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KVM: s390: handle missing storage-key facility

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Without the storage-key facility, SIE won't interpret SSKE, ISKE and
RRBE for us. So let's add proper interception handlers that will be called
if lazy sske cannot be enabled.

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
David Hildenbrand
2016-05-10 09:50:21 +02:00
committed by Christian Borntraeger
parent 11ddcd41bc
commit a7e19ab55f
4 changed files with 184 additions and 11 deletions
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37
arch/s390/mm/pgtable.c
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@@ -572,6 +572,43 @@ int cond_set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
}
EXPORT_SYMBOL(cond_set_guest_storage_key);
/**
* Reset a guest reference bit (rrbe), returning the reference and changed bit.
*
* Returns < 0 in case of error, otherwise the cc to be reported to the guest.
*/
int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
{
spinlock_t *ptl;
pgste_t old, new;
pte_t *ptep;
int cc = 0;
ptep = get_locked_pte(mm, addr, &ptl);
if (unlikely(!ptep))
return -EFAULT;
new = old = pgste_get_lock(ptep);
/* Reset guest reference bit only */
pgste_val(new) &= ~PGSTE_GR_BIT;
if (!(pte_val(*ptep) & _PAGE_INVALID)) {
cc = page_reset_referenced(pte_val(*ptep) & PAGE_MASK);
/* Merge real referenced bit into host-set */
pgste_val(new) |= ((unsigned long) cc << 53) & PGSTE_HR_BIT;
}
/* Reflect guest's logical view, not physical */
cc |= (pgste_val(old) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 49;
/* Changing the guest storage key is considered a change of the page */
if ((pgste_val(new) ^ pgste_val(old)) & PGSTE_GR_BIT)
pgste_val(new) |= PGSTE_UC_BIT;
pgste_set_unlock(ptep, new);
pte_unmap_unlock(ptep, ptl);
return 0;
}
EXPORT_SYMBOL(reset_guest_reference_bit);
int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
unsigned char *key)
{