Re: [Qemu-devel] [PATCH v3 3/7] vmxnet3: Introduce 'x-old-msi-offsets' backword compatability property

[Jason Wang <jasowang@redhat.com>]

On 12/12/2015 08:00 PM, Shmulik Ladkani wrote:
> Following the previous patches, where vmxnet3's pci's msi/msix
> capability offsets and msix's PBA table offsets have been changed, this
> patch introduces a boolean property 'x-old-msi-offsets' to vmxnet3,
> whose default is false.
>
> Setting 'x-old-msi-offsets' to 'on' preserves the old offsets behavior,
> which allows migration to older versions.
>
> Signed-off-by: Shmulik Ladkani <shmulik.ladkani@ravellosystems.com>
> ---
>  hw/net/vmxnet3.c    | 2 ++
>  include/hw/compat.h | 4 ++++
>  2 files changed, 6 insertions(+)
>
> diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c
> index 97f0aea..d1fe888 100644
> --- a/hw/net/vmxnet3.c
> +++ b/hw/net/vmxnet3.c
> @@ -2564,6 +2564,8 @@ static const VMStateDescription vmstate_vmxnet3 = {
>  
>  static Property vmxnet3_properties[] = {
>      DEFINE_NIC_PROPERTIES(VMXNET3State, conf),
> +    DEFINE_PROP_BIT("x-old-msi-offsets", VMXNET3State, compat_flags,
> +                    VMXNET3_COMPAT_FLAG_OLD_MSI_OFFSETS_BIT, false),
>      DEFINE_PROP_END_OF_LIST(),
>  };
>  
> diff --git a/include/hw/compat.h b/include/hw/compat.h
> index d0b1c4f..01e326d 100644
> --- a/include/hw/compat.h
> +++ b/include/hw/compat.h
> @@ -18,6 +18,10 @@
>              .driver   = "virtio-pci",\
>              .property = "migrate-extra",\
>              .value    = "off",\
> +        },{\
> +            .driver   = "vmxnet3",\
> +            .property = "x-old-msi-offsets",\
> +            .value    = "on",\
>          },
>  
>  #define HW_COMPAT_2_3 \

Too late for 2.5. Need to do this for 2.6, so we probably want either
introduce 2.6 machine type by yourself or wait for somebody else to do
it and do it for HW_COMPAT_2_5 :)