--- a/xen/arch/x86/mm/hap/hap.c
+++ b/xen/arch/x86/mm/hap/hap.c
@@ -823,6 +823,11 @@ hap_write_p2m_entry(struct p2m_domain *p
     return 0;
 }
 
+void hap_p2m_init(struct p2m_domain *p2m)
+{
+    p2m->write_p2m_entry = hap_write_p2m_entry;
+}
+
 static unsigned long hap_gva_to_gfn_real_mode(
     struct vcpu *v, struct p2m_domain *p2m, unsigned long gva, uint32_t *pfec)
 {
@@ -846,7 +851,6 @@ static const struct paging_mode hap_pagi
     .p2m_ga_to_gfn          = hap_p2m_ga_to_gfn_real_mode,
     .update_cr3             = hap_update_cr3,
     .update_paging_modes    = hap_update_paging_modes,
-    .write_p2m_entry        = hap_write_p2m_entry,
     .flush_tlb              = flush_tlb,
     .guest_levels           = 1
 };
@@ -858,7 +862,6 @@ static const struct paging_mode hap_pagi
     .p2m_ga_to_gfn          = hap_p2m_ga_to_gfn_2_levels,
     .update_cr3             = hap_update_cr3,
     .update_paging_modes    = hap_update_paging_modes,
-    .write_p2m_entry        = hap_write_p2m_entry,
     .flush_tlb              = flush_tlb,
     .guest_levels           = 2
 };
@@ -870,7 +873,6 @@ static const struct paging_mode hap_pagi
     .p2m_ga_to_gfn          = hap_p2m_ga_to_gfn_3_levels,
     .update_cr3             = hap_update_cr3,
     .update_paging_modes    = hap_update_paging_modes,
-    .write_p2m_entry        = hap_write_p2m_entry,
     .flush_tlb              = flush_tlb,
     .guest_levels           = 3
 };
@@ -882,7 +884,6 @@ static const struct paging_mode hap_pagi
     .p2m_ga_to_gfn          = hap_p2m_ga_to_gfn_4_levels,
     .update_cr3             = hap_update_cr3,
     .update_paging_modes    = hap_update_paging_modes,
-    .write_p2m_entry        = hap_write_p2m_entry,
     .flush_tlb              = flush_tlb,
     .guest_levels           = 4
 };
--- a/xen/arch/x86/mm/p2m-pt.c
+++ b/xen/arch/x86/mm/p2m-pt.c
@@ -126,8 +126,9 @@ static int write_p2m_entry(struct p2m_do
 
     if ( v->domain != d )
         v = d->vcpu ? d->vcpu[0] : NULL;
-    if ( likely(v && paging_mode_enabled(d) && paging_get_hostmode(v)) )
-        rc = paging_get_hostmode(v)->write_p2m_entry(p2m, gfn, p, new, level);
+    if ( likely(v && paging_mode_enabled(d) && paging_get_hostmode(v)) ||
+         p2m_is_nestedp2m(p2m) )
+        rc = p2m->write_p2m_entry(p2m, gfn, p, new, level);
     else
         safe_write_pte(p, new);
 
@@ -209,7 +210,7 @@ p2m_next_level(struct p2m_domain *p2m, v
 
         new_entry = l1e_from_mfn(mfn, P2M_BASE_FLAGS | _PAGE_RW);
 
-        rc = p2m->write_p2m_entry(p2m, gfn, p2m_entry, new_entry, level + 1);
+        rc = write_p2m_entry(p2m, gfn, p2m_entry, new_entry, level + 1);
         if ( rc )
             goto error;
     }
@@ -251,7 +252,7 @@ p2m_next_level(struct p2m_domain *p2m, v
         {
             new_entry = l1e_from_pfn(pfn | (i << ((level - 1) * PAGETABLE_ORDER)),
                                      flags);
-            rc = p2m->write_p2m_entry(p2m, gfn, l1_entry + i, new_entry, level);
+            rc = write_p2m_entry(p2m, gfn, l1_entry + i, new_entry, level);
             if ( rc )
             {
                 unmap_domain_page(l1_entry);
@@ -262,8 +263,7 @@ p2m_next_level(struct p2m_domain *p2m, v
         unmap_domain_page(l1_entry);
 
         new_entry = l1e_from_mfn(mfn, P2M_BASE_FLAGS | _PAGE_RW);
-        rc = p2m->write_p2m_entry(p2m, gfn, p2m_entry, new_entry,
-                                  level + 1);
+        rc = write_p2m_entry(p2m, gfn, p2m_entry, new_entry, level + 1);
         if ( rc )
             goto error;
     }
@@ -335,7 +335,7 @@ static int p2m_pt_set_recalc_range(struc
             if ( (l1e_get_flags(e) & _PAGE_PRESENT) && !needs_recalc(l1, e) )
             {
                 set_recalc(l1, e);
-                err = p2m->write_p2m_entry(p2m, first_gfn, pent, e, level);
+                err = write_p2m_entry(p2m, first_gfn, pent, e, level);
                 if ( err )
                 {
                     ASSERT_UNREACHABLE();
@@ -412,8 +412,8 @@ static int do_recalc(struct p2m_domain *
                      !needs_recalc(l1, ent) )
                 {
                     set_recalc(l1, ent);
-                    err = p2m->write_p2m_entry(p2m, gfn - remainder, &ptab[i],
-                                               ent, level);
+                    err = write_p2m_entry(p2m, gfn - remainder, &ptab[i], ent,
+                                          level);
                     if ( err )
                     {
                         ASSERT_UNREACHABLE();
@@ -426,7 +426,7 @@ static int do_recalc(struct p2m_domain *
             if ( !err )
             {
                 clear_recalc(l1, e);
-                err = p2m->write_p2m_entry(p2m, gfn, pent, e, level + 1);
+                err = write_p2m_entry(p2m, gfn, pent, e, level + 1);
                 ASSERT(!err);
 
                 recalc_done = true;
@@ -474,7 +474,7 @@ static int do_recalc(struct p2m_domain *
         }
         else
             clear_recalc(l1, e);
-        err = p2m->write_p2m_entry(p2m, gfn, pent, e, level + 1);
+        err = write_p2m_entry(p2m, gfn, pent, e, level + 1);
         ASSERT(!err);
 
         recalc_done = true;
@@ -618,7 +618,7 @@ p2m_pt_set_entry(struct p2m_domain *p2m,
             : l3e_empty();
         entry_content.l1 = l3e_content.l3;
 
-        rc = p2m->write_p2m_entry(p2m, gfn, p2m_entry, entry_content, 3);
+        rc = write_p2m_entry(p2m, gfn, p2m_entry, entry_content, 3);
         /* NB: write_p2m_entry() handles tlb flushes properly */
         if ( rc )
             goto out;
@@ -655,7 +655,7 @@ p2m_pt_set_entry(struct p2m_domain *p2m,
             entry_content = l1e_empty();
 
         /* level 1 entry */
-        rc = p2m->write_p2m_entry(p2m, gfn, p2m_entry, entry_content, 1);
+        rc = write_p2m_entry(p2m, gfn, p2m_entry, entry_content, 1);
         /* NB: write_p2m_entry() handles tlb flushes properly */
         if ( rc )
             goto out;
@@ -690,7 +690,7 @@ p2m_pt_set_entry(struct p2m_domain *p2m,
             : l2e_empty();
         entry_content.l1 = l2e_content.l2;
 
-        rc = p2m->write_p2m_entry(p2m, gfn, p2m_entry, entry_content, 2);
+        rc = write_p2m_entry(p2m, gfn, p2m_entry, entry_content, 2);
         /* NB: write_p2m_entry() handles tlb flushes properly */
         if ( rc )
             goto out;
@@ -914,7 +914,7 @@ static void p2m_pt_change_entry_type_glo
             int rc;
 
             set_recalc(l1, e);
-            rc = p2m->write_p2m_entry(p2m, gfn, &tab[i], e, 4);
+            rc = write_p2m_entry(p2m, gfn, &tab[i], e, 4);
             if ( rc )
             {
                 ASSERT_UNREACHABLE();
@@ -1132,7 +1132,13 @@ void p2m_pt_init(struct p2m_domain *p2m)
     p2m->recalc = do_recalc;
     p2m->change_entry_type_global = p2m_pt_change_entry_type_global;
     p2m->change_entry_type_range = p2m_pt_change_entry_type_range;
-    p2m->write_p2m_entry = write_p2m_entry;
+
+    /* Still too early to use paging_mode_hap(). */
+    if ( hap_enabled(p2m->domain) )
+        hap_p2m_init(p2m);
+    else if ( IS_ENABLED(CONFIG_SHADOW_PAGING) )
+        shadow_p2m_init(p2m);
+
 #if P2M_AUDIT
     p2m->audit_p2m = p2m_pt_audit_p2m;
 #else
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -3137,7 +3137,7 @@ static void sh_unshadow_for_p2m_change(s
     }
 }
 
-int
+static int
 shadow_write_p2m_entry(struct p2m_domain *p2m, unsigned long gfn,
                        l1_pgentry_t *p, l1_pgentry_t new,
                        unsigned int level)
@@ -3183,6 +3183,11 @@ shadow_write_p2m_entry(struct p2m_domain
     return 0;
 }
 
+void shadow_p2m_init(struct p2m_domain *p2m)
+{
+    p2m->write_p2m_entry = shadow_write_p2m_entry;
+}
+
 /**************************************************************************/
 /* Log-dirty mode support */
 
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -4792,7 +4792,6 @@ const struct paging_mode sh_paging_mode
     .gva_to_gfn                    = sh_gva_to_gfn,
     .update_cr3                    = sh_update_cr3,
     .update_paging_modes           = shadow_update_paging_modes,
-    .write_p2m_entry               = shadow_write_p2m_entry,
     .flush_tlb                     = shadow_flush_tlb,
     .guest_levels                  = GUEST_PAGING_LEVELS,
     .shadow.detach_old_tables      = sh_detach_old_tables,
--- a/xen/arch/x86/mm/shadow/none.c
+++ b/xen/arch/x86/mm/shadow/none.c
@@ -60,21 +60,12 @@ static void _update_paging_modes(struct
     ASSERT_UNREACHABLE();
 }
 
-static int _write_p2m_entry(struct p2m_domain *p2m, unsigned long gfn,
-                            l1_pgentry_t *p, l1_pgentry_t new,
-                            unsigned int level)
-{
-    ASSERT_UNREACHABLE();
-    return -EOPNOTSUPP;
-}
-
 static const struct paging_mode sh_paging_none = {
     .page_fault                    = _page_fault,
     .invlpg                        = _invlpg,
     .gva_to_gfn                    = _gva_to_gfn,
     .update_cr3                    = _update_cr3,
     .update_paging_modes           = _update_paging_modes,
-    .write_p2m_entry               = _write_p2m_entry,
 };
 
 void shadow_vcpu_init(struct vcpu *v)
--- a/xen/arch/x86/mm/shadow/private.h
+++ b/xen/arch/x86/mm/shadow/private.h
@@ -390,11 +390,6 @@ static inline int sh_remove_write_access
 }
 #endif
 
-/* Functions that atomically write PT/P2M entries and update state */
-int shadow_write_p2m_entry(struct p2m_domain *p2m, unsigned long gfn,
-                           l1_pgentry_t *p, l1_pgentry_t new,
-                           unsigned int level);
-
 /* Functions that atomically write PV guest PT entries */
 void sh_write_guest_entry(struct vcpu *v, intpte_t *p, intpte_t new,
                           mfn_t gmfn);
--- a/xen/include/asm-x86/p2m.h
+++ b/xen/include/asm-x86/p2m.h
@@ -836,6 +836,9 @@ void p2m_flush_nestedp2m(struct domain *
 /* Flushes the np2m specified by np2m_base (if it exists) */
 void np2m_flush_base(struct vcpu *v, unsigned long np2m_base);
 
+void hap_p2m_init(struct p2m_domain *p2m);
+void shadow_p2m_init(struct p2m_domain *p2m);
+
 int nestedp2m_write_p2m_entry(struct p2m_domain *p2m, unsigned long gfn,
     l1_pgentry_t *p, l1_pgentry_t new, unsigned int level);
 
--- a/xen/include/asm-x86/paging.h
+++ b/xen/include/asm-x86/paging.h
@@ -141,10 +141,6 @@ struct paging_mode {
     void          (*update_cr3            )(struct vcpu *v, int do_locking,
                                             bool noflush);
     void          (*update_paging_modes   )(struct vcpu *v);
-    int           (*write_p2m_entry       )(struct p2m_domain *p2m,
-                                            unsigned long gfn,
-                                            l1_pgentry_t *p, l1_pgentry_t new,
-                                            unsigned int level);
     bool          (*flush_tlb             )(bool (*flush_vcpu)(void *ctxt,
                                                                struct vcpu *v),
                                             void *ctxt);
