x86/mm: handle foreign mappings in p2m_entry_modify

So that the specific handling can be removed from
atomic_write_ept_entry and be shared with npt and shadow code.

This commit also removes the check that prevent non-ept PVH dom0 from
mapping foreign pages.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>

diff --git a/xen/arch/x86/mm/hap/hap.c b/xen/arch/x86/mm/hap/hap.c
index fdf77c59a5a427f41b3b8e0aa45800c1d4113e88..412a442b6a3024b8da7a43d313edaf6f1030d903 100644 (file)
--- a/xen/arch/x86/mm/hap/hap.c
+++ b/xen/arch/x86/mm/hap/hap.c
@@ -715,6 +715,7 @@ hap_write_p2m_entry(struct p2m_domain *p2m, unsigned long gfn, l1_pgentry_t *p,
     struct domain *d = p2m->domain;
     uint32_t old_flags;
     bool_t flush_nestedp2m = 0;
+    int rc;
 
     /* We know always use the host p2m here, regardless if the vcpu
      * is in host or guest mode. The vcpu can be in guest mode by
@@ -735,8 +736,14 @@ hap_write_p2m_entry(struct p2m_domain *p2m, unsigned long gfn, l1_pgentry_t *p,
             && perms_strictly_increased(old_flags, l1e_get_flags(new)) );
     }
 
-    p2m_entry_modify(p2m, p2m_flags_to_type(l1e_get_flags(new)),
-                     p2m_flags_to_type(old_flags), level);
+    rc = p2m_entry_modify(p2m, p2m_flags_to_type(l1e_get_flags(new)),
+                          p2m_flags_to_type(old_flags), l1e_get_mfn(new),
+                          l1e_get_mfn(*p), level);
+    if ( rc )
+    {
+        paging_unlock(d);
+        return rc;
+    }
 
     safe_write_pte(p, new);
     if ( old_flags & _PAGE_PRESENT )

diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c
index 0ece6608cba696b4e9c415261506f977bab1a6d6..e3044bee2eb1e24c12510eef159e81218315ac61 100644 (file)
--- a/xen/arch/x86/mm/p2m-ept.c
+++ b/xen/arch/x86/mm/p2m-ept.c
@@ -50,60 +50,15 @@ static int atomic_write_ept_entry(struct p2m_domain *p2m,
                                   ept_entry_t *entryptr, ept_entry_t new,
                                   int level)
 {
-    int rc;
-    unsigned long oldmfn = mfn_x(INVALID_MFN);
-    bool_t check_foreign = (new.mfn != entryptr->mfn ||
-                            new.sa_p2mt != entryptr->sa_p2mt);
-
-    if ( level )
-    {
-        ASSERT(!is_epte_superpage(&new) || !p2m_is_foreign(new.sa_p2mt));
-        write_atomic(&entryptr->epte, new.epte);
-        return 0;
-    }
-
-    if ( unlikely(p2m_is_foreign(new.sa_p2mt)) )
-    {
-        rc = -EINVAL;
-        if ( !is_epte_present(&new) )
-                goto out;
-
-        if ( check_foreign )
-        {
-            struct domain *fdom;
-
-            if ( !mfn_valid(_mfn(new.mfn)) )
-                goto out;
-
-            rc = -ESRCH;
-            fdom = page_get_owner(mfn_to_page(_mfn(new.mfn)));
-            if ( fdom == NULL )
-                goto out;
+    int rc = p2m_entry_modify(p2m, new.sa_p2mt, entryptr->sa_p2mt,
+                              _mfn(new.mfn), _mfn(entryptr->mfn), level);
 
-            /* get refcount on the page */
-            rc = -EBUSY;
-            if ( !get_page(mfn_to_page(_mfn(new.mfn)), fdom) )
-                goto out;
-        }
-    }
-
-    if ( unlikely(p2m_is_foreign(entryptr->sa_p2mt)) && check_foreign )
-        oldmfn = entryptr->mfn;
-
-    p2m_entry_modify(p2m, new.sa_p2mt, entryptr->sa_p2mt, level);
+    if ( rc )
+        return rc;
 
     write_atomic(&entryptr->epte, new.epte);
 
-    if ( unlikely(oldmfn != mfn_x(INVALID_MFN)) )
-        put_page(mfn_to_page(_mfn(oldmfn)));
-
-    rc = 0;
-
- out:
-    if ( rc )
-        gdprintk(XENLOG_ERR, "epte o:%"PRIx64" n:%"PRIx64" rc:%d\n",
-                 entryptr->epte, new.epte, rc);
-    return rc;
+    return 0;
 }
 
 static void ept_p2m_type_to_flags(struct p2m_domain *p2m, ept_entry_t *entry,

diff --git a/xen/arch/x86/mm/p2m-pt.c b/xen/arch/x86/mm/p2m-pt.c
index 4a531fdf9d68ea44c73512fbb745cfee2166179b..e62bafcfb7c28376cef8984646bfbf9faf2d4d6a 100644 (file)
--- a/xen/arch/x86/mm/p2m-pt.c
+++ b/xen/arch/x86/mm/p2m-pt.c
@@ -574,13 +574,6 @@ p2m_pt_set_entry(struct p2m_domain *p2m, gfn_t gfn_, mfn_t mfn,
         __trace_var(TRC_MEM_SET_P2M_ENTRY, 0, sizeof(t), &t);
     }
 
-    if ( unlikely(p2m_is_foreign(p2mt)) )
-    {
-        /* hvm fixme: foreign types are only supported on ept at present */
-        gdprintk(XENLOG_WARNING, "Unimplemented foreign p2m type.\n");
-        return -EINVAL;
-    }
-
     /* Carry out any eventually pending earlier changes first. */
     rc = do_recalc(p2m, gfn);
     if ( rc < 0 )

diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c
index c818112360621f904075f22c6b994f1012ed9c62..025071a1638af1fcb6ed6f60f0f26f0c4d52cbc2 100644 (file)
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -3182,6 +3182,7 @@ shadow_write_p2m_entry(struct p2m_domain *p2m, unsigned long gfn,
                        unsigned int level)
 {
     struct domain *d = p2m->domain;
+    int rc;
 
     paging_lock(d);
 
@@ -3190,8 +3191,14 @@ shadow_write_p2m_entry(struct p2m_domain *p2m, unsigned long gfn,
     if ( likely(d->arch.paging.shadow.total_pages != 0) )
          sh_unshadow_for_p2m_change(d, gfn, p, new, level);
 
-    p2m_entry_modify(p2m, p2m_flags_to_type(l1e_get_flags(new)),
-                     p2m_flags_to_type(l1e_get_flags(*p)), level);
+    rc = p2m_entry_modify(p2m, p2m_flags_to_type(l1e_get_flags(new)),
+                          p2m_flags_to_type(l1e_get_flags(*p)),
+                          l1e_get_mfn(new), l1e_get_mfn(*p), level);
+    if ( rc )
+    {
+        paging_unlock(d);
+        return rc;
+    }
 
     /* Update the entry with new content */
     safe_write_pte(p, new);

diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
index f4ec2becbdc2000c731cc8dacd5c33cd101cceda..2801a8ccca3dbc5dde4e4beac7f6d451dc90af28 100644 (file)
--- a/xen/include/asm-x86/p2m.h
+++ b/xen/include/asm-x86/p2m.h
@@ -932,11 +932,14 @@ int p2m_set_ioreq_server(struct domain *d, unsigned int flags,
 struct hvm_ioreq_server *p2m_get_ioreq_server(struct domain *d,
                                               unsigned int *flags);
 
-static inline void p2m_entry_modify(struct p2m_domain *p2m, p2m_type_t nt,
-                                    p2m_type_t ot, unsigned int level)
+static inline int p2m_entry_modify(struct p2m_domain *p2m, p2m_type_t nt,
+                                   p2m_type_t ot, mfn_t nfn, mfn_t ofn,
+                                   unsigned int level)
 {
-    if ( level != 1 || nt == ot )
-        return;
+    BUG_ON(level > 1 && (nt == p2m_ioreq_server || nt == p2m_map_foreign));
+
+    if ( level != 1 || (nt == ot && mfn_eq(nfn, ofn)) )
+        return 0;
 
     switch ( nt )
     {
@@ -948,6 +951,18 @@ static inline void p2m_entry_modify(struct p2m_domain *p2m, p2m_type_t nt,
         p2m->ioreq.entry_count++;
         break;
 
+    case p2m_map_foreign:
+        if ( !mfn_valid(nfn) )
+        {
+            ASSERT_UNREACHABLE();
+            return -EINVAL;
+        }
+
+        if ( !page_get_owner_and_reference(mfn_to_page(nfn)) )
+            return -EBUSY;
+
+        break;
+
     default:
         break;
     }
@@ -959,9 +974,20 @@ static inline void p2m_entry_modify(struct p2m_domain *p2m, p2m_type_t nt,
         p2m->ioreq.entry_count--;
         break;
 
+    case p2m_map_foreign:
+        if ( !mfn_valid(ofn) )
+        {
+            ASSERT_UNREACHABLE();
+            return -EINVAL;
+        }
+        put_page(mfn_to_page(ofn));
+        break;
+
     default:
         break;
     }
+
+    return 0;
 }
 
 #endif /* _XEN_ASM_X86_P2M_H */