Re: [PATCH 11/11] KVM: s390: expose no-DAT to guest and migration support

[Cornelia Huck <cohuck@redhat.com>]

On Mon, 28 Aug 2017 10:07:31 +0200
Christian Borntraeger <borntraeger@de.ibm.com> wrote:

> From: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
> 
> The STFLE bit 147 indicates whether the ESSA no-DAT operation code is
> valid, the bit is not normally provided to the host; the host is
> instead provided with an SCLP bit that indicates whether guests can
> support the feature.
> 
> This patch:
> * enables the STFLE bit in the guest if the corresponding SCLP bit is
>   present in the host.
> * adds support for migrating the no-DAT bit in the PGSTEs
> * fixes the software interpretation of the ESSA instruction that is
>   used when migrating, both for the new operation code and for the old
>   "set stable", as per specifications.
> 
> Signed-off-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
> Signed-off-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
>  arch/s390/include/asm/page-states.h | 2 +-
>  arch/s390/kvm/kvm-s390.c            | 8 ++++++--
>  arch/s390/kvm/priv.c                | 6 +++++-
>  arch/s390/mm/pgtable.c              | 6 +++++-
>  4 files changed, 17 insertions(+), 5 deletions(-)

This is a bit hard to review without the previous patches (I had to
hunt down MACHINE_HAS_TLB_GUEST, for example), and it seems much if not
all of this is not externally documented... but it seems consistent and
reasonable, so

Acked-by: Cornelia Huck <cohuck@redhat.com>