x86/mm: Use a more descriptive name for pagetable mfns

In many places, a PTE being modified is accompanied by the pagetable
mfn which contains the PTE (primarily in order to be able to maintain
linear mapping counts).  In many cases, this mfn is stored in the
non-descript variable (or argement) "pfn".

Replace these names with lNmfn, to indicate that 1) this is a
pagetable mfn, and 2) that it is the same level as the PTE in
question.  This should be enough to remind readers that it's the mfn
containing the PTE.

No functional change.

Signed-off-by: George Dunlap <george.dunlap@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 9556e8f780209478b570cc09e94332b5549a293b..ceb656ca75a08034c12ecba56feaca413836d7e6 100644 (file)
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -1141,7 +1141,7 @@ static int get_page_and_type_from_mfn(
 define_get_linear_pagetable(l2);
 static int
 get_page_from_l2e(
-    l2_pgentry_t l2e, unsigned long pfn, struct domain *d, unsigned int flags)
+    l2_pgentry_t l2e, unsigned long l2mfn, struct domain *d, unsigned int flags)
 {
     unsigned long mfn = l2e_get_pfn(l2e);
     int rc;
@@ -1156,7 +1156,7 @@ get_page_from_l2e(
     ASSERT(!(flags & PTF_preemptible));
 
     rc = get_page_and_type_from_mfn(_mfn(mfn), PGT_l1_page_table, d, flags);
-    if ( unlikely(rc == -EINVAL) && get_l2_linear_pagetable(l2e, pfn, d) )
+    if ( unlikely(rc == -EINVAL) && get_l2_linear_pagetable(l2e, l2mfn, d) )
         rc = 0;
 
     return rc;
@@ -1165,7 +1165,7 @@ get_page_from_l2e(
 define_get_linear_pagetable(l3);
 static int
 get_page_from_l3e(
-    l3_pgentry_t l3e, unsigned long pfn, struct domain *d, unsigned int flags)
+    l3_pgentry_t l3e, unsigned long l3mfn, struct domain *d, unsigned int flags)
 {
     int rc;
 
@@ -1180,7 +1180,7 @@ get_page_from_l3e(
         l3e_get_mfn(l3e), PGT_l2_page_table, d, flags | PTF_preemptible);
     if ( unlikely(rc == -EINVAL) &&
          !is_pv_32bit_domain(d) &&
-         get_l3_linear_pagetable(l3e, pfn, d) )
+         get_l3_linear_pagetable(l3e, l3mfn, d) )
         rc = 0;
 
     return rc;
@@ -1189,7 +1189,7 @@ get_page_from_l3e(
 define_get_linear_pagetable(l4);
 static int
 get_page_from_l4e(
-    l4_pgentry_t l4e, unsigned long pfn, struct domain *d, unsigned int flags)
+    l4_pgentry_t l4e, unsigned long l4mfn, struct domain *d, unsigned int flags)
 {
     int rc;
 
@@ -1202,7 +1202,7 @@ get_page_from_l4e(
 
     rc = get_page_and_type_from_mfn(
         l4e_get_mfn(l4e), PGT_l3_page_table, d, flags | PTF_preemptible);
-    if ( unlikely(rc == -EINVAL) && get_l4_linear_pagetable(l4e, pfn, d) )
+    if ( unlikely(rc == -EINVAL) && get_l4_linear_pagetable(l4e, l4mfn, d) )
         rc = 0;
 
     return rc;
@@ -1329,10 +1329,10 @@ static int put_data_pages(struct page_info *page, bool writeable, int pt_shift)
  * NB. Virtual address 'l2e' maps to a machine address within frame 'pfn'.
  * Note also that this automatically deals correctly with linear p.t.'s.
  */
-static int put_page_from_l2e(l2_pgentry_t l2e, unsigned long pfn,
+static int put_page_from_l2e(l2_pgentry_t l2e, unsigned long l2mfn,
                              unsigned int flags)
 {
-    if ( !(l2e_get_flags(l2e) & _PAGE_PRESENT) || (l2e_get_pfn(l2e) == pfn) )
+    if ( !(l2e_get_flags(l2e) & _PAGE_PRESENT) || (l2e_get_pfn(l2e) == l2mfn) )
         return 1;
 
     if ( l2e_get_flags(l2e) & _PAGE_PSE )
@@ -1340,13 +1340,13 @@ static int put_page_from_l2e(l2_pgentry_t l2e, unsigned long pfn,
                               l2e_get_flags(l2e) & _PAGE_RW,
                               L2_PAGETABLE_SHIFT);
 
-    return put_pt_page(l2e_get_page(l2e), mfn_to_page(_mfn(pfn)), flags);
+    return put_pt_page(l2e_get_page(l2e), mfn_to_page(_mfn(l2mfn)), flags);
 }
 
-static int put_page_from_l3e(l3_pgentry_t l3e, unsigned long pfn,
+static int put_page_from_l3e(l3_pgentry_t l3e, unsigned long l3mfn,
                              unsigned int flags)
 {
-    if ( !(l3e_get_flags(l3e) & _PAGE_PRESENT) || (l3e_get_pfn(l3e) == pfn) )
+    if ( !(l3e_get_flags(l3e) & _PAGE_PRESENT) || (l3e_get_pfn(l3e) == l3mfn) )
         return 1;
 
     if ( unlikely(l3e_get_flags(l3e) & _PAGE_PSE) )
@@ -1354,16 +1354,16 @@ static int put_page_from_l3e(l3_pgentry_t l3e, unsigned long pfn,
                               l3e_get_flags(l3e) & _PAGE_RW,
                               L3_PAGETABLE_SHIFT);
 
-    return put_pt_page(l3e_get_page(l3e), mfn_to_page(_mfn(pfn)), flags);
+    return put_pt_page(l3e_get_page(l3e), mfn_to_page(_mfn(l3mfn)), flags);
 }
 
-static int put_page_from_l4e(l4_pgentry_t l4e, unsigned long pfn,
+static int put_page_from_l4e(l4_pgentry_t l4e, unsigned long l4mfn,
                              unsigned int flags)
 {
-    if ( !(l4e_get_flags(l4e) & _PAGE_PRESENT) || (l4e_get_pfn(l4e) == pfn) )
+    if ( !(l4e_get_flags(l4e) & _PAGE_PRESENT) || (l4e_get_pfn(l4e) == l4mfn) )
         return 1;
 
-    return put_pt_page(l4e_get_page(l4e), mfn_to_page(_mfn(pfn)), flags);
+    return put_pt_page(l4e_get_page(l4e), mfn_to_page(_mfn(l4mfn)), flags);
 }
 
 static int alloc_l1_table(struct page_info *page)
@@ -1460,13 +1460,13 @@ static int create_pae_xen_mappings(struct domain *d, l3_pgentry_t *pl3e)
 static int alloc_l2_table(struct page_info *page, unsigned long type)
 {
     struct domain *d = page_get_owner(page);
-    unsigned long  pfn = mfn_x(page_to_mfn(page));
+    unsigned long  l2mfn = mfn_x(page_to_mfn(page));
     l2_pgentry_t  *pl2e;
     unsigned int   i;
     int            rc = 0;
     unsigned int   partial_flags = page->partial_flags;
 
-    pl2e = map_domain_page(_mfn(pfn));
+    pl2e = map_domain_page(_mfn(l2mfn));
 
     /*
      * NB that alloc_l2_table will never set partial_pte on an l2; but
@@ -1492,7 +1492,7 @@ static int alloc_l2_table(struct page_info *page, unsigned long type)
             rc = -EINTR;
         }
         else
-            rc = get_page_from_l2e(l2e, pfn, d, partial_flags);
+            rc = get_page_from_l2e(l2e, l2mfn, d, partial_flags);
 
         /*
          * It shouldn't be possible for get_page_from_l2e to return
@@ -1559,14 +1559,14 @@ static int alloc_l2_table(struct page_info *page, unsigned long type)
 static int alloc_l3_table(struct page_info *page)
 {
     struct domain *d = page_get_owner(page);
-    unsigned long  pfn = mfn_x(page_to_mfn(page));
+    unsigned long  l3mfn = mfn_x(page_to_mfn(page));
     l3_pgentry_t  *pl3e;
     unsigned int   i;
     int            rc = 0;
     unsigned int   partial_flags = page->partial_flags;
     l3_pgentry_t   l3e = l3e_empty();
 
-    pl3e = map_domain_page(_mfn(pfn));
+    pl3e = map_domain_page(_mfn(l3mfn));
 
     /*
      * PAE guests allocate full pages, but aren't required to initialize
@@ -1603,7 +1603,7 @@ static int alloc_l3_table(struct page_info *page)
             rc = -EINTR;
         }
         else
-            rc = get_page_from_l3e(l3e, pfn, d,
+            rc = get_page_from_l3e(l3e, l3mfn, d,
                                    partial_flags | PTF_retain_ref_on_restart);
 
         if ( rc == -ERESTART )
@@ -1786,8 +1786,8 @@ void zap_ro_mpt(mfn_t mfn)
 static int alloc_l4_table(struct page_info *page)
 {
     struct domain *d = page_get_owner(page);
-    unsigned long  pfn = mfn_x(page_to_mfn(page));
-    l4_pgentry_t  *pl4e = map_domain_page(_mfn(pfn));
+    unsigned long  l4mfn = mfn_x(page_to_mfn(page));
+    l4_pgentry_t  *pl4e = map_domain_page(_mfn(l4mfn));
     unsigned int   i;
     int            rc = 0;
     unsigned int   partial_flags = page->partial_flags;
@@ -1809,7 +1809,7 @@ static int alloc_l4_table(struct page_info *page)
             rc = -EINTR;
         }
         else
-            rc = get_page_from_l4e(l4e, pfn, d,
+            rc = get_page_from_l4e(l4e, l4mfn, d,
                                    partial_flags | PTF_retain_ref_on_restart);
 
         if ( rc == -ERESTART )
@@ -1869,7 +1869,7 @@ static int alloc_l4_table(struct page_info *page)
 
     if ( !rc )
     {
-        init_xen_l4_slots(pl4e, _mfn(pfn),
+        init_xen_l4_slots(pl4e, _mfn(l4mfn),
                           d, INVALID_MFN, VM_ASSIST(d, m2p_strict));
         atomic_inc(&d->arch.pv.nr_l4_pages);
     }
@@ -1896,18 +1896,18 @@ static void free_l1_table(struct page_info *page)
 static int free_l2_table(struct page_info *page)
 {
     struct domain *d = page_get_owner(page);
-    unsigned long pfn = mfn_x(page_to_mfn(page));
+    unsigned long l2mfn = mfn_x(page_to_mfn(page));
     l2_pgentry_t *pl2e;
     int rc = 0;
     unsigned int partial_flags = page->partial_flags,
         i = page->nr_validated_ptes - !(partial_flags & PTF_partial_set);
 
-    pl2e = map_domain_page(_mfn(pfn));
+    pl2e = map_domain_page(_mfn(l2mfn));
 
     for ( ; ; )
     {
         if ( is_guest_l2_slot(d, page->u.inuse.type_info, i) )
-            rc = put_page_from_l2e(pl2e[i], pfn, partial_flags);
+            rc = put_page_from_l2e(pl2e[i], l2mfn, partial_flags);
         if ( rc < 0 )
             break;
 
@@ -1948,17 +1948,17 @@ static int free_l2_table(struct page_info *page)
 static int free_l3_table(struct page_info *page)
 {
     struct domain *d = page_get_owner(page);
-    unsigned long pfn = mfn_x(page_to_mfn(page));
+    unsigned long l3mfn = mfn_x(page_to_mfn(page));
     l3_pgentry_t *pl3e;
     int rc = 0;
     unsigned int partial_flags = page->partial_flags,
         i = page->nr_validated_ptes - !(partial_flags & PTF_partial_set);
 
-    pl3e = map_domain_page(_mfn(pfn));
+    pl3e = map_domain_page(_mfn(l3mfn));
 
     for ( ; ; )
     {
-        rc = put_page_from_l3e(pl3e[i], pfn, partial_flags);
+        rc = put_page_from_l3e(pl3e[i], l3mfn, partial_flags);
         if ( rc < 0 )
             break;
 
@@ -1995,15 +1995,15 @@ static int free_l3_table(struct page_info *page)
 static int free_l4_table(struct page_info *page)
 {
     struct domain *d = page_get_owner(page);
-    unsigned long pfn = mfn_x(page_to_mfn(page));
-    l4_pgentry_t *pl4e = map_domain_page(_mfn(pfn));
+    unsigned long l4mfn = mfn_x(page_to_mfn(page));
+    l4_pgentry_t *pl4e = map_domain_page(_mfn(l4mfn));
     int rc = 0;
     unsigned partial_flags = page->partial_flags,
         i = page->nr_validated_ptes - !(partial_flags & PTF_partial_set);
 
     do {
         if ( is_guest_l4_slot(d, i) )
-            rc = put_page_from_l4e(pl4e[i], pfn, partial_flags);
+            rc = put_page_from_l4e(pl4e[i], l4mfn, partial_flags);
         if ( rc < 0 )
             break;
         partial_flags = 0;