[Xen-devel] [RFC][PATCH] 2/9 Populate-on-demand memory: calls to gfn_to_mfn_query()

["George Dunlap" <dunlapg@xxxxxxxxx>]

Shadow code, and other important places, call gfn_to_mfn_query().  In
particulary, any place that holds the shadow lock must make a query
call.

Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>

diff -r 65c24b33082a xen/arch/x86/hvm/svm/svm.c
--- a/xen/arch/x86/hvm/svm/svm.c        Wed Dec 17 12:59:28 2008 +0000
+++ b/xen/arch/x86/hvm/svm/svm.c        Wed Dec 17 12:59:50 2008 +0000
@@ -888,7 +888,7 @@
      * If this GFN is emulated MMIO or marked as read-only, pass the fault
      * to the mmio handler.
      */
-    mfn = gfn_to_mfn_current(gfn, &p2mt);
+    mfn = gfn_to_mfn_type_current(gfn, &p2mt, p2m_guest);
     if ( (p2mt == p2m_mmio_dm) || (p2mt == p2m_ram_ro) )
     {
         if ( !handle_mmio() )
diff -r 65c24b33082a xen/arch/x86/hvm/vmx/vmx.c
--- a/xen/arch/x86/hvm/vmx/vmx.c        Wed Dec 17 12:59:28 2008 +0000
+++ b/xen/arch/x86/hvm/vmx/vmx.c        Wed Dec 17 12:59:50 2008 +0000
@@ -2099,9 +2099,9 @@
     mfn_t mfn;
     p2m_type_t t;

-    mfn = gfn_to_mfn(d, gfn, &t);
+    mfn = gfn_to_mfn_guest(d, gfn, &t);

-    /* There are two legitimate reasons for taking an EPT violation.
+    /* There are three legitimate reasons for taking an EPT violation.
      * One is a guest access to MMIO space. */
     if ( gla_validity == EPT_GLA_VALIDITY_MATCH && p2m_is_mmio(t) )
     {
@@ -2109,15 +2109,18 @@
         return;
     }

-    /* The other is log-dirty mode, writing to a read-only page */
-    if ( paging_mode_log_dirty(d)
-         && (gla_validity == EPT_GLA_VALIDITY_MATCH
-             || gla_validity == EPT_GLA_VALIDITY_GPT_WALK)
+    /* The second is log-dirty mode, writing to a read-only page;
+     * The third is populating a populate-on-demand page. */
+    if ( (gla_validity == EPT_GLA_VALIDITY_MATCH
+          || gla_validity == EPT_GLA_VALIDITY_GPT_WALK)
          && p2m_is_ram(t) && (t != p2m_ram_ro) )
     {
-        paging_mark_dirty(d, mfn_x(mfn));
-        p2m_change_type(d, gfn, p2m_ram_logdirty, p2m_ram_rw);
-        flush_tlb_mask(d->domain_dirty_cpumask);
+        if ( paging_mode_log_dirty(d) )
+        {
+            paging_mark_dirty(d, mfn_x(mfn));
+            p2m_change_type(d, gfn, p2m_ram_logdirty, p2m_ram_rw);
+            flush_tlb_mask(d->domain_dirty_cpumask);
+        }
         return;
     }

diff -r 65c24b33082a xen/arch/x86/mm/p2m.c
--- a/xen/arch/x86/mm/p2m.c     Wed Dec 17 12:59:28 2008 +0000
+++ b/xen/arch/x86/mm/p2m.c     Wed Dec 17 12:59:50 2008 +0000
@@ -734,7 +734,7 @@
             continue;
         }

-        p2mfn = gfn_to_mfn_foreign(d, gfn, &type);
+        p2mfn = gfn_to_mfn_type_foreign(d, gfn, &type, p2m_query);
         if ( mfn_x(p2mfn) != mfn )
         {
             mpbad++;
@@ -752,7 +752,7 @@

         if ( test_linear && (gfn <= d->arch.p2m->max_mapped_pfn) )
         {
-            lp2mfn = mfn_x(gfn_to_mfn(d, gfn, &type));
+            lp2mfn = mfn_x(gfn_to_mfn_query(d, gfn, &type));
             if ( lp2mfn != mfn_x(p2mfn) )
             {
                 P2M_PRINTK("linear mismatch gfn %#lx -> mfn %#lx "
@@ -963,7 +963,7 @@
     /* First, remove m->p mappings for existing p->m mappings */
     for ( i = 0; i < (1UL << page_order); i++ )
     {
-        omfn = gfn_to_mfn(d, gfn + i, &ot);
+        omfn = gfn_to_mfn_query(d, gfn + i, &ot);
         if ( p2m_is_ram(ot) )
         {
             ASSERT(mfn_valid(omfn));
@@ -988,7 +988,7 @@
              * address */
             P2M_DEBUG("aliased! mfn=%#lx, old gfn=%#lx, new gfn=%#lx\n",
                       mfn + i, ogfn, gfn + i);
-            omfn = gfn_to_mfn(d, ogfn, &ot);
+            omfn = gfn_to_mfn_query(d, ogfn, &ot);
             if ( p2m_is_ram(ot) )
             {
                 ASSERT(mfn_valid(omfn));
@@ -1157,7 +1157,7 @@
     if ( !paging_mode_translate(d) )
         return 0;

-    omfn = gfn_to_mfn(d, gfn, &ot);
+    omfn = gfn_to_mfn_query(d, gfn, &ot);
     if ( p2m_is_ram(ot) )
     {
         ASSERT(mfn_valid(omfn));
diff -r 65c24b33082a xen/arch/x86/mm/shadow/multi.c
--- a/xen/arch/x86/mm/shadow/multi.c    Wed Dec 17 12:59:28 2008 +0000
+++ b/xen/arch/x86/mm/shadow/multi.c    Wed Dec 17 12:59:50 2008 +0000
@@ -2170,7 +2170,7 @@
     if ( guest_l4e_get_flags(new_gl4e) & _PAGE_PRESENT )
     {
         gfn_t gl3gfn = guest_l4e_get_gfn(new_gl4e);
-        mfn_t gl3mfn = gfn_to_mfn(d, gl3gfn, &p2mt);
+        mfn_t gl3mfn = gfn_to_mfn_query(d, gl3gfn, &p2mt);
         if ( p2m_is_ram(p2mt) )
             sl3mfn = get_shadow_status(v, gl3mfn, SH_type_l3_shadow);
         else
@@ -2227,7 +2227,7 @@
     if ( guest_l3e_get_flags(new_gl3e) & _PAGE_PRESENT )
     {
         gfn_t gl2gfn = guest_l3e_get_gfn(new_gl3e);
-        mfn_t gl2mfn = gfn_to_mfn(v->domain, gl2gfn, &p2mt);
+        mfn_t gl2mfn = gfn_to_mfn_query(v->domain, gl2gfn, &p2mt);
         if ( p2m_is_ram(p2mt) )
             sl2mfn = get_shadow_status(v, gl2mfn, SH_type_l2_shadow);
         else
@@ -2276,7 +2276,7 @@
         }
         else
         {
-            mfn_t gl1mfn = gfn_to_mfn(v->domain, gl1gfn, &p2mt);
+            mfn_t gl1mfn = gfn_to_mfn_query(v->domain, gl1gfn, &p2mt);
             if ( p2m_is_ram(p2mt) )
                 sl1mfn = get_shadow_status(v, gl1mfn, SH_type_l1_shadow);
             else
@@ -2346,7 +2346,7 @@
     perfc_incr(shadow_validate_gl1e_calls);

     gfn = guest_l1e_get_gfn(new_gl1e);
-    gmfn = gfn_to_mfn(v->domain, gfn, &p2mt);
+    gmfn = gfn_to_mfn_query(v->domain, gfn, &p2mt);

     l1e_propagate_from_guest(v, new_gl1e, gmfn, &new_sl1e, ft_prefetch, p2mt);
     result |= shadow_set_l1e(v, sl1p, new_sl1e, sl1mfn);
@@ -2406,7 +2406,7 @@
             shadow_l1e_t nsl1e;

             gfn = guest_l1e_get_gfn(gl1e);
-            gmfn = gfn_to_mfn(v->domain, gfn, &p2mt);
+            gmfn = gfn_to_mfn_query(v->domain, gfn, &p2mt);
             l1e_propagate_from_guest(v, gl1e, gmfn, &nsl1e, ft_prefetch, p2mt);
             rc |= shadow_set_l1e(v, sl1p, nsl1e, sl1mfn);

@@ -2723,7 +2723,7 @@

         /* Look at the gfn that the l1e is pointing at */
         gfn = guest_l1e_get_gfn(gl1e);
-        gmfn = gfn_to_mfn(v->domain, gfn, &p2mt);
+        gmfn = gfn_to_mfn_query(v->domain, gfn, &p2mt);

         /* Propagate the entry.  */
         l1e_propagate_from_guest(v, gl1e, gmfn, &sl1e, ft_prefetch, p2mt);
@@ -3079,7 +3079,7 @@

     /* What mfn is the guest trying to access? */
     gfn = guest_l1e_get_gfn(gw.l1e);
-    gmfn = gfn_to_mfn(d, gfn, &p2mt);
+    gmfn = gfn_to_mfn_guest(d, gfn, &p2mt);

     if ( shadow_mode_refcounts(d) &&
          (!p2m_is_valid(p2mt) || (!p2m_is_mmio(p2mt) && !mfn_valid(gmfn))) )
@@ -4126,7 +4126,7 @@
             if ( guest_l3e_get_flags(gl3e[i]) & _PAGE_PRESENT )
             {
                 gl2gfn = guest_l3e_get_gfn(gl3e[i]);
-                gl2mfn = gfn_to_mfn(d, gl2gfn, &p2mt);
+                gl2mfn = gfn_to_mfn_query(d, gl2gfn, &p2mt);
                 if ( p2m_is_ram(p2mt) )
                     flush |= sh_remove_write_access(v, gl2mfn, 2, 0);
             }
@@ -4139,7 +4139,7 @@
             if ( guest_l3e_get_flags(gl3e[i]) & _PAGE_PRESENT )
             {
                 gl2gfn = guest_l3e_get_gfn(gl3e[i]);
-                gl2mfn = gfn_to_mfn(d, gl2gfn, &p2mt);
+                gl2mfn = gfn_to_mfn_query(d, gl2gfn, &p2mt);
                 if ( p2m_is_ram(p2mt) )
                     sh_set_toplevel_shadow(v, i, gl2mfn, (i == 3)
                                            ? SH_type_l2h_shadow
@@ -4525,7 +4525,12 @@
     }

     /* Translate the GFN to an MFN */
-    mfn = gfn_to_mfn(v->domain, _gfn(gfn), &p2mt);
+    /* PoD: query only if shadow lock is held (to avoid deadlock) */
+    if ( shadow_locked_by_me(v->domain) )
+        mfn = gfn_to_mfn_query(v->domain, _gfn(gfn), &p2mt);
+    else
+        mfn = gfn_to_mfn(v->domain, _gfn(gfn), &p2mt);
+
     if ( p2mt == p2m_ram_ro )
         return _mfn(READONLY_GFN);
     if ( !p2m_is_ram(p2mt) )
@@ -4929,7 +4934,7 @@
             {
                 gfn = guest_l1e_get_gfn(*gl1e);
                 mfn = shadow_l1e_get_mfn(*sl1e);
-                gmfn = gfn_to_mfn(v->domain, gfn, &p2mt);
+                gmfn = gfn_to_mfn_query(v->domain, gfn, &p2mt);
                 if ( mfn_x(gmfn) != mfn_x(mfn) )
                     AUDIT_FAIL(1, "bad translation: gfn %" SH_PRI_gfn
                                " --> %" PRI_mfn " != mfn %" PRI_mfn,
@@ -4996,7 +5001,7 @@
             mfn = shadow_l2e_get_mfn(*sl2e);
             gmfn = (guest_l2e_get_flags(*gl2e) & _PAGE_PSE)
                 ? get_fl1_shadow_status(v, gfn)
-                : get_shadow_status(v, gfn_to_mfn(v->domain, gfn, &p2mt),
+                : get_shadow_status(v, gfn_to_mfn_query(v->domain,
gfn, &p2mt),
                                     SH_type_l1_shadow);
             if ( mfn_x(gmfn) != mfn_x(mfn) )
                 AUDIT_FAIL(2, "bad translation: gfn %" SH_PRI_gfn
@@ -5004,7 +5009,7 @@
                            " --> %" PRI_mfn " != mfn %" PRI_mfn,
                            gfn_x(gfn),
                            (guest_l2e_get_flags(*gl2e) & _PAGE_PSE) ? 0
-                           : mfn_x(gfn_to_mfn(v->domain, gfn, &p2mt)),
+                           : mfn_x(gfn_to_mfn_query(v->domain, gfn, &p2mt)),
                            mfn_x(gmfn), mfn_x(mfn));
         }
     });
@@ -5043,7 +5048,7 @@
         {
             gfn = guest_l3e_get_gfn(*gl3e);
             mfn = shadow_l3e_get_mfn(*sl3e);
-            gmfn = get_shadow_status(v, gfn_to_mfn(v->domain, gfn, &p2mt),
+            gmfn = get_shadow_status(v, gfn_to_mfn_query(v->domain,
gfn, &p2mt),
                                      ((GUEST_PAGING_LEVELS == 3 ||
                                        is_pv_32on64_vcpu(v))
                                       && !shadow_mode_external(v->domain)
@@ -5090,7 +5095,7 @@
         {
             gfn = guest_l4e_get_gfn(*gl4e);
             mfn = shadow_l4e_get_mfn(*sl4e);
-            gmfn = get_shadow_status(v, gfn_to_mfn(v->domain, gfn, &p2mt),
+            gmfn = get_shadow_status(v, gfn_to_mfn_query(v->domain,
gfn, &p2mt),
                                      SH_type_l3_shadow);
             if ( mfn_x(gmfn) != mfn_x(mfn) )
                 AUDIT_FAIL(4, "bad translation: gfn %" SH_PRI_gfn
diff -r 65c24b33082a xen/arch/x86/mm/shadow/types.h
--- a/xen/arch/x86/mm/shadow/types.h    Wed Dec 17 12:59:28 2008 +0000
+++ b/xen/arch/x86/mm/shadow/types.h    Wed Dec 17 12:59:50 2008 +0000
@@ -191,6 +191,12 @@
 })
 #endif

+ /* Override gfn_to_mfn to work with gfn_t */
+#undef gfn_to_mfn_query
+#define gfn_to_mfn_query(d, g, t) _gfn_to_mfn_type((d), gfn_x(g),
(t), p2m_query)
+#undef gfn_to_mfn_guest
+#define gfn_to_mfn_guest(d, g, t) _gfn_to_mfn_type((d), gfn_x(g),
(t), p2m_guest)
+
 /* The shadow types needed for the various levels. */

 #if GUEST_PAGING_LEVELS == 2

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