From: awilliam@xenbuild2.aw <awilliam@xenbuild2.aw>
Date: Tue, 20 Mar 2007 15:32:24 +0000 (-0600)
Subject: [IA64] fix access rights in VHPT when itr.ar!=dtr.ar
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~15285
X-Git-Url: https://dgit.raspbian.org/%22http:/www.example.com/cgi/%22https:/%22bookmarks://%22Dat/%22http:/www.example.com/cgi/%22https:/%22bookmarks:/%22Dat?a=commitdiff_plain;h=1264150f8c2f288986f2e79bc45cc89f129b62c8;p=xen.git

[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@jp.fujitsu.com>
---

diff --git a/xen/arch/ia64/vmx/vmx_process.c b/xen/arch/ia64/vmx/vmx_process.c
index 5e40330476..4ee7d4e805 100644
--- a/xen/arch/ia64/vmx/vmx_process.c
+++ b/xen/arch/ia64/vmx/vmx_process.c
@@ -92,6 +92,11 @@ void vmx_reflect_interruption(u64 ifa, u64 isr, u64 iim,
 
     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 --git a/xen/arch/ia64/vmx/vtlb.c b/xen/arch/ia64/vmx/vtlb.c
index 3b6c5377b7..9f01627602 100644
--- a/xen/arch/ia64/vmx/vtlb.c
+++ b/xen/arch/ia64/vmx/vtlb.c
@@ -196,6 +196,37 @@ void thash_vhpt_insert(VCPU *v, u64 pte, u64 itir, u64 va, int type)
         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 --git a/xen/include/asm-ia64/vmmu.h b/xen/include/asm-ia64/vmmu.h
index 905d122f68..84c23c2dfd 100644
--- a/xen/include/asm-ia64/vmmu.h
+++ b/xen/include/asm-ia64/vmmu.h
@@ -291,6 +291,7 @@ extern int thash_lock_tc(thash_cb_t *hcb, u64 va, u64 size, int rid, char cl, in
 
 #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 u64 translate_phy_pte(struct vcpu *v, u64 *pte, u64 itir, u64 va);
 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)
 {