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KVM: S390: Create helper function get_guest_storage_key 

Define get_guest_storage_key which can be used to get the value of a guest
storage key. This compliments the functionality provided by the helper function
set_guest_storage_key. Both functions are needed for live migration of s390
guests that use storage keys.

Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
hifive-unleashed-5.1
Jason J. Herne 2014-09-23 09:18:57 -04:00 committed by Christian Borntraeger
parent da00fcbdac
commit 9fcf93b5de
2 changed files with 40 additions and 0 deletions
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1
arch/s390/include/asm/pgalloc.h
View File

@ -26,6 +26,7 @@ void page_table_reset_pgste(struct mm_struct *, unsigned long, unsigned long,
bool init_skey);
int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
unsigned long key, bool nq);
unsigned long get_guest_storage_key(struct mm_struct *mm, unsigned long addr);
static inline void clear_table(unsigned long *s, unsigned long val, size_t n)
{

39
arch/s390/mm/pgtable.c
View File

@ -980,6 +980,45 @@ retry:
}
EXPORT_SYMBOL(set_guest_storage_key);
unsigned long get_guest_storage_key(struct mm_struct *mm, unsigned long addr)
{
spinlock_t *ptl;
pgste_t pgste;
pte_t *ptep;
uint64_t physaddr;
unsigned long key = 0;
down_read(&mm->mmap_sem);
ptep = get_locked_pte(mm, addr, &ptl);
if (unlikely(!ptep)) {
up_read(&mm->mmap_sem);
return -EFAULT;
}
pgste = pgste_get_lock(ptep);
if (pte_val(*ptep) & _PAGE_INVALID) {
key |= (pgste_val(pgste) & PGSTE_ACC_BITS) >> 56;
key |= (pgste_val(pgste) & PGSTE_FP_BIT) >> 56;
key |= (pgste_val(pgste) & PGSTE_GR_BIT) >> 48;
key |= (pgste_val(pgste) & PGSTE_GC_BIT) >> 48;
} else {
physaddr = pte_val(*ptep) & PAGE_MASK;
key = page_get_storage_key(physaddr);
/* Reflect guest's logical view, not physical */
if (pgste_val(pgste) & PGSTE_GR_BIT)
key |= _PAGE_REFERENCED;
if (pgste_val(pgste) & PGSTE_GC_BIT)
key |= _PAGE_CHANGED;
}
pgste_set_unlock(ptep, pgste);
pte_unmap_unlock(ptep, ptl);
up_read(&mm->mmap_sem);
return key;
}
EXPORT_SYMBOL(get_guest_storage_key);
#else /* CONFIG_PGSTE */
static inline int page_table_with_pgste(struct page *page)