[Xen-changelog] [xen-unstable] [IA64] fix access rights in VHPT when itr.ar!=dtr.ar

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

# HG changeset patch
# User awilliam@xxxxxxxxxxxx
# Date 1174404744 21600
# Node ID c07b1dc6dc6d3b8ee2836090510dcbdf3be4ad74
# Parent  2dbee4f1ee633a69483290fb68e9f482f4ce4214
[IA64] fix access rights in VHPT when itr.ar!=dtr.ar

This is a workaround patch for Windows 2003 Server.
Windows (vcpu>=2) set itr[1].ar=3(RWX) but dtr[1].ar=2(RW).
It causes an impossible INST_ACCESS_RIGHTS interruption via VHPT
which is used for emulating TR.

Surprisingly, windows ordinarily accepts this interruption.
But windows sometimes crashes with the message 'PANIC_STACK_SWITCH'
owing to this interruption.

Signed-off-by: Kouya Shimura <kouya@xxxxxxxxxxxxxx>
---
 xen/arch/ia64/vmx/vmx_process.c |    5 +++++
 xen/arch/ia64/vmx/vtlb.c        |   31 +++++++++++++++++++++++++++++++
 xen/include/asm-ia64/vmmu.h     |    2 ++
 3 files changed, 38 insertions(+)

diff -r 2dbee4f1ee63 -r c07b1dc6dc6d xen/arch/ia64/vmx/vmx_process.c
--- a/xen/arch/ia64/vmx/vmx_process.c   Tue Mar 20 09:24:02 2007 -0600
+++ b/xen/arch/ia64/vmx/vmx_process.c   Tue Mar 20 09:32:24 2007 -0600
@@ -92,6 +92,11 @@ void vmx_reflect_interruption(u64 ifa, u
 
     switch (vec) {
 
+    case 22:   // IA64_INST_ACCESS_RIGHTS_VECTOR
+        if (vhpt_access_rights_fixup(vcpu, ifa, 0))
+            return;
+        break;
+
     case 25:   // IA64_DISABLED_FPREG_VECTOR
 
         if (FP_PSR(vcpu) & IA64_PSR_DFH) {
diff -r 2dbee4f1ee63 -r c07b1dc6dc6d xen/arch/ia64/vmx/vtlb.c
--- a/xen/arch/ia64/vmx/vtlb.c  Tue Mar 20 09:24:02 2007 -0600
+++ b/xen/arch/ia64/vmx/vtlb.c  Tue Mar 20 09:32:24 2007 -0600
@@ -196,6 +196,37 @@ void thash_vhpt_insert(VCPU *v, u64 pte,
         ia64_srlz_i();
     }
 }
+
+int vhpt_access_rights_fixup(VCPU *v, u64 ifa, int is_data)
+{
+    thash_data_t *trp, *data;
+    u64 ps, tag, mask;
+
+    trp = __vtr_lookup(v, ifa, is_data);
+    if (trp) {
+        ps = _REGION_PAGE_SIZE(ia64_get_rr(ifa));
+        if (trp->ps < ps)
+            return 0;
+        ifa = PAGEALIGN(ifa, ps);
+        data = (thash_data_t *)ia64_thash(ifa);
+        tag = ia64_ttag(ifa);
+        do {
+            if (data->etag == tag) {
+                mask = trp->page_flags & PAGE_FLAGS_AR_PL_MASK;
+                if (mask != (data->page_flags & PAGE_FLAGS_AR_PL_MASK)) {
+                    data->page_flags &= ~PAGE_FLAGS_AR_PL_MASK;
+                    data->page_flags |= mask;
+                    machine_tlb_purge(ifa, ps);
+                    return 1;
+                }
+                return 0;
+            }
+            data = data->next;
+        } while(data);
+    }
+    return 0;
+}
+
 /*
  *   vhpt lookup
  */
diff -r 2dbee4f1ee63 -r c07b1dc6dc6d xen/include/asm-ia64/vmmu.h
--- a/xen/include/asm-ia64/vmmu.h       Tue Mar 20 09:24:02 2007 -0600
+++ b/xen/include/asm-ia64/vmmu.h       Tue Mar 20 09:32:24 2007 -0600
@@ -291,6 +291,7 @@ extern int thash_lock_tc(thash_cb_t *hcb
 
 #define   ITIR_RV_MASK      (((1UL<<32)-1)<<32 | 0x3)
 #define   PAGE_FLAGS_RV_MASK    (0x2 | (0x3UL<<50)|(((1UL<<11)-1)<<53))
+#define   PAGE_FLAGS_AR_PL_MASK ((0x7UL<<9)|(0x3UL<<7))
 extern u64 machine_ttag(PTA pta, u64 va);
 extern u64 machine_thash(PTA pta, u64 va);
 extern void purge_machine_tc_by_domid(domid_t domid);
@@ -309,6 +310,7 @@ extern void thash_vhpt_insert(struct vcp
 extern void thash_vhpt_insert(struct vcpu *v, u64 pte, u64 itir, u64 ifa,
                               int type);
 extern u64 guest_vhpt_lookup(u64 iha, u64 *pte);
+extern int vhpt_access_rights_fixup(struct vcpu *v, u64 ifa, int is_data);
 
 static inline void vmx_vcpu_set_tr (thash_data_t *trp, u64 pte, u64 itir, u64 
va, u64 rid)
 {

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