KVM: s390: KVM page table management functions: storage keys

Add page table management functions to be used for KVM guest (gmap)
page tables.

This patch adds functions related to storage key handling.

Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>

diff --git a/arch/s390/kvm/dat.c b/arch/s390/kvm/dat.c
index c31838107752c4cd515d4e3a5ba1c3c8f4027e5b..99682792d9ee5421af5639c080cd0ae827dab579 100644 (file)
--- a/arch/s390/kvm/dat.c
+++ b/arch/s390/kvm/dat.c
@@ -602,3 +602,226 @@ long _dat_walk_gfn_range(gfn_t start, gfn_t end, union asce asce,
 
        return dat_crste_walk_range(start, min(end, asce_end(asce)), table, &walk);
 }
+
+int dat_get_storage_key(union asce asce, gfn_t gfn, union skey *skey)
+{
+       union crste *crstep;
+       union pgste pgste;
+       union pte *ptep;
+       int rc;
+
+       skey->skey = 0;
+       rc = dat_entry_walk(NULL, gfn, asce, DAT_WALK_ANY, TABLE_TYPE_PAGE_TABLE, &crstep, &ptep);
+       if (rc)
+               return rc;
+
+       if (!ptep) {
+               union crste crste;
+
+               crste = READ_ONCE(*crstep);
+               if (!crste.h.fc || !crste.s.fc1.pr)
+                       return 0;
+               skey->skey = page_get_storage_key(large_crste_to_phys(crste, gfn));
+               return 0;
+       }
+       pgste = pgste_get_lock(ptep);
+       if (ptep->h.i) {
+               skey->acc = pgste.acc;
+               skey->fp = pgste.fp;
+       } else {
+               skey->skey = page_get_storage_key(pte_origin(*ptep));
+       }
+       skey->r |= pgste.gr;
+       skey->c |= pgste.gc;
+       pgste_set_unlock(ptep, pgste);
+       return 0;
+}
+
+static void dat_update_ptep_sd(union pgste old, union pgste pgste, union pte *ptep)
+{
+       if (pgste.acc != old.acc || pgste.fp != old.fp || pgste.gr != old.gr || pgste.gc != old.gc)
+               __atomic64_or(_PAGE_SD, &ptep->val);
+}
+
+int dat_set_storage_key(struct kvm_s390_mmu_cache *mc, union asce asce, gfn_t gfn,
+                       union skey skey, bool nq)
+{
+       union pgste pgste, old;
+       union crste *crstep;
+       union pte *ptep;
+       int rc;
+
+       rc = dat_entry_walk(mc, gfn, asce, DAT_WALK_LEAF_ALLOC, TABLE_TYPE_PAGE_TABLE,
+                           &crstep, &ptep);
+       if (rc)
+               return rc;
+
+       if (!ptep) {
+               page_set_storage_key(large_crste_to_phys(*crstep, gfn), skey.skey, !nq);
+               return 0;
+       }
+
+       old = pgste_get_lock(ptep);
+       pgste = old;
+
+       pgste.acc = skey.acc;
+       pgste.fp = skey.fp;
+       pgste.gc = skey.c;
+       pgste.gr = skey.r;
+
+       if (!ptep->h.i) {
+               union skey old_skey;
+
+               old_skey.skey = page_get_storage_key(pte_origin(*ptep));
+               pgste.hc |= old_skey.c;
+               pgste.hr |= old_skey.r;
+               old_skey.c = old.gc;
+               old_skey.r = old.gr;
+               skey.r = 0;
+               skey.c = 0;
+               page_set_storage_key(pte_origin(*ptep), skey.skey, !nq);
+       }
+
+       dat_update_ptep_sd(old, pgste, ptep);
+       pgste_set_unlock(ptep, pgste);
+       return 0;
+}
+
+static bool page_cond_set_storage_key(phys_addr_t paddr, union skey skey, union skey *oldkey,
+                                     bool nq, bool mr, bool mc)
+{
+       oldkey->skey = page_get_storage_key(paddr);
+       if (oldkey->acc == skey.acc && oldkey->fp == skey.fp &&
+           (oldkey->r == skey.r || mr) && (oldkey->c == skey.c || mc))
+               return false;
+       page_set_storage_key(paddr, skey.skey, !nq);
+       return true;
+}
+
+int dat_cond_set_storage_key(struct kvm_s390_mmu_cache *mmc, union asce asce, gfn_t gfn,
+                            union skey skey, union skey *oldkey, bool nq, bool mr, bool mc)
+{
+       union pgste pgste, old;
+       union crste *crstep;
+       union skey prev;
+       union pte *ptep;
+       int rc;
+
+       rc = dat_entry_walk(mmc, gfn, asce, DAT_WALK_LEAF_ALLOC, TABLE_TYPE_PAGE_TABLE,
+                           &crstep, &ptep);
+       if (rc)
+               return rc;
+
+       if (!ptep)
+               return page_cond_set_storage_key(large_crste_to_phys(*crstep, gfn), skey, oldkey,
+                                                nq, mr, mc);
+
+       old = pgste_get_lock(ptep);
+       pgste = old;
+
+       rc = 1;
+       pgste.acc = skey.acc;
+       pgste.fp = skey.fp;
+       pgste.gc = skey.c;
+       pgste.gr = skey.r;
+
+       if (!ptep->h.i) {
+               rc = page_cond_set_storage_key(pte_origin(*ptep), skey, &prev, nq, mr, mc);
+               pgste.hc |= prev.c;
+               pgste.hr |= prev.r;
+               prev.c |= old.gc;
+               prev.r |= old.gr;
+       } else {
+               prev.acc = old.acc;
+               prev.fp = old.fp;
+               prev.c = old.gc;
+               prev.r = old.gr;
+       }
+       if (oldkey)
+               *oldkey = prev;
+
+       dat_update_ptep_sd(old, pgste, ptep);
+       pgste_set_unlock(ptep, pgste);
+       return rc;
+}
+
+int dat_reset_reference_bit(union asce asce, gfn_t gfn)
+{
+       union pgste pgste, old;
+       union crste *crstep;
+       union pte *ptep;
+       int rc;
+
+       rc = dat_entry_walk(NULL, gfn, asce, DAT_WALK_ANY, TABLE_TYPE_PAGE_TABLE, &crstep, &ptep);
+       if (rc)
+               return rc;
+
+       if (!ptep) {
+               union crste crste = READ_ONCE(*crstep);
+
+               if (!crste.h.fc || !crste.s.fc1.pr)
+                       return 0;
+               return page_reset_referenced(large_crste_to_phys(*crstep, gfn));
+       }
+       old = pgste_get_lock(ptep);
+       pgste = old;
+
+       if (!ptep->h.i) {
+               rc = page_reset_referenced(pte_origin(*ptep));
+               pgste.hr = rc >> 1;
+       }
+       rc |= (pgste.gr << 1) | pgste.gc;
+       pgste.gr = 0;
+
+       dat_update_ptep_sd(old, pgste, ptep);
+       pgste_set_unlock(ptep, pgste);
+       return rc;
+}
+
+static long dat_reset_skeys_pte(union pte *ptep, gfn_t gfn, gfn_t next, struct dat_walk *walk)
+{
+       union pgste pgste;
+
+       pgste = pgste_get_lock(ptep);
+       pgste.acc = 0;
+       pgste.fp = 0;
+       pgste.gr = 0;
+       pgste.gc = 0;
+       if (ptep->s.pr)
+               page_set_storage_key(pte_origin(*ptep), PAGE_DEFAULT_KEY, 1);
+       pgste_set_unlock(ptep, pgste);
+
+       if (need_resched())
+               return next;
+       return 0;
+}
+
+static long dat_reset_skeys_crste(union crste *crstep, gfn_t gfn, gfn_t next, struct dat_walk *walk)
+{
+       phys_addr_t addr, end, origin = crste_origin_large(*crstep);
+
+       if (!crstep->h.fc || !crstep->s.fc1.pr)
+               return 0;
+
+       addr = ((max(gfn, walk->start) - gfn) << PAGE_SHIFT) + origin;
+       end = ((min(next, walk->end) - gfn) << PAGE_SHIFT) + origin;
+       while (ALIGN(addr + 1, _SEGMENT_SIZE) <= end)
+               addr = sske_frame(addr, PAGE_DEFAULT_KEY);
+       for ( ; addr < end; addr += PAGE_SIZE)
+               page_set_storage_key(addr, PAGE_DEFAULT_KEY, 1);
+
+       if (need_resched())
+               return next;
+       return 0;
+}
+
+long dat_reset_skeys(union asce asce, gfn_t start)
+{
+       const struct dat_walk_ops ops = {
+               .pte_entry = dat_reset_skeys_pte,
+               .pmd_entry = dat_reset_skeys_crste,
+               .pud_entry = dat_reset_skeys_crste,
+       };
+
+       return _dat_walk_gfn_range(start, asce_end(asce), asce, &ops, DAT_WALK_IGN_HOLES, NULL);
+}

diff --git a/arch/s390/kvm/dat.h b/arch/s390/kvm/dat.h
index 409064bd20a5cc38a5a079006f0cdba053e27d46..6c7815d4f07f99c4204dbc615abee3eec0752df6 100644 (file)
--- a/arch/s390/kvm/dat.h
+++ b/arch/s390/kvm/dat.h
@@ -472,6 +472,13 @@ int dat_entry_walk(struct kvm_s390_mmu_cache *mc, gfn_t gfn, union asce asce, in
                   int walk_level, union crste **last, union pte **ptepp);
 void dat_free_level(struct crst_table *table, bool owns_ptes);
 struct crst_table *dat_alloc_crst_sleepable(unsigned long init);
+int dat_get_storage_key(union asce asce, gfn_t gfn, union skey *skey);
+int dat_set_storage_key(struct kvm_s390_mmu_cache *mc, union asce asce, gfn_t gfn,
+                       union skey skey, bool nq);
+int dat_cond_set_storage_key(struct kvm_s390_mmu_cache *mmc, union asce asce, gfn_t gfn,
+                            union skey skey, union skey *oldkey, bool nq, bool mr, bool mc);
+int dat_reset_reference_bit(union asce asce, gfn_t gfn);
+long dat_reset_skeys(union asce asce, gfn_t start);
 
 int kvm_s390_mmu_cache_topup(struct kvm_s390_mmu_cache *mc);