi_table, sPAPRPHBState, PCI_NUM_PINS, 0,
>                               vmstate_spapr_pci_lsi, struct spapr_pci_lsi),
>          VMSTATE_INT32(msi_devs_num, sPAPRPHBState),
> 

Reviewed-by: Thomas Huth <thuth@redhat.com>