/* SPDX-License-Identifier: GPL-2.0 */
/*
 *  KVM guest address space mapping code
 *
 *    Copyright IBM Corp. 2007, 2016, 2025
 *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
 *               Claudio Imbrenda <imbrenda@linux.ibm.com>
 */

#ifndef ARCH_KVM_S390_GMAP_H
#define ARCH_KVM_S390_GMAP_H

#include "dat.h"

/**
 * enum gmap_flags - Flags of a gmap.
 *
 * @GMAP_FLAG_SHADOW: The gmap is a vsie shadow gmap.
 * @GMAP_FLAG_OWNS_PAGETABLES: The gmap owns all dat levels; normally 1, is 0
 *                             only for ucontrol per-cpu gmaps, since they
 *                             share the page tables with the main gmap.
 * @GMAP_FLAG_IS_UCONTROL: The gmap is ucontrol (main gmap or per-cpu gmap).
 * @GMAP_FLAG_ALLOW_HPAGE_1M: 1M hugepages are allowed for this gmap,
 *                            independently of the page size used by userspace.
 * @GMAP_FLAG_ALLOW_HPAGE_2G: 2G hugepages are allowed for this gmap,
 *                            independently of the page size used by userspace.
 * @GMAP_FLAG_PFAULT_ENABLED: Pfault is enabled for the gmap.
 * @GMAP_FLAG_USES_SKEYS: If the guest uses storage keys.
 * @GMAP_FLAG_USES_CMM: Whether the guest uses CMMA.
 * @GMAP_FLAG_EXPORT_ON_UNMAP: Whether to export guest pages when unmapping.
 */
enum gmap_flags {
        GMAP_FLAG_SHADOW = 0,
        GMAP_FLAG_OWNS_PAGETABLES,
        GMAP_FLAG_IS_UCONTROL,
        GMAP_FLAG_ALLOW_HPAGE_1M,
        GMAP_FLAG_ALLOW_HPAGE_2G,
        GMAP_FLAG_PFAULT_ENABLED,
        GMAP_FLAG_USES_SKEYS,
        GMAP_FLAG_USES_CMM,
        GMAP_FLAG_EXPORT_ON_UNMAP,
};

/**
 * struct gmap_struct - Guest address space.
 *
 * @flags: GMAP_FLAG_* flags.
 * @edat_level: The edat level of this shadow gmap.
 * @kvm: The vm.
 * @asce: The ASCE used by this gmap.
 * @list: List head used in children gmaps for the children gmap list.
 * @children_lock: Protects children and scb_users.
 * @children: List of child gmaps of this gmap.
 * @scb_users: List of vsie_scb that use this shadow gmap.
 * @parent: Parent gmap of a child gmap.
 * @guest_asce: Original ASCE of this shadow gmap.
 * @host_to_rmap_lock: Protects host_to_rmap.
 * @host_to_rmap: Radix tree mapping host addresses to guest addresses.
 */
struct gmap {
        unsigned long flags;
        unsigned char edat_level;
        struct kvm *kvm;
        union asce asce;
        struct list_head list;
        spinlock_t children_lock;       /* Protects: children, scb_users */
        struct list_head children;
        struct list_head scb_users;
        struct gmap *parent;
        union asce guest_asce;
        spinlock_t host_to_rmap_lock;   /* Protects host_to_rmap */
        struct radix_tree_root host_to_rmap;
        refcount_t refcount;
};

struct gmap_cache {
        struct list_head list;
        struct gmap *gmap;
};

#define gmap_for_each_rmap_safe(pos, n, head) \
        for (pos = (head); n = pos ? pos->next : NULL, pos; pos = n)

int s390_replace_asce(struct gmap *gmap);
bool _gmap_unmap_prefix(struct gmap *gmap, gfn_t gfn, gfn_t end, bool hint);
bool gmap_age_gfn(struct gmap *gmap, gfn_t start, gfn_t end);
bool gmap_unmap_gfn_range(struct gmap *gmap, struct kvm_memory_slot *slot, gfn_t start, gfn_t end);
int gmap_try_fixup_minor(struct gmap *gmap, struct guest_fault *fault);
struct gmap *gmap_new(struct kvm *kvm, gfn_t limit);
struct gmap *gmap_new_child(struct gmap *parent, gfn_t limit);
void gmap_remove_child(struct gmap *child);
void gmap_dispose(struct gmap *gmap);
int gmap_link(struct kvm_s390_mmu_cache *mc, struct gmap *gmap, struct guest_fault *fault);
void gmap_sync_dirty_log(struct gmap *gmap, gfn_t start, gfn_t end);
int gmap_set_limit(struct gmap *gmap, gfn_t limit);
int gmap_ucas_translate(struct kvm_s390_mmu_cache *mc, struct gmap *gmap, gpa_t *gaddr);
int gmap_ucas_map(struct gmap *gmap, gfn_t p_gfn, gfn_t c_gfn, unsigned long count);
void gmap_ucas_unmap(struct gmap *gmap, gfn_t c_gfn, unsigned long count);
int gmap_enable_skeys(struct gmap *gmap);
int gmap_pv_destroy_range(struct gmap *gmap, gfn_t start, gfn_t end, bool interruptible);
int gmap_insert_rmap(struct gmap *sg, gfn_t p_gfn, gfn_t r_gfn, int level);
int gmap_protect_rmap(struct kvm_s390_mmu_cache *mc, struct gmap *sg, gfn_t p_gfn, gfn_t r_gfn,
                      kvm_pfn_t pfn, int level, bool wr);
void gmap_set_cmma_all_dirty(struct gmap *gmap);
void _gmap_handle_vsie_unshadow_event(struct gmap *parent, gfn_t gfn);
struct gmap *gmap_create_shadow(struct kvm_s390_mmu_cache *mc, struct gmap *gmap,
                                union asce asce, int edat_level);
void gmap_split_huge_pages(struct gmap *gmap);

static inline bool uses_skeys(struct gmap *gmap)
{
        return test_bit(GMAP_FLAG_USES_SKEYS, &gmap->flags);
}

static inline bool uses_cmm(struct gmap *gmap)
{
        return test_bit(GMAP_FLAG_USES_CMM, &gmap->flags);
}

static inline bool pfault_enabled(struct gmap *gmap)
{
        return test_bit(GMAP_FLAG_PFAULT_ENABLED, &gmap->flags);
}

static inline bool is_ucontrol(struct gmap *gmap)
{
        return test_bit(GMAP_FLAG_IS_UCONTROL, &gmap->flags);
}

static inline bool is_shadow(struct gmap *gmap)
{
        return test_bit(GMAP_FLAG_SHADOW, &gmap->flags);
}

static inline bool owns_page_tables(struct gmap *gmap)
{
        return test_bit(GMAP_FLAG_OWNS_PAGETABLES, &gmap->flags);
}

static inline struct gmap *gmap_put(struct gmap *gmap)
{
        if (refcount_dec_and_test(&gmap->refcount))
                gmap_dispose(gmap);
        return NULL;
}

static inline void gmap_get(struct gmap *gmap)
{
        WARN_ON_ONCE(unlikely(!refcount_inc_not_zero(&gmap->refcount)));
}

static inline void gmap_handle_vsie_unshadow_event(struct gmap *parent, gfn_t gfn)
{
        scoped_guard(spinlock, &parent->children_lock)
                _gmap_handle_vsie_unshadow_event(parent, gfn);
}

static inline bool gmap_mkold_prefix(struct gmap *gmap, gfn_t gfn, gfn_t end)
{
        return _gmap_unmap_prefix(gmap, gfn, end, true);
}

static inline bool gmap_unmap_prefix(struct gmap *gmap, gfn_t gfn, gfn_t end)
{
        return _gmap_unmap_prefix(gmap, gfn, end, false);
}

static inline union pgste _gmap_ptep_xchg(struct gmap *gmap, union pte *ptep, union pte newpte,
                                          union pgste pgste, gfn_t gfn, bool needs_lock)
{
        lockdep_assert_held(&gmap->kvm->mmu_lock);
        if (!needs_lock)
                lockdep_assert_held(&gmap->children_lock);
        else
                lockdep_assert_not_held(&gmap->children_lock);

        if (pgste.prefix_notif && (newpte.h.p || newpte.h.i)) {
                pgste.prefix_notif = 0;
                gmap_unmap_prefix(gmap, gfn, gfn + 1);
        }
        if (pgste.vsie_notif && (ptep->h.p != newpte.h.p || newpte.h.i)) {
                pgste.vsie_notif = 0;
                if (needs_lock)
                        gmap_handle_vsie_unshadow_event(gmap, gfn);
                else
                        _gmap_handle_vsie_unshadow_event(gmap, gfn);
        }
        if (!ptep->s.d && newpte.s.d && !newpte.s.s)
                SetPageDirty(pfn_to_page(newpte.h.pfra));
        return __dat_ptep_xchg(ptep, pgste, newpte, gfn, gmap->asce, uses_skeys(gmap));
}

static inline union pgste gmap_ptep_xchg(struct gmap *gmap, union pte *ptep, union pte newpte,
                                         union pgste pgste, gfn_t gfn)
{
        return _gmap_ptep_xchg(gmap, ptep, newpte, pgste, gfn, true);
}

static inline bool __must_check _gmap_crstep_xchg_atomic(struct gmap *gmap, union crste *crstep,
                                                         union crste oldcrste, union crste newcrste,
                                                         gfn_t gfn, bool needs_lock)
{
        unsigned long align = is_pmd(newcrste) ? _PAGE_ENTRIES : _PAGE_ENTRIES * _CRST_ENTRIES;

        if (KVM_BUG_ON(crstep->h.tt != oldcrste.h.tt || newcrste.h.tt != oldcrste.h.tt, gmap->kvm))
                return true;

        lockdep_assert_held(&gmap->kvm->mmu_lock);
        if (!needs_lock)
                lockdep_assert_held(&gmap->children_lock);

        gfn = ALIGN_DOWN(gfn, align);
        if (crste_prefix(oldcrste) && (newcrste.h.p || newcrste.h.i || !crste_prefix(newcrste))) {
                newcrste.s.fc1.prefix_notif = 0;
                gmap_unmap_prefix(gmap, gfn, gfn + align);
        }
        if (crste_leaf(oldcrste) && oldcrste.s.fc1.vsie_notif &&
            (newcrste.h.p || newcrste.h.i || !newcrste.s.fc1.vsie_notif)) {
                newcrste.s.fc1.vsie_notif = 0;
                if (needs_lock)
                        gmap_handle_vsie_unshadow_event(gmap, gfn);
                else
                        _gmap_handle_vsie_unshadow_event(gmap, gfn);
        }
        if (!oldcrste.s.fc1.d && newcrste.s.fc1.d && !newcrste.s.fc1.s)
                SetPageDirty(phys_to_page(crste_origin_large(newcrste)));
        return dat_crstep_xchg_atomic(crstep, oldcrste, newcrste, gfn, gmap->asce);
}

static inline bool __must_check gmap_crstep_xchg_atomic(struct gmap *gmap, union crste *crstep,
                                                        union crste oldcrste, union crste newcrste,
                                                        gfn_t gfn)
{
        return _gmap_crstep_xchg_atomic(gmap, crstep, oldcrste, newcrste, gfn, true);
}

/**
 * gmap_is_shadow_valid() - check if a shadow guest address space matches the
 *                          given properties and is still valid.
 * @sg: Pointer to the shadow guest address space structure.
 * @asce: ASCE for which the shadow table is requested.
 * @edat_level: Edat level to be used for the shadow translation.
 *
 * Return: true if the gmap shadow is still valid and matches the given
 * properties and the caller can continue using it; false otherwise, the
 * caller has to request a new shadow gmap in this case.
 */
static inline bool gmap_is_shadow_valid(struct gmap *sg, union asce asce, int edat_level)
{
        return sg->guest_asce.val == asce.val && sg->edat_level == edat_level;
}

#endif /* ARCH_KVM_S390_GMAP_H */