Re: [Qemu-devel] [PATCH 0/3] decouple VIRTIO_BLK_F_SCSI from SG_IO support

[Paolo Bonzini <pbonzini@redhat.com>]

Il 07/03/2012 19:01, Paolo Bonzini ha scritto:
> VIRTIO_BLK_F_SCSI is supposed to mean whether the host can *parse*
> SCSI requests, not *execute* them.  So it should always be enabled,
> and the scsi=on/off property tied to a separate configuration variable
> that is not guest visible.
> 
> With this change, Linux has problems understanding failed requests, so
> patch 1 works around the Linux bugs.
> 
> Important: because we need to do this to fix a migration compatibility
> problem when QEMU might be invoked with an old machine type, we must do
> this unconditionally.  This more or less assumes that no one ever invoked
> QEMU with scsi=off, as it breaks migration from new QEMU, scsi=off to
> old QEMU, also scsi=off.  However new->old is not supported upstream.
> If any downstream cares about new->old migration, they can apply v1 of
> the patches instead of this.
> 
> Paolo Bonzini (3):
>   virtio-blk: report non-zero status when failing SG_IO requests
>   virtio-blk: define VirtIOBlkConf
>   virtio-blk: always enable VIRTIO_BLK_F_SCSI
> 
>  hw/s390-virtio-bus.c |   10 ++++--
>  hw/s390-virtio-bus.h |    4 +-
>  hw/virtio-blk.c      |   77 ++++++++++++++++++++++++-------------------------
>  hw/virtio-blk.h      |   14 +++++----
>  hw/virtio-pci.c      |   11 ++++---
>  hw/virtio-pci.h      |    4 +-
>  hw/virtio.h          |    4 +-
>  7 files changed, 64 insertions(+), 60 deletions(-)
> 

Ping.

Paolo