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KVM: s390: expose no-DAT to guest and migration support

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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>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
Claudio Imbrenda
2016-08-29 15:56:55 +02:00
committed by Christian Borntraeger
parent 631aebfee8
commit 1bab1c02af
4 changed files with 17 additions and 5 deletions
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6
arch/s390/mm/pgtable.c
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@ -919,7 +919,7 @@ int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
case ESSA_GET_STATE:
break;
case ESSA_SET_STABLE:
pgstev &= ~_PGSTE_GPS_USAGE_MASK;
pgstev &= ~(_PGSTE_GPS_USAGE_MASK | _PGSTE_GPS_NODAT);
pgstev |= _PGSTE_GPS_USAGE_STABLE;
break;
case ESSA_SET_UNUSED:
@ -965,6 +965,10 @@ int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
pgstev |= _PGSTE_GPS_USAGE_STABLE;
}
break;
case ESSA_SET_STABLE_NODAT:
pgstev &= ~_PGSTE_GPS_USAGE_MASK;
pgstev |= _PGSTE_GPS_USAGE_STABLE | _PGSTE_GPS_NODAT;
break;
default:
/* we should never get here! */
break;