x86: consolidate initialization of PV guest L4 page tables

So far this has been repeated in 3 places, requiring to remember to
update all of them if a change is being made.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

1 files changed, 13 insertions, 9 deletions

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 9627b076c6..d63ea250f5 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -1315,6 +1315,18 @@ static int alloc_l3_table(struct page_info *page, int preemptible)
     return rc > 0 ? 0 : rc;
 }
 
+void init_guest_l4_table(l4_pgentry_t l4tab[], const struct domain *d)
+{
+    /* Xen private mappings. */
+    memcpy(&l4tab[ROOT_PAGETABLE_FIRST_XEN_SLOT],
+           &idle_pg_table[ROOT_PAGETABLE_FIRST_XEN_SLOT],
+           ROOT_PAGETABLE_XEN_SLOTS * sizeof(l4_pgentry_t));
+    l4tab[l4_table_offset(LINEAR_PT_VIRT_START)] =
+        l4e_from_pfn(virt_to_mfn(l4tab), __PAGE_HYPERVISOR);
+    l4tab[l4_table_offset(PERDOMAIN_VIRT_START)] =
+        l4e_from_pfn(virt_to_mfn(d->arch.mm_perdomain_l3), __PAGE_HYPERVISOR);
+}
+
 static int alloc_l4_table(struct page_info *page, int preemptible)
 {
     struct domain *d = page_get_owner(page);
@@ -1358,15 +1370,7 @@ static int alloc_l4_table(struct page_info *page, int preemptible)
         adjust_guest_l4e(pl4e[i], d);
     }
 
-    /* Xen private mappings. */
-    memcpy(&pl4e[ROOT_PAGETABLE_FIRST_XEN_SLOT],
-           &idle_pg_table[ROOT_PAGETABLE_FIRST_XEN_SLOT],
-           ROOT_PAGETABLE_XEN_SLOTS * sizeof(l4_pgentry_t));
-    pl4e[l4_table_offset(LINEAR_PT_VIRT_START)] =
-        l4e_from_pfn(pfn, __PAGE_HYPERVISOR);
-    pl4e[l4_table_offset(PERDOMAIN_VIRT_START)] =
-        l4e_from_page(virt_to_page(d->arch.mm_perdomain_l3),
-                      __PAGE_HYPERVISOR);
+    init_guest_l4_table(pl4e, d);
 
     return rc > 0 ? 0 : rc;
 }