[PATCH 04/11] x86/MM: Improve p2m type checks.

[Ed White <edmund.h.white@intel.com>]

The alternate p2m code will introduce a new p2m type. In preparation for using
that new type, introduce the type indicator here and fix all the checks
that assume !nestedp2m == hostp2m to explicitly check for hostp2m.

Signed-off-by: Ed White <edmund.h.white@intel.com>
---
 xen/arch/x86/hvm/hvm.c           | 2 +-
 xen/arch/x86/mm/guest_walk.c     | 2 +-
 xen/arch/x86/mm/hap/guest_walk.c | 4 ++--
 xen/arch/x86/mm/p2m-ept.c        | 4 ++--
 xen/arch/x86/mm/p2m.c            | 9 +++++----
 xen/include/asm-x86/p2m.h        | 7 ++++++-
 6 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 3a7367c..b89e9d2 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -2861,7 +2861,7 @@ int hvm_hap_nested_page_fault(paddr_t gpa, unsigned long gla,
     /* Mem sharing: unshare the page and try again */
     if ( npfec.write_access && (p2mt == p2m_ram_shared) )
     {
-        ASSERT(!p2m_is_nestedp2m(p2m));
+        ASSERT(p2m_is_hostp2m(p2m));
         sharing_enomem = 
             (mem_sharing_unshare_page(p2m->domain, gfn, 0) < 0);
         rc = 1;
diff --git a/xen/arch/x86/mm/guest_walk.c b/xen/arch/x86/mm/guest_walk.c
index 1b26175..d8f5a35 100644
--- a/xen/arch/x86/mm/guest_walk.c
+++ b/xen/arch/x86/mm/guest_walk.c
@@ -99,7 +99,7 @@ void *map_domain_gfn(struct p2m_domain *p2m, gfn_t gfn, mfn_t *mfn,
                                  q);
     if ( p2m_is_paging(*p2mt) )
     {
-        ASSERT(!p2m_is_nestedp2m(p2m));
+        ASSERT(p2m_is_hostp2m(p2m));
         if ( page )
             put_page(page);
         p2m_mem_paging_populate(p2m->domain, gfn_x(gfn));
diff --git a/xen/arch/x86/mm/hap/guest_walk.c b/xen/arch/x86/mm/hap/guest_walk.c
index 25d9792..381a196 100644
--- a/xen/arch/x86/mm/hap/guest_walk.c
+++ b/xen/arch/x86/mm/hap/guest_walk.c
@@ -64,7 +64,7 @@ unsigned long hap_p2m_ga_to_gfn(GUEST_PAGING_LEVELS)(
                                      &p2mt, NULL, P2M_ALLOC | P2M_UNSHARE);
     if ( p2m_is_paging(p2mt) )
     {
-        ASSERT(!p2m_is_nestedp2m(p2m));
+        ASSERT(p2m_is_hostp2m(p2m));
         pfec[0] = PFEC_page_paged;
         if ( top_page )
             put_page(top_page);
@@ -106,7 +106,7 @@ unsigned long hap_p2m_ga_to_gfn(GUEST_PAGING_LEVELS)(
             put_page(page);
         if ( p2m_is_paging(p2mt) )
         {
-            ASSERT(!p2m_is_nestedp2m(p2m));
+            ASSERT(p2m_is_hostp2m(p2m));
             pfec[0] = PFEC_page_paged;
             p2m_mem_paging_populate(p2m->domain, gfn_x(gfn));
             return INVALID_GFN;
diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c
index 2b9f07c..255b681 100644
--- a/xen/arch/x86/mm/p2m-ept.c
+++ b/xen/arch/x86/mm/p2m-ept.c
@@ -787,8 +787,8 @@ out:
     if ( needs_sync != sync_off )
         ept_sync_domain(p2m);
 
-    /* For non-nested p2m, may need to change VT-d page table.*/
-    if ( rc == 0 && !p2m_is_nestedp2m(p2m) && need_iommu(d) &&
+    /* For host p2m, may need to change VT-d page table.*/
+    if ( rc == 0 && p2m_is_hostp2m(p2m) && need_iommu(d) &&
          need_modify_vtd_table )
     {
         if ( iommu_hap_pt_share )
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index efa49dd..49b66fb 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -73,6 +73,7 @@ static int p2m_initialise(struct domain *d, struct p2m_domain *p2m)
     p2m->default_access = p2m_access_rwx;
 
     p2m->np2m_base = P2M_BASE_EADDR;
+    p2m->alternate = 0;
 
     if ( hap_enabled(d) && cpu_has_vmx )
         ret = ept_p2m_init(p2m);
@@ -202,7 +203,7 @@ int p2m_init(struct domain *d)
 int p2m_is_logdirty_range(struct p2m_domain *p2m, unsigned long start,
                           unsigned long end)
 {
-    ASSERT(!p2m_is_nestedp2m(p2m));
+    ASSERT(p2m_is_hostp2m(p2m));
     if ( p2m->global_logdirty ||
          rangeset_contains_range(p2m->logdirty_ranges, start, end) )
         return 1;
@@ -263,7 +264,7 @@ mfn_t __get_gfn_type_access(struct p2m_domain *p2m, unsigned long gfn,
 
     if ( (q & P2M_UNSHARE) && p2m_is_shared(*t) )
     {
-        ASSERT(!p2m_is_nestedp2m(p2m));
+        ASSERT(p2m_is_hostp2m(p2m));
         /* Try to unshare. If we fail, communicate ENOMEM without
          * sleeping. */
         if ( mem_sharing_unshare_page(p2m->domain, gfn, 0) < 0 )
@@ -431,7 +432,7 @@ int p2m_alloc_table(struct p2m_domain *p2m)
 
     p2m_lock(p2m);
 
-    if ( !p2m_is_nestedp2m(p2m)
+    if ( p2m_is_hostp2m(p2m)
          && !page_list_empty(&d->page_list) )
     {
         P2M_ERROR("dom %d already has memory allocated\n", d->domain_id);
@@ -1708,7 +1709,7 @@ p2m_flush_table(struct p2m_domain *p2m)
 
     /* "Host" p2m tables can have shared entries &c that need a bit more 
      * care when discarding them */
-    ASSERT(p2m_is_nestedp2m(p2m));
+    ASSERT(!p2m_is_hostp2m(p2m));
     /* Nested p2m's do not do pod, hence the asserts (and no pod lock)*/
     ASSERT(page_list_empty(&p2m->pod.super));
     ASSERT(page_list_empty(&p2m->pod.single));
diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
index 5f7fe71..8193901 100644
--- a/xen/include/asm-x86/p2m.h
+++ b/xen/include/asm-x86/p2m.h
@@ -193,6 +193,9 @@ struct p2m_domain {
      * threaded on in LRU order. */
     struct list_head   np2m_list;
 
+    /* Does this p2m belong to the altp2m code? */
+    bool_t alternate;
+
     /* Host p2m: Log-dirty ranges registered for the domain. */
     struct rangeset   *logdirty_ranges;
 
@@ -290,7 +293,9 @@ struct p2m_domain *p2m_get_nestedp2m(struct vcpu *v, uint64_t np2m_base);
  */
 struct p2m_domain *p2m_get_p2m(struct vcpu *v);
 
-#define p2m_is_nestedp2m(p2m)   ((p2m) != p2m_get_hostp2m((p2m->domain)))
+#define p2m_is_hostp2m(p2m)   ((p2m) == p2m_get_hostp2m((p2m->domain)))
+#define p2m_is_altp2m(p2m)    ((p2m)->alternate)
+#define p2m_is_nestedp2m(p2m) (!p2m_is_altp2m(p2m) && !p2m_ishostp2m(p2m))
 
 #define p2m_get_pagetable(p2m)  ((p2m)->phys_table)
 
-- 
1.9.1