s390/kvm: Add PGSTE manipulation functions
Add PGSTE manipulation functions:
* set_pgste_bits sets specific bits in a PGSTE
* get_pgste returns the whole PGSTE
* pgste_perform_essa manipulates a PGSTE to set specific storage states
* ESSA_[SG]ET_* macros used to indicate the action for manipulate_pgste
Signed-off-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Reviewed-by: Janosch Frank <frankja@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 463e5ef..947b66a 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -23,6 +23,7 @@
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
+#include <asm/page-states.h>
static inline pte_t ptep_flush_direct(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
@@ -787,4 +788,156 @@ int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
return 0;
}
EXPORT_SYMBOL(get_guest_storage_key);
+
+/**
+ * pgste_perform_essa - perform ESSA actions on the PGSTE.
+ * @mm: the memory context. It must have PGSTEs, no check is performed here!
+ * @hva: the host virtual address of the page whose PGSTE is to be processed
+ * @orc: the specific action to perform, see the ESSA_SET_* macros.
+ * @oldpte: the PTE will be saved there if the pointer is not NULL.
+ * @oldpgste: the old PGSTE will be saved there if the pointer is not NULL.
+ *
+ * Return: 1 if the page is to be added to the CBRL, otherwise 0,
+ * or < 0 in case of error. -EINVAL is returned for invalid values
+ * of orc, -EFAULT for invalid addresses.
+ */
+int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
+ unsigned long *oldpte, unsigned long *oldpgste)
+{
+ unsigned long pgstev;
+ spinlock_t *ptl;
+ pgste_t pgste;
+ pte_t *ptep;
+ int res = 0;
+
+ WARN_ON_ONCE(orc > ESSA_MAX);
+ if (unlikely(orc > ESSA_MAX))
+ return -EINVAL;
+ ptep = get_locked_pte(mm, hva, &ptl);
+ if (unlikely(!ptep))
+ return -EFAULT;
+ pgste = pgste_get_lock(ptep);
+ pgstev = pgste_val(pgste);
+ if (oldpte)
+ *oldpte = pte_val(*ptep);
+ if (oldpgste)
+ *oldpgste = pgstev;
+
+ switch (orc) {
+ case ESSA_GET_STATE:
+ break;
+ case ESSA_SET_STABLE:
+ pgstev &= ~_PGSTE_GPS_USAGE_MASK;
+ pgstev |= _PGSTE_GPS_USAGE_STABLE;
+ break;
+ case ESSA_SET_UNUSED:
+ pgstev &= ~_PGSTE_GPS_USAGE_MASK;
+ pgstev |= _PGSTE_GPS_USAGE_UNUSED;
+ if (pte_val(*ptep) & _PAGE_INVALID)
+ res = 1;
+ break;
+ case ESSA_SET_VOLATILE:
+ pgstev &= ~_PGSTE_GPS_USAGE_MASK;
+ pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
+ if (pte_val(*ptep) & _PAGE_INVALID)
+ res = 1;
+ break;
+ case ESSA_SET_POT_VOLATILE:
+ pgstev &= ~_PGSTE_GPS_USAGE_MASK;
+ if (!(pte_val(*ptep) & _PAGE_INVALID)) {
+ pgstev |= _PGSTE_GPS_USAGE_POT_VOLATILE;
+ break;
+ }
+ if (pgstev & _PGSTE_GPS_ZERO) {
+ pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
+ break;
+ }
+ if (!(pgstev & PGSTE_GC_BIT)) {
+ pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
+ res = 1;
+ break;
+ }
+ break;
+ case ESSA_SET_STABLE_RESIDENT:
+ pgstev &= ~_PGSTE_GPS_USAGE_MASK;
+ pgstev |= _PGSTE_GPS_USAGE_STABLE;
+ /*
+ * Since the resident state can go away any time after this
+ * call, we will not make this page resident. We can revisit
+ * this decision if a guest will ever start using this.
+ */
+ break;
+ case ESSA_SET_STABLE_IF_RESIDENT:
+ if (!(pte_val(*ptep) & _PAGE_INVALID)) {
+ pgstev &= ~_PGSTE_GPS_USAGE_MASK;
+ pgstev |= _PGSTE_GPS_USAGE_STABLE;
+ }
+ break;
+ default:
+ /* we should never get here! */
+ break;
+ }
+ /* If we are discarding a page, set it to logical zero */
+ if (res)
+ pgstev |= _PGSTE_GPS_ZERO;
+
+ pgste_val(pgste) = pgstev;
+ pgste_set_unlock(ptep, pgste);
+ pte_unmap_unlock(ptep, ptl);
+ return res;
+}
+EXPORT_SYMBOL(pgste_perform_essa);
+
+/**
+ * set_pgste_bits - set specific PGSTE bits.
+ * @mm: the memory context. It must have PGSTEs, no check is performed here!
+ * @hva: the host virtual address of the page whose PGSTE is to be processed
+ * @bits: a bitmask representing the bits that will be touched
+ * @value: the values of the bits to be written. Only the bits in the mask
+ * will be written.
+ *
+ * Return: 0 on success, < 0 in case of error.
+ */
+int set_pgste_bits(struct mm_struct *mm, unsigned long hva,
+ unsigned long bits, unsigned long value)
+{
+ spinlock_t *ptl;
+ pgste_t new;
+ pte_t *ptep;
+
+ ptep = get_locked_pte(mm, hva, &ptl);
+ if (unlikely(!ptep))
+ return -EFAULT;
+ new = pgste_get_lock(ptep);
+
+ pgste_val(new) &= ~bits;
+ pgste_val(new) |= value & bits;
+
+ pgste_set_unlock(ptep, new);
+ pte_unmap_unlock(ptep, ptl);
+ return 0;
+}
+EXPORT_SYMBOL(set_pgste_bits);
+
+/**
+ * get_pgste - get the current PGSTE for the given address.
+ * @mm: the memory context. It must have PGSTEs, no check is performed here!
+ * @hva: the host virtual address of the page whose PGSTE is to be processed
+ * @pgstep: will be written with the current PGSTE for the given address.
+ *
+ * Return: 0 on success, < 0 in case of error.
+ */
+int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep)
+{
+ spinlock_t *ptl;
+ pte_t *ptep;
+
+ ptep = get_locked_pte(mm, hva, &ptl);
+ if (unlikely(!ptep))
+ return -EFAULT;
+ *pgstep = pgste_val(pgste_get(ptep));
+ pte_unmap_unlock(ptep, ptl);
+ return 0;
+}
+EXPORT_SYMBOL(get_pgste);
#endif