[Xen-changelog] [xen-unstable] x86: EPT cleanups.

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1233835954 0
# Node ID 5fd1a6951801382c483043579620ae4da9949757
# Parent  416197f0292b62425beb8277e122c41c645d9ab6
x86: EPT cleanups.

Signed-off-by: Xin, Xiaohui <xiaohui.xin@xxxxxxxxx>
---
 xen/arch/x86/mm/hap/p2m-ept.c     |   86 ++++++++++++++++++++++----------------
 xen/include/asm-x86/hvm/vmx/vmx.h |    6 ++
 2 files changed, 56 insertions(+), 36 deletions(-)

diff -r 416197f0292b -r 5fd1a6951801 xen/arch/x86/mm/hap/p2m-ept.c
--- a/xen/arch/x86/mm/hap/p2m-ept.c     Thu Feb 05 12:09:10 2009 +0000
+++ b/xen/arch/x86/mm/hap/p2m-ept.c     Thu Feb 05 12:12:34 2009 +0000
@@ -116,12 +116,12 @@ static int ept_next_level(struct domain 
 }
 
 /*
- * TODO: ept_set_entry() computes 'need_modify_vtd_table' for itself,
+ * ept_set_entry() computes 'need_modify_vtd_table' for itself,
  * by observing whether any gfn->mfn translations are modified.
  */
 static int
-_ept_set_entry(struct domain *d, unsigned long gfn, mfn_t mfn, 
-              unsigned int order, p2m_type_t p2mt, int need_modify_vtd_table)
+ept_set_entry(struct domain *d, unsigned long gfn, mfn_t mfn, 
+              unsigned int order, p2m_type_t p2mt)
 {
     ept_entry_t *table = NULL;
     unsigned long gfn_remainder = gfn, offset = 0;
@@ -131,6 +131,7 @@ _ept_set_entry(struct domain *d, unsigne
     int walk_level = order / EPT_TABLE_ORDER;
     int direct_mmio = (p2mt == p2m_mmio_direct);
     uint8_t igmt = 0;
+    int need_modify_vtd_table = 1;
 
     /* we only support 4k and 2m pages now */
 
@@ -171,14 +172,23 @@ _ept_set_entry(struct domain *d, unsigne
 
             if ( ret == GUEST_TABLE_SUPER_PAGE )
             {
-                ept_entry->mfn = mfn_x(mfn) - offset;
+                if ( ept_entry->mfn == (mfn_x(mfn) - offset) )
+                    need_modify_vtd_table = 0;  
+                else                  
+                    ept_entry->mfn = mfn_x(mfn) - offset;
+
                 if ( ept_entry->avail1 == p2m_ram_logdirty &&
                   p2mt == p2m_ram_rw )
                     for ( i = 0; i < 512; i++ )
                         paging_mark_dirty(d, mfn_x(mfn)-offset+i);
             }
             else
-                ept_entry->mfn = mfn_x(mfn);
+            {
+                if ( ept_entry->mfn == mfn_x(mfn) )
+                    need_modify_vtd_table = 0;
+                else
+                    ept_entry->mfn = mfn_x(mfn);
+            }
 
             ept_entry->avail1 = p2mt;
             ept_entry->rsvd = 0;
@@ -239,7 +249,10 @@ _ept_set_entry(struct domain *d, unsigne
                                                 &igmt, direct_mmio);
         split_ept_entry->igmt = igmt;
 
-        split_ept_entry->mfn = mfn_x(mfn);
+        if ( split_ept_entry->mfn == mfn_x(mfn) )
+            need_modify_vtd_table = 0;
+        else
+            split_ept_entry->mfn = mfn_x(mfn);
         split_ept_entry->avail1 = p2mt;
         ept_p2m_type_to_flags(split_ept_entry, p2mt);
 
@@ -287,17 +300,6 @@ out:
     }
 
     return rv;
-}
-
-static int
-ept_set_entry(struct domain *d, unsigned long gfn, mfn_t mfn,
-              unsigned int order, p2m_type_t p2mt)
-{
-    /* ept_set_entry() are called from set_entry(),
-     * We should always create VT-d page table acording 
-     * to the gfn to mfn translations changes.
-     */
-    return _ept_set_entry(d, gfn, mfn, order, p2mt, 1); 
 }
 
 /* Read ept p2m entries */
@@ -393,6 +395,21 @@ static mfn_t ept_get_entry_current(unsig
     return ept_get_entry(current->domain, gfn, t, q);
 }
 
+/* To test if the new emt type is the same with old,
+ * return 1 to not to reset ept entry.
+ */
+static int need_modify_ept_entry(struct domain *d, unsigned long gfn,
+                                    unsigned long mfn, uint8_t o_igmt,
+                                    uint8_t o_emt, p2m_type_t p2mt)
+{
+    uint8_t igmt, emt;
+    emt = epte_get_entry_emt(d, gfn, mfn, &igmt, 
+                                (p2mt == p2m_mmio_direct));
+    if ( (emt == o_emt) && (igmt == o_igmt) )
+        return 0;
+    return 1; 
+}
+
 void ept_change_entry_emt_with_range(struct domain *d, unsigned long start_gfn,
                  unsigned long end_gfn)
 {
@@ -401,6 +418,7 @@ void ept_change_entry_emt_with_range(str
     uint64_t epte;
     int order = 0;
     unsigned long mfn;
+    uint8_t o_igmt, o_emt;
 
     for ( gfn = start_gfn; gfn <= end_gfn; gfn++ )
     {
@@ -410,7 +428,9 @@ void ept_change_entry_emt_with_range(str
         mfn = (epte & EPTE_MFN_MASK) >> PAGE_SHIFT;
         if ( !mfn_valid(mfn) )
             continue;
-        p2mt = (epte & EPTE_AVAIL1_MASK) >> 8;
+        p2mt = (epte & EPTE_AVAIL1_MASK) >> EPTE_AVAIL1_SHIFT;
+        o_igmt = (epte & EPTE_IGMT_MASK) >> EPTE_IGMT_SHIFT;
+        o_emt = (epte & EPTE_EMT_MASK) >> EPTE_EMT_SHIFT;
         order = 0;
 
         if ( epte & EPTE_SUPER_PAGE_MASK )
@@ -422,30 +442,26 @@ void ept_change_entry_emt_with_range(str
                  * Set emt for super page.
                  */
                 order = EPT_TABLE_ORDER;
-                /* vmx_set_uc_mode() dont' touch the gfn to mfn
-                 * translations, only modify the emt field of the EPT entries.
-                 * so we need not modify the current VT-d page tables.
-                 */
-                _ept_set_entry(d, gfn, _mfn(mfn), order, p2mt, 0);
+                if ( need_modify_ept_entry(d, gfn, mfn, 
+                                            o_igmt, o_emt, p2mt) )
+                    ept_set_entry(d, gfn, _mfn(mfn), order, p2mt);
                 gfn += 0x1FF;
             }
             else
             {
-                /* 1)change emt for partial entries of the 2m area.
-                 * 2)vmx_set_uc_mode() dont' touch the gfn to mfn
-                 * translations, only modify the emt field of the EPT entries.
-                 * so we need not modify the current VT-d page tables.
-                 */
-                _ept_set_entry(d, gfn, _mfn(mfn), order, p2mt,0);
+                /* change emt for partial entries of the 2m area. */
+                if ( need_modify_ept_entry(d, gfn, mfn, 
+                                            o_igmt, o_emt, p2mt) )
+                    ept_set_entry(d, gfn, _mfn(mfn), order, p2mt);
                 gfn = ((gfn >> EPT_TABLE_ORDER) << EPT_TABLE_ORDER) + 0x1FF;
             }
         }
-        else /* 1)gfn assigned with 4k
-              * 2)vmx_set_uc_mode() dont' touch the gfn to mfn
-              * translations, only modify the emt field of the EPT entries.
-              * so we need not modify the current VT-d page tables.
-             */
-            _ept_set_entry(d, gfn, _mfn(mfn), order, p2mt, 0);
+        else /* gfn assigned with 4k */
+        {
+            if ( need_modify_ept_entry(d, gfn, mfn, 
+                                            o_igmt, o_emt, p2mt) )
+                ept_set_entry(d, gfn, _mfn(mfn), order, p2mt);
+        }
     }
 }
 
diff -r 416197f0292b -r 5fd1a6951801 xen/include/asm-x86/hvm/vmx/vmx.h
--- a/xen/include/asm-x86/hvm/vmx/vmx.h Thu Feb 05 12:09:10 2009 +0000
+++ b/xen/include/asm-x86/hvm/vmx/vmx.h Thu Feb 05 12:12:34 2009 +0000
@@ -48,7 +48,11 @@ typedef union {
 #define EPTE_SUPER_PAGE_MASK    0x80
 #define EPTE_MFN_MASK           0x1fffffffffff000
 #define EPTE_AVAIL1_MASK        0xF00
-#define EPTE_EMT_MASK           0x78
+#define EPTE_EMT_MASK           0x38
+#define EPTE_IGMT_MASK          0x40
+#define EPTE_AVAIL1_SHIFT       8
+#define EPTE_EMT_SHIFT          3
+#define EPTE_IGMT_SHIFT         6
 
 void vmx_asm_vmexit_handler(struct cpu_user_regs);
 void vmx_asm_do_vmentry(void);

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-changelog