Commit 9fcf93b5 authored by Jason J. Herne's avatar Jason J. Herne Committed by Christian Borntraeger
Browse files

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: default avatarJason J. Herne <jjherne@linux.vnet.ibm.com>
Reviewed-by: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent da00fcbd

arch/s390/include/asm/pgalloc.h

+1 −0
Original line number Diff line number Diff line
@@ -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)

{

arch/s390/mm/pgtable.c

+39 −0
Original line number Diff line number Diff line
@@ -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)

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