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>
This commit is contained in:
Claudio Imbrenda 2026-02-04 16:02:45 +01:00
parent 2db149a0a6
commit 8e03e8316e
2 changed files with 230 additions and 0 deletions

View File

@ -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);
}

View File

@ -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);