[IA64] fix mis-setting ed bit for itlb entry for hvm domain.

This patch fixes a windows BSOD issue caused by mis-setting pte's ED bit
for itlb entry.
For hash vTLB, it uses unified tlb and doesn't differentiate itc and dtc
in its implementation, so itlb_miss handler may reference dtlb entry in
hash vTLB.
But it may result in issues, because dtlb's ED bit may be different with
itlb's setting.
Since the case is very rare, so just purge the corresponding entry in hash
vTLB and let guest OS to determin how to set ED bit for itlb mapping once
found it.

Signed-off-by : Xiantao Zhang <xiantao.zhang@intel.com>

diff --git a/xen/arch/ia64/vmx/vtlb.c b/xen/arch/ia64/vmx/vtlb.c
index f36580e323d199322c568a35ed66c41b7c596e64..74b0da7f41e09ebc380f7df501de398beaa12bf7 100644 (file)
--- a/xen/arch/ia64/vmx/vtlb.c
+++ b/xen/arch/ia64/vmx/vtlb.c
@@ -678,11 +678,20 @@ thash_data_t *vtlb_lookup(VCPU *v, u64 va,int is_data)
         cch = vtlb_thash(hcb->pta, va, vrr.rrval, &tag);
         do {
             if (cch->etag == tag && cch->ps == ps)
-                return cch;
+                goto found;
             cch = cch->next;
         } while(cch);
     }
     return NULL;
+found:
+    if (unlikely(!cch->ed && is_data == ISIDE_TLB)) {
+        /*The case is very rare, and it may lead to incorrect setting
+          for itlb's ed bit! Purge it from hash vTLB and let guest os
+          determin the ed bit of the itlb entry.*/
+        vtlb_purge(v, va, ps);
+        cch = NULL;
+    }
+    return cch;
 }