[PATCH v2 10/14] x86/p2m: re-arrange {,__}put_gfn()

[Jan Beulich <jbeulich@xxxxxxxx>]

All explicit callers of __put_gfn() are in HVM-only code and hold a valid
P2M pointer in their hands. Move the paging_mode_translate() check out of
there into put_gfn(), renaming __put_gfn() and making its GFN parameter
type-safe.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxx>
---
v2: Re-base over XSA-388 follow-up.

--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -1955,9 +1955,9 @@ int hvm_hap_nested_page_fault(paddr_t gp
              * altp2m_list lock.
              */
             if ( p2m != hostp2m )
-                __put_gfn(p2m, gfn);
+                p2m_put_gfn(p2m, _gfn(gfn));
             p2m_change_type_one(currd, gfn, p2m_ram_logdirty, p2m_ram_rw);
-            __put_gfn(hostp2m, gfn);
+            p2m_put_gfn(hostp2m, _gfn(gfn));
 
             goto out;
         }
@@ -1979,8 +1979,8 @@ int hvm_hap_nested_page_fault(paddr_t gp
 
  out_put_gfn:
     if ( p2m != hostp2m )
-        __put_gfn(p2m, gfn);
-    __put_gfn(hostp2m, gfn);
+        p2m_put_gfn(p2m, _gfn(gfn));
+    p2m_put_gfn(hostp2m, _gfn(gfn));
  out:
     /*
      * All of these are delayed until we exit, since we might
--- a/xen/arch/x86/include/asm/p2m.h
+++ b/xen/arch/x86/include/asm/p2m.h
@@ -509,9 +509,16 @@ static inline mfn_t __nonnull(3) get_gfn
                                               P2M_ALLOC | P2M_UNSHARE)
 
 /* Will release the p2m_lock for this gfn entry. */
-void __put_gfn(struct p2m_domain *p2m, unsigned long gfn);
+void p2m_put_gfn(struct p2m_domain *p2m, gfn_t gfn);
 
-#define put_gfn(d, gfn) __put_gfn(p2m_get_hostp2m((d)), (gfn))
+static inline void put_gfn(struct domain *d, unsigned long gfn)
+{
+    if ( !paging_mode_translate(d) )
+        /* Nothing to do in this case */
+        return;
+
+    p2m_put_gfn(p2m_get_hostp2m(d), _gfn(gfn));
+}
 
 /* The intent of the "unlocked" accessor is to have the caller not worry about
  * put_gfn. They apply to very specific situations: debug printk's, dumps 
--- a/xen/arch/x86/mm/hap/nested_hap.c
+++ b/xen/arch/x86/mm/hap/nested_hap.c
@@ -149,7 +149,7 @@ static int nestedhap_walk_L0_p2m(
 direct_mmio_out:
     *L0_gpa = (mfn_x(mfn) << PAGE_SHIFT) + (L1_gpa & ~PAGE_MASK);
 out:
-    __put_gfn(p2m, L1_gpa >> PAGE_SHIFT);
+    p2m_put_gfn(p2m, gaddr_to_gfn(L1_gpa));
     return rc;
 }
 
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -333,21 +333,13 @@ mfn_t p2m_get_gfn_type_access(struct p2m
     return mfn;
 }
 
-#endif /* CONFIG_HVM */
-
-void __put_gfn(struct p2m_domain *p2m, unsigned long gfn)
+void p2m_put_gfn(struct p2m_domain *p2m, gfn_t gfn)
 {
-    if ( !p2m || !paging_mode_translate(p2m->domain) )
-        /* Nothing to do in this case */
-        return;
-
-    ASSERT(gfn_locked_by_me(p2m, gfn));
+    ASSERT(gfn_locked_by_me(p2m, gfn_x(gfn)));
 
-    gfn_unlock(p2m, gfn, 0);
+    gfn_unlock(p2m, gfn_x(gfn), 0);
 }
 
-#ifdef CONFIG_HVM
-
 /* Atomically look up a GFN and take a reference count on the backing page. */
 struct page_info *p2m_get_page_from_gfn(
     struct p2m_domain *p2m, gfn_t gfn,
@@ -2201,7 +2193,7 @@ int p2m_altp2m_propagate_change(struct d
             else
             {
                 /* At least 2 altp2m's impacted, so reset everything */
-                __put_gfn(p2m, gfn_x(gfn));
+                p2m_put_gfn(p2m, gfn);
 
                 for ( i = 0; i < MAX_ALTP2M; i++ )
                 {
@@ -2225,7 +2217,7 @@ int p2m_altp2m_propagate_change(struct d
                 ret = rc;
         }
 
-        __put_gfn(p2m, gfn_x(gfn));
+        p2m_put_gfn(p2m, gfn);
     }
 
     altp2m_list_unlock(d);
@@ -2310,7 +2302,7 @@ void audit_p2m(struct domain *d,
              * blow away the m2p entry. */
             set_gpfn_from_mfn(mfn, INVALID_M2P_ENTRY);
         }
-        __put_gfn(p2m, gfn);
+        p2m_put_gfn(p2m, _gfn(gfn));
 
         P2M_PRINTK("OK: mfn=%#lx, gfn=%#lx, p2mfn=%#lx\n",
                        mfn, gfn, mfn_x(p2mfn));