[PATCH 04/04] nested-p2m: add support for 2m pages.

[PATCH 04/04] nested-p2m: add support for 2m pages.

[Christoph Egger]

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-- 
---to satisfy European Law for business letters:
Advanced Micro Devices GmbH
Einsteinring 24, 85689 Dornach b. Muenchen
Geschaeftsfuehrer: Alberto Bozzo, Andrew Bowd
Sitz: Dornach, Gemeinde Aschheim, Landkreis Muenchen
Registergericht Muenchen, HRB Nr. 43632

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2m page support.

Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>

diff -r c0ab99142868 -r b857db54bca3 xen/arch/x86/mm/hap/nested_hap.c
--- a/xen/arch/x86/mm/hap/nested_hap.c
+++ b/xen/arch/x86/mm/hap/nested_hap.c
@@ -96,6 +96,11 @@ nestedp2m_write_p2m_entry(struct p2m_dom
 /********************************************/
 /*          NESTED VIRT FUNCTIONS           */
 /********************************************/
+/* Mask of the GFNs covered by an L2 or L3 superpage */
+/* XXX: defines should be moved to a proper header */
+#define GUEST_L2_GFN_MASK (512 - 1)
+#define GUEST_L3_GFN_MASK ((512 * 512) - 1)
+
 static void
 nestedhap_fix_p2m(struct vcpu *v, struct p2m_domain *p2m, 
                   paddr_t L2_gpa, paddr_t L0_gpa,
@@ -110,10 +115,33 @@ nestedhap_fix_p2m(struct vcpu *v, struct
     /* If this p2m table has been flushed or recycled under our feet, 
      * leave it alone.  We'll pick up the right one as we try to 
      * vmenter the guest. */
-    if ( p2m->cr3 == nhvm_vcpu_hostcr3(v) )
-         rv = set_p2m_entry(p2m, L2_gpa >> PAGE_SHIFT,
-                            page_to_mfn(maddr_to_page(L0_gpa)),
-                            0 /*4K*/, p2mt, p2ma);
+    if ( p2m->cr3 == nhvm_vcpu_hostcr3(v) ) {
+         unsigned long l2gfn;
+         mfn_t l0mfn;
+         struct page_info *l0pg;
+
+         l2gfn = L2_gpa >> PAGE_SHIFT;
+         l0pg = maddr_to_page(L0_gpa);
+         l0mfn = page_to_mfn(l0pg);
+
+         /* Workaround: Map 2m pages instead of 1gb pages till
+          * spage_to_mfn() and page_to_spage() work with
+          * 1gb pages. */
+         if (page_order == PAGE_ORDER_1G)
+             page_order = PAGE_ORDER_2M;
+
+         switch (page_order) {
+         case PAGE_ORDER_4K:
+             break;
+         case PAGE_ORDER_2M:
+             l2gfn &= ~GUEST_L2_GFN_MASK;
+             l0mfn = _mfn(spage_to_mfn(page_to_spage(l0pg)));
+             break;
+         }
+
+         rv = set_p2m_entry(p2m, l2gfn, l0mfn,
+                            page_order, p2mt, p2ma);
+    }
     p2m_unlock(p2m);
 
     if (rv == 0) {
@@ -185,12 +213,13 @@ nestedhvm_hap_nested_page_fault(struct v
     paddr_t L1_gpa, L0_gpa;
     struct domain *d = v->domain;
     struct p2m_domain *p2m, *nested_p2m;
+    unsigned int page_order_21, page_order_10, page_order_20;
 
     p2m = p2m_get_hostp2m(d); /* L0 p2m */
     nested_p2m = p2m_get_nestedp2m(v, nhvm_vcpu_hostcr3(v));
 
     /* walk the L1 P2M table */
-    rv = nestedhap_walk_L1_p2m(v, L2_gpa, &L1_gpa, NULL);
+    rv = nestedhap_walk_L1_p2m(v, L2_gpa, &L1_gpa, &page_order_21);
 
     /* let caller to handle these two cases */
     switch (rv) {
@@ -206,7 +235,7 @@ nestedhvm_hap_nested_page_fault(struct v
     }
 
     /* ==> we have to walk L0 P2M */
-    rv = nestedhap_walk_L0_p2m(p2m, L1_gpa, &L0_gpa, NULL);
+    rv = nestedhap_walk_L0_p2m(p2m, L1_gpa, &L0_gpa, &page_order_10);
 
     /* let upper level caller to handle these two cases */
     switch (rv) {
@@ -221,8 +250,10 @@ nestedhvm_hap_nested_page_fault(struct v
         break;
     }
 
+    page_order_20 = min(page_order_21, page_order_10);
+
     /* fix p2m_get_pagetable(nested_p2m) */
-    nestedhap_fix_p2m(v, nested_p2m, L2_gpa, L0_gpa, PAGE_ORDER_4K,
+    nestedhap_fix_p2m(v, nested_p2m, L2_gpa, L0_gpa, page_order_20,
         p2m_ram_rw,
         p2m_access_rwx /* FIXME: Should use same permission as l1 guest */);
 

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