Re: [Qemu-devel] [PATCH] mptsas: really fix migration compatibility

[Cao jin <caoj.fnst@cn.fujitsu.com>]

On 08/02/2016 06:34 PM, Paolo Bonzini wrote:
> Commit 2e2aa316 removed internal flag msi_in_use, but it
> existed in vmstate.  Restore it for migration to older QEMU
> versions.
>
> Reported-by: Amit Shah <amit.shah@redhat.com>
> Suggested-by: Amit Shah <amit.shah@redhat.com>
> Cc: Markus Armbruster <armbru@redhat.com>
> Cc: Marcel Apfelbaum <marcel@redhat.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Amit Shah <amit.shah@redhat.com>
> Cc: Cao jin <caoj.fnst@cn.fujitsu.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>   hw/scsi/mptsas.c | 4 +++-
>   hw/scsi/mptsas.h | 2 ++
>   2 files changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/hw/scsi/mptsas.c b/hw/scsi/mptsas.c
> index bebe513..0e0a22f 100644
> --- a/hw/scsi/mptsas.c
> +++ b/hw/scsi/mptsas.c
> @@ -1295,6 +1295,8 @@ static void mptsas_scsi_init(PCIDevice *dev, Error **errp)
>           /* With msi=auto, we fall back to MSI off silently */
>           error_free(err);
>
> +        /* Only used for migration.  */
> +        s->msi_in_use = (ret == 0);
>       }
>
>       memory_region_init_io(&s->mmio_io, OBJECT(s), &mptsas_mmio_ops, s,
> @@ -1370,7 +1372,7 @@ static const VMStateDescription vmstate_mptsas = {
>       .post_load = mptsas_post_load,
>       .fields      = (VMStateField[]) {
>           VMSTATE_PCI_DEVICE(dev, MPTSASState),
> -        VMSTATE_UNUSED(sizeof(bool)), /* Was msi_in_use */
> +        VMSTATE_BOOL(msi_in_use, MPTSASState),
>           VMSTATE_UINT32(state, MPTSASState),
>           VMSTATE_UINT8(who_init, MPTSASState),
>           VMSTATE_UINT8(doorbell_state, MPTSASState),
> diff --git a/hw/scsi/mptsas.h b/hw/scsi/mptsas.h
> index da014a3..0436a33 100644
> --- a/hw/scsi/mptsas.h
> +++ b/hw/scsi/mptsas.h
> @@ -31,6 +31,8 @@ struct MPTSASState {
>       OnOffAuto msi;
>       uint64_t sas_addr;
>
> +    bool msi_in_use;
> +
>       /* Doorbell register */
>       uint32_t state;
>       uint8_t who_init;
>

Thanks for saving my mistake.
Just FYI: there is a superfluous newline in mptsas_scsi_init() made by 
me, maybe is handy to remove.
-- 
Yours Sincerely,

Cao jin