[Xen-devel] [PATCH 2/3] x86/mm: Consolidate all Xen L2 slot writing into init_xen_pae_l2_slots()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Having all of this logic together makes it easier to follow Xen's virtual
setup across the whole system.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Tim Deegan <tim@xxxxxxx>
CC: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
CC: Julien Grall <julien.grall@xxxxxxx>
---
 xen/arch/x86/mm.c              | 16 +++++++++-------
 xen/arch/x86/mm/shadow/multi.c | 42 +++++++++++++++---------------------------
 xen/include/asm-x86/mm.h       |  1 +
 3 files changed, 25 insertions(+), 34 deletions(-)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index f90a42a..ea4af16 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -1433,13 +1433,7 @@ static int alloc_l2_table(struct page_info *page, 
unsigned long type,
     }
 
     if ( rc >= 0 && (type & PGT_pae_xen_l2) )
-    {
-        /* Xen private mappings. */
-        memcpy(&pl2e[COMPAT_L2_PAGETABLE_FIRST_XEN_SLOT(d)],
-               &compat_idle_pg_table_l2[
-                   l2_table_offset(HIRO_COMPAT_MPT_VIRT_START)],
-               COMPAT_L2_PAGETABLE_XEN_SLOTS(d) * sizeof(*pl2e));
-    }
+        init_xen_pae_l2_slots(pl2e, d);
 
     unmap_domain_page(pl2e);
     return rc > 0 ? 0 : rc;
@@ -1518,6 +1512,14 @@ static int alloc_l3_table(struct page_info *page)
     return rc > 0 ? 0 : rc;
 }
 
+void init_xen_pae_l2_slots(l2_pgentry_t *l2t, const struct domain *d)
+{
+    memcpy(&l2t[COMPAT_L2_PAGETABLE_FIRST_XEN_SLOT(d)],
+           &compat_idle_pg_table_l2[
+               l2_table_offset(HIRO_COMPAT_MPT_VIRT_START)],
+           COMPAT_L2_PAGETABLE_XEN_SLOTS(d) * sizeof(*l2t));
+}
+
 /*
  * This function must write all ROOT_PAGETABLE_PV_XEN_SLOTS, to clobber any
  * values a guest may have left there from alloc_l4_table().
diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
index d540af1..1b76e0c 100644
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -1521,31 +1521,6 @@ void sh_install_xen_entries_in_l4(struct domain *d, 
mfn_t gl4mfn, mfn_t sl4mfn)
 }
 #endif
 
-#if GUEST_PAGING_LEVELS >= 3
-// For 3-on-3 PV guests, we need to make sure the xen mappings are in
-// place, which means that we need to populate the l2h entry in the l3
-// table.
-
-static void sh_install_xen_entries_in_l2h(struct domain *d, mfn_t sl2hmfn)
-{
-    shadow_l2e_t *sl2e;
-
-    if ( !is_pv_32bit_domain(d) )
-        return;
-
-    sl2e = map_domain_page(sl2hmfn);
-    BUILD_BUG_ON(sizeof (l2_pgentry_t) != sizeof (shadow_l2e_t));
-
-    /* Copy the common Xen mappings from the idle domain */
-    memcpy(
-        &sl2e[COMPAT_L2_PAGETABLE_FIRST_XEN_SLOT(d)],
-        &compat_idle_pg_table_l2[l2_table_offset(HIRO_COMPAT_MPT_VIRT_START)],
-        COMPAT_L2_PAGETABLE_XEN_SLOTS(d) * sizeof(*sl2e));
-
-    unmap_domain_page(sl2e);
-}
-#endif
-
 
 /**************************************************************************/
 /* Create a shadow of a given guest page.
@@ -1610,7 +1585,14 @@ sh_make_shadow(struct vcpu *v, mfn_t gmfn, u32 
shadow_type)
 #endif
 #if GUEST_PAGING_LEVELS >= 3
         case SH_type_l2h_shadow:
-            sh_install_xen_entries_in_l2h(v->domain, smfn);
+            BUILD_BUG_ON(sizeof(l2_pgentry_t) != sizeof(shadow_l2e_t));
+            if ( is_pv_32bit_domain(d) )
+            {
+                shadow_l2e_t *l2t = map_domain_page(smfn);
+
+                init_xen_pae_l2_slots(l2t, d);
+                unmap_domain_page(l2t);
+            }
             break;
 #endif
         default: /* Do nothing */ break;
@@ -1677,6 +1659,8 @@ sh_make_monitor_table(struct vcpu *v)
 
             if ( is_pv_32bit_domain(d) )
             {
+                l2_pgentry_t *l2t;
+
                 /* For 32-bit PV guests, we need to map the 32-bit Xen
                  * area into its usual VAs in the monitor tables */
                 m3mfn = shadow_alloc(d, SH_type_monitor_table, 0);
@@ -1687,7 +1671,11 @@ sh_make_monitor_table(struct vcpu *v)
                 mfn_to_page(m2mfn)->shadow_flags = 2;
                 l3e = map_domain_page(m3mfn);
                 l3e[3] = l3e_from_mfn(m2mfn, _PAGE_PRESENT);
-                sh_install_xen_entries_in_l2h(d, m2mfn);
+
+                l2t = map_domain_page(m2mfn);
+                init_xen_pae_l2_slots(l2t, d);
+                unmap_domain_page(l2t);
+
                 unmap_domain_page(l3e);
             }
 
diff --git a/xen/include/asm-x86/mm.h b/xen/include/asm-x86/mm.h
index eeac4d7..da3c5e2 100644
--- a/xen/include/asm-x86/mm.h
+++ b/xen/include/asm-x86/mm.h
@@ -340,6 +340,7 @@ static inline void *__page_to_virt(const struct page_info 
*pg)
 int free_page_type(struct page_info *page, unsigned long type,
                    int preemptible);
 
+void init_xen_pae_l2_slots(l2_pgentry_t *l2t, const struct domain *d);
 void init_guest_l4_table(l4_pgentry_t[], const struct domain *,
                          bool_t zap_ro_mpt);
 bool fill_ro_mpt(mfn_t mfn);
-- 
2.1.4


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