[Xen-devel] [PATCH 2/2] Nested EPT: fixing issue of translate L2 gva to L1 gfn

[Yang Zhang <yang.z.zhang@xxxxxxxxx>]

From: Yang Zhang <yang.z.zhang@xxxxxxxxx>

There is no way to translate L2 gva to L1 gfn directly. To do it,
we need to get L2's gfn first. Then look up the virtual EPT to get L1's gfn.

Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>
---
 xen/arch/x86/mm/p2m.c |   25 ++++++++++++++++++++-----
 1 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index 8f380ed..e92cfbe 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -1605,22 +1605,37 @@ unsigned long paging_gva_to_gfn(struct vcpu *v,
         && paging_mode_hap(v->domain) 
         && nestedhvm_is_n2(v) )
     {
-        unsigned long gfn;
+        unsigned long gfn, l1gfn, exit_qual;
         struct p2m_domain *p2m;
         const struct paging_mode *mode;
-        uint32_t pfec_21 = *pfec;
         uint64_t np2m_base = nhvm_vcpu_p2m_base(v);
+        unsigned int page_order, exit_reason;
+        int rc;
+        uint8_t p2m_acc;
+        struct nestedvmx *nvmx = &vcpu_2_nvmx(v);
 
         /* translate l2 guest va into l2 guest gfn */
         p2m = p2m_get_nestedp2m(v, np2m_base);
         mode = paging_get_nestedmode(v);
         gfn = mode->gva_to_gfn(v, p2m, va, pfec);
 
+        if ( gfn == INVALID_GFN )
+            return gfn;
+
         /* translate l2 guest gfn into l1 guest gfn */
-        return hostmode->p2m_ga_to_gfn(v, hostp2m, np2m_base,
-                                       gfn << PAGE_SHIFT, &pfec_21, NULL);
-    }
+        rc = nept_translate_l2ga(v, gfn << 12 , &page_order, 4, &l1gfn, 
&p2m_acc,
+                                &exit_qual, &exit_reason);
+        if ( rc == EPT_TRANSLATE_VIOLATION || rc == EPT_TRANSLATE_MISCONFIG )
+        {
+            nvmx->ept.exit_reason = exit_reason;
+            nvmx->ept.exit_qual = exit_qual;
+            vcpu_nestedhvm(current).nv_vmexit_pending = 1;
+        }
+        if ( rc == EPT_TRANSLATE_RETRY )
+            *pfec = PFEC_page_paged;
 
+        return l1gfn;
+    }
     return hostmode->gva_to_gfn(v, hostp2m, va, pfec);
 }
 
-- 
1.7.1


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