Commit 8e03e831 authored by Claudio Imbrenda's avatar Claudio Imbrenda
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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: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
parent 2db149a0

arch/s390/kvm/dat.c

+223 −0
Original line number Diff line number Diff line
@@ -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);

}

arch/s390/kvm/dat.h

+7 −0
Original line number Diff line number Diff line
@@ -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);