# HG changeset patch
# User yamahata@xxxxxxxxxxxxx
# Node ID 6e352c348fdb1baedbb35563d4e4e9579749c652
# Parent  68916203eb9717d6fb663fb89eab7378dba9944c
add volatile pte entry of the p2m table.
p2m table are shared by cpu. added volatile as compiler barrier.
PATCHNAME: volatile_pte_t

Signed-off-by: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>

diff -r 68916203eb97 -r 6e352c348fdb xen/arch/ia64/xen/mm.c
--- a/xen/arch/ia64/xen/mm.c	Fri Jun 09 16:22:24 2006 +0900
+++ b/xen/arch/ia64/xen/mm.c	Fri Jun 09 17:50:53 2006 +0900
@@ -349,7 +349,7 @@ unsigned long translate_domain_mpaddr(un
 // pud, pmd, pte page is zero cleared when they are allocated.
 // Their area must be visible before population so that
 // cmpxchg must have release semantics.
-static pte_t*
+static volatile pte_t*
 lookup_alloc_domain_pte(struct domain* d, unsigned long mpaddr)
 {
     struct mm_struct *mm = &d->arch.mm;
@@ -392,11 +392,11 @@ lookup_alloc_domain_pte(struct domain* d
         }
     }
 
-    return pte_offset_map(pmd, mpaddr);
+    return (volatile pte_t*)pte_offset_map(pmd, mpaddr);
 }
 
 //XXX xxx_none() should be used instread of !xxx_present()?
-static pte_t*
+static volatile pte_t*
 lookup_noalloc_domain_pte(struct domain* d, unsigned long mpaddr)
 {
     struct mm_struct *mm = &d->arch.mm;
@@ -417,11 +417,11 @@ lookup_noalloc_domain_pte(struct domain*
     if (unlikely(!pmd_present(*pmd)))
         return NULL;
 
-    return pte_offset_map(pmd, mpaddr);
+    return (volatile pte_t*)pte_offset_map(pmd, mpaddr);
 }
 
 #ifdef CONFIG_XEN_IA64_DOM0_VP
-static pte_t*
+static volatile pte_t*
 lookup_noalloc_domain_pte_none(struct domain* d, unsigned long mpaddr)
 {
     struct mm_struct *mm = &d->arch.mm;
@@ -442,13 +442,13 @@ lookup_noalloc_domain_pte_none(struct do
     if (unlikely(pmd_none(*pmd)))
         return NULL;
 
-    return pte_offset_map(pmd, mpaddr);
+    return (volatile pte_t*)pte_offset_map(pmd, mpaddr);
 }
 
 unsigned long
 ____lookup_domain_mpa(struct domain *d, unsigned long mpaddr)
 {
-    pte_t *pte;
+    volatile pte_t *pte;
 
     pte = lookup_noalloc_domain_pte(d, mpaddr);
     if (pte == NULL)
@@ -515,7 +515,7 @@ __tr_entry_print_all(const char* func, i
 
 unsigned long lookup_domain_mpa(struct domain *d, unsigned long mpaddr)
 {
-    pte_t *pte;
+    volatile pte_t *pte;
 
 #ifdef CONFIG_DOMAIN0_CONTIGUOUS
     if (d == dom0) {
@@ -531,9 +531,10 @@ unsigned long lookup_domain_mpa(struct d
 #endif
     pte = lookup_noalloc_domain_pte(d, mpaddr);
     if (pte != NULL) {
-        if (pte_present(*pte)) {
+        pte_t tmp_pte = *pte;// pte is volatile. copy the value.
+        if (pte_present(tmp_pte)) {
 //printk("lookup_domain_page: found mapping for %lx, pte=%lx\n",mpaddr,pte_val(*pte));
-            return pte_val(*pte);
+            return pte_val(tmp_pte);
         } else if (VMX_DOMAIN(d->vcpu[0]))
             return GPFN_INV_MASK;
     }
@@ -582,7 +583,8 @@ void *domain_mpa_to_imva(struct domain *
 /* Allocate a new page for domain and map it to the specified metaphysical
    address.  */
 struct page_info *
-__assign_new_domain_page(struct domain *d, unsigned long mpaddr, pte_t* pte)
+__assign_new_domain_page(struct domain *d, unsigned long mpaddr,
+                         volatile pte_t* pte)
 {
     struct page_info *p = NULL;
     unsigned long maddr;
@@ -644,7 +646,7 @@ assign_new_domain_page(struct domain *d,
     return __assign_new_domain_page(d, mpaddr, &dummy_pte);
 #else
     struct page_info *p = NULL;
-    pte_t *pte;
+    volatile pte_t *pte;
 
     pte = lookup_alloc_domain_pte(d, mpaddr);
     if (pte_none(*pte)) {
@@ -662,7 +664,7 @@ assign_new_domain0_page(struct domain *d
 assign_new_domain0_page(struct domain *d, unsigned long mpaddr)
 {
 #ifndef CONFIG_DOMAIN0_CONTIGUOUS
-    pte_t *pte;
+    volatile pte_t *pte;
 
     BUG_ON(d != dom0);
     pte = lookup_alloc_domain_pte(d, mpaddr);
@@ -682,7 +684,7 @@ __assign_domain_page(struct domain *d,
                      unsigned long mpaddr, unsigned long physaddr,
                      unsigned long flags)
 {
-    pte_t *pte;
+    volatile pte_t *pte;
     unsigned long arflags = (flags & ASSIGN_readonly)? _PAGE_AR_R: _PAGE_AR_RWX;
 
     pte = lookup_alloc_domain_pte(d, mpaddr);
@@ -811,7 +813,7 @@ assign_domain_page_replace(struct domain
                            unsigned long mfn, unsigned long flags)
 {
     struct mm_struct *mm = &d->arch.mm;
-    pte_t* pte;
+    volatile pte_t* pte;
     pte_t old_pte;
     pte_t npte;
     unsigned long arflags = (flags & ASSIGN_readonly)? _PAGE_AR_R: _PAGE_AR_RWX;
@@ -854,7 +856,7 @@ assign_domain_page_cmpxchg_rel(struct do
                                unsigned long flags)
 {
     struct mm_struct *mm = &d->arch.mm;
-    pte_t* pte;
+    volatile pte_t* pte;
     unsigned long old_mfn;
     unsigned long old_arflags;
     pte_t old_pte;
@@ -866,9 +868,14 @@ assign_domain_page_cmpxchg_rel(struct do
     pte = lookup_alloc_domain_pte(d, mpaddr);
 
  again:
-    old_arflags = pte_val(*pte) & ~_PAGE_PPN_MASK;//XXX
+    old_arflags = pte_val(*pte) & ~_PAGE_PPN_MASK;
     old_mfn = page_to_mfn(old_page);
     old_pte = pfn_pte(old_mfn, __pgprot(old_arflags));
+    if (!pte_present(old_pte)) {
+        DPRINTK("%s: old_pte 0x%lx old_arflags 0x%lx old_mfn 0x%lx\n",
+                __func__, pte_val(old_pte), old_arflags, old_mfn);
+        return -EINVAL;
+    }
 
     new_arflags = (flags & ASSIGN_readonly)? _PAGE_AR_R: _PAGE_AR_RWX;
     new_mfn = page_to_mfn(new_page);
@@ -906,7 +913,7 @@ zap_domain_page_one(struct domain *d, un
 zap_domain_page_one(struct domain *d, unsigned long mpaddr)
 {
     struct mm_struct *mm = &d->arch.mm;
-    pte_t *pte;
+    volatile pte_t *pte;
     pte_t old_pte;
     unsigned long mfn;
     struct page_info *page;
@@ -1026,10 +1033,12 @@ destroy_grant_host_mapping(unsigned long
                unsigned long mfn, unsigned int flags)
 {
     struct domain* d = current->domain;
-    pte_t* pte;
+    volatile pte_t* pte;
+    unsigned long cur_arflags;
+    pte_t cur_pte;
+    pte_t new_pte;
     pte_t old_pte;
-    unsigned long old_mfn = INVALID_MFN;
-    struct page_info* old_page;
+    struct page_info* page;
 
     if (flags & (GNTMAP_application_map | GNTMAP_contains_pte)) {
         DPRINTK("%s: flags 0x%x\n", __func__, flags);
@@ -1037,21 +1046,42 @@ destroy_grant_host_mapping(unsigned long
     }
 
     pte = lookup_noalloc_domain_pte(d, gpaddr);
-    if (pte == NULL || !pte_present(*pte) || pte_pfn(*pte) != mfn)
+    if (pte == NULL) {
+        DPRINTK("%s: gpaddr 0x%lx mfn 0x%lx\n", __func__, gpaddr, mfn);
         return GNTST_general_error;
-
-    // update pte
-    old_pte = ptep_get_and_clear(&d->arch.mm, gpaddr, pte);
-    if (pte_present(old_pte)) {
-        old_mfn = pte_pfn(old_pte);
-    } else {
+    }
+
+ again:
+    cur_arflags = pte_val(*pte) & ~_PAGE_PPN_MASK;
+    cur_pte = pfn_pte(mfn, __pgprot(cur_arflags));
+    if (!pte_present(cur_pte)) {
+        DPRINTK("%s: gpaddr 0x%lx mfn 0x%lx cur_pte\n",
+                __func__, gpaddr, mfn, pte_val(cur_pte));
         return GNTST_general_error;
     }
-    domain_page_flush(d, gpaddr, old_mfn, INVALID_MFN);
-
-    old_page = mfn_to_page(old_mfn);
-    BUG_ON(page_get_owner(old_page) == d);//try_to_clear_PGC_allocate(d, page) is not needed.
-    put_page(old_page);
+    new_pte = __pte(0);
+
+    old_pte = ptep_cmpxchg_rel(&d->arch.mm, gpaddr, pte, cur_pte, new_pte);
+    if (unlikely(!pte_present(old_pte))) {
+        DPRINTK("%s: gpaddr 0x%lx mfn 0x%lx cur_pte 0x%lx old_pte 0x%lx\n",
+                __func__, gpaddr, mfn, pte_val(cur_pte), pte_val(old_pte));
+        return GNTST_general_error;
+    }
+    if (unlikely(pte_val(cur_pte) != pte_val(old_pte))) {
+        if (pte_pfn(old_pte) == mfn) {
+            goto again;
+        }
+        DPRINTK("%s gpaddr 0x%lx mfn 0x%lx cur_pte 0x%lx old_pte 0x%lx\n",
+                __func__, gpaddr, mfn, pte_val(cur_pte), pte_val(old_pte));
+        return GNTST_general_error;
+    }
+    BUG_ON(pte_pfn(old_pte) != mfn);
+
+    domain_page_flush(d, gpaddr, mfn, INVALID_MFN);
+
+    page = mfn_to_page(mfn);
+    BUG_ON(page_get_owner(page) == d);//try_to_clear_PGC_allocate(d, page) is not needed.
+    put_page(page);
 
     return GNTST_okay;
 }
@@ -1196,7 +1226,7 @@ int
 int
 domain_page_mapped(struct domain* d, unsigned long mpaddr)
 {
-    pte_t * pte;
+    volatile pte_t * pte;
 
     pte = lookup_noalloc_domain_pte(d, mpaddr);
     if(pte != NULL && !pte_none(*pte))
diff -r 68916203eb97 -r 6e352c348fdb xen/include/asm-ia64/linux-xen/asm/pgtable.h
--- a/xen/include/asm-ia64/linux-xen/asm/pgtable.h	Fri Jun 09 16:22:24 2006 +0900
+++ b/xen/include/asm-ia64/linux-xen/asm/pgtable.h	Fri Jun 09 17:50:53 2006 +0900
@@ -210,7 +210,7 @@ ia64_phys_addr_valid (unsigned long addr
 #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
 #ifdef XEN
 static inline void
-set_pte_rel(pte_t* ptep, pte_t pteval)
+set_pte_rel(volatile pte_t* ptep, pte_t pteval)
 {
 #if CONFIG_SMP
 	asm volatile ("st8.rel [%0]=%1" ::
@@ -402,8 +402,14 @@ ptep_test_and_clear_dirty (struct vm_are
 }
 #endif
 
+#ifdef XEN
+static inline pte_t
+ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
+		   volatile pte_t *ptep)
+#else
 static inline pte_t
 ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+#endif
 {
 #ifdef CONFIG_SMP
 	return __pte(xchg((long *) ptep, 0));
@@ -416,7 +422,8 @@ ptep_get_and_clear(struct mm_struct *mm,
 
 #ifdef XEN
 static inline pte_t
-ptep_xchg(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t npte)
+ptep_xchg(struct mm_struct *mm, unsigned long addr,
+	  volatile pte_t *ptep, pte_t npte)
 {
 #ifdef CONFIG_SMP
 	return __pte(xchg((long *) ptep, pte_val(npte)));
@@ -428,8 +435,8 @@ ptep_xchg(struct mm_struct *mm, unsigned
 }
 
 static inline pte_t
-ptep_cmpxchg_rel(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
-		 pte_t old_pte, pte_t new_pte)
+ptep_cmpxchg_rel(struct mm_struct *mm, unsigned long addr,
+		 volatile pte_t *ptep, pte_t old_pte, pte_t new_pte)
 {
 #ifdef CONFIG_SMP
 	return __pte(cmpxchg_rel(&pte_val(*ptep),